Mass extinction

@article{russell1971the11,
    author = "Russell, D. A",
    title = "The disappearance of the dinosaurs",
    year = "1971",
    journal = "Canadian Geographic Journal, v. 83, p. 204-215",
    note = "talkorigins\_source = {true}; raw\_reference = {Russell, D. A., 1971, The disappearance of the dinosaurs: Canadian Geographic Journal, v. 83, p. 204-215.}"
}

@book{bakker1977tetrapod1,
    author = "Bakker, R. T",
    title = "Tetrapod mass extinctions, in Hallem, A., ed., Patterns of Evolution",
    year = "1977",
    publisher = "Amsterdam, Elsevier Scientific Publishing Company, p. 339- 468",
    note = "talkorigins\_source = {true}; raw\_reference = {Bakker, R. T., 1977, Tetrapod mass extinctions, in Hallem, A., ed., Patterns of Evolution: Amsterdam, Elsevier Scientific Publishing Company, p. 339- 468.}"
}

Carbonatites are igneous rocks formed in the crust by fractional crystallization of carbonate-rich parental melts that are mostly mantle derived. They dominantly consist of carbonate minerals such as calcite, dolomite, and ankerite, as well as minor...Read More

@article{doi101146annurevea07050179001115,
    author = "Russell, Dale A.",
    title = "The Enigma of the Extinction of the Dinosaurs",
    year = "1979",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "Carbonatites are igneous rocks formed in the crust by fractional crystallization of carbonate-rich parental melts that are mostly mantle derived. They dominantly consist of carbonate minerals such as calcite, dolomite, and ankerite, as well as minor...Read More",
    url = "https://doi.org/10.1146/annurev.ea.07.050179.001115",
    doi = "10.1146/annurev.ea.07.050179.001115",
    openalex = "W2137926799",
    references = "doi101016s0016787876800077, doi101038242032a0, doi101038264620a0, doi101038scientificamerican066340, doi10108000288306197110426336, doi101126science197429853, doi101126science1994325141, doi101130001676061975861499tmp20co2, doi101139e78109, doi10130683d923ed16c711d78645000102c1865d, openalexw2598847116"
}

Platinum metals are depleted in the earth's crust relative to their cosmic abundance; concentrations of these elements in deep-sea sediments may thus indicate influxes of extraterrestrial material. Deep-sea limestones exposed in Italy, Denmark, and New Zealand show iridium increases of about 30, 160, and 20 times, respectively, above the background level at precisely the time of the Cretaceous-Tertiary extinctions, 65 million years ago. Reasons are given to indicate that this iridium is of extraterrestrial origin, but did not come from a nearby supernova. A hypothesis is suggested which accounts for the extinctions and the iridium observations. Impact of a large earth-crossing asteroid would inject about 60 times the object's mass into the atmosphere as pulverized rock; a fraction of this dust would stay in the stratosphere for several years and be distributed worldwide. The resulting darkness would suppress photosynthesis, and the expected biological consequences match quite closely the extinctions observed in the paleontological record. One prediction of this hypothesis has been verified: the chemical composition of the boundary clay, which is thought to come from the stratospheric dust, is markedly different from that of clay mixed with the Cretaceous and Tertiary limestones, which are chemically similar to each other. Four different independent estimates of the diameter of the asteroid give values that lie in the range 10 ± 4 kilometers.

@article{alvarez1980extraterrestrial,
    author = "Alvarez, Luis W. and Alvarez, Walter and Asaro, Frank and Michel, Helen V.",
    title = "Extraterrestrial Cause for the Cretaceous-Tertiary Extinction",
    year = "1980",
    journal = "Science",
    abstract = "Platinum metals are depleted in the earth's crust relative to their cosmic abundance; concentrations of these elements in deep-sea sediments may thus indicate influxes of extraterrestrial material. Deep-sea limestones exposed in Italy, Denmark, and New Zealand show iridium increases of about 30, 160, and 20 times, respectively, above the background level at precisely the time of the Cretaceous-Tertiary extinctions, 65 million years ago. Reasons are given to indicate that this iridium is of extraterrestrial origin, but did not come from a nearby supernova. A hypothesis is suggested which accounts for the extinctions and the iridium observations. Impact of a large earth-crossing asteroid would inject about 60 times the object's mass into the atmosphere as pulverized rock; a fraction of this dust would stay in the stratosphere for several years and be distributed worldwide. The resulting darkness would suppress photosynthesis, and the expected biological consequences match quite closely the extinctions observed in the paleontological record. One prediction of this hypothesis has been verified: the chemical composition of the boundary clay, which is thought to come from the stratospheric dust, is markedly different from that of clay mixed with the Cretaceous and Tertiary limestones, which are chemically similar to each other. Four different independent estimates of the diameter of the asteroid give values that lie in the range 10 ± 4 kilometers.",
    url = "https://doi.org/10.1126/science.208.4448.1095",
    doi = "10.1126/science.208.4448.1095",
    number = "4448",
    openalex = "W2110619496",
    pages = "1095-1108",
    volume = "208",
    references = "doi101007bf00212446, doi1010160016703773900665, doi1010160031018268900473, doi101038242032a0, doi101038267403a0, doi1010970001069419540800000019, doi101126science18441411079, doi10113000167606197788367ucmsag20co2, doi10113000167606197788374ucmsag20co2, doi10113000167606197788383ucmsag20co2, doi101146annurevea07050179001115, hays1971faunal"
}

@article{doi101038285198a0,
    author = "Smit, Jan and Hertogen, J.",
    title = "An extraterrestrial event at the Cretaceous–Tertiary boundary",
    year = "1980",
    journal = "Nature",
    url = "https://doi.org/10.1038/285198a0",
    doi = "10.1038/285198a0",
    openalex = "W1982572431",
    references = "doi1010160031018268900473, doi10113000167606197788367ucmsag20co2, doi101146annurevea07050179001115"
}

@misc{emiliani1980death3,
    author = "Emiliani, C",
    title = "Death and renovation at the end of the Mesozoic",
    year = "1980",
    howpublished = "Eos, v. 61, no. 1, p. 505-506",
    note = "talkorigins\_source = {true}; raw\_reference = {Emiliani, C., 1980, Death and renovation at the end of the Mesozoic: Eos, v. 61, no. 1, p. 505-506.}"
}

A new compilation of fossil data on invertebrate and vertebrate families indicates that four mass extinctions in the marine realm are statistically distinct from background extinction levels. These four occurred late in the Ordovician, Permian, Triassic, and Cretaceous periods. A fifth extinction event in the Devonian stands out from the background but is not statistically significant in these data. Background extinction rates appear to have declined since Cambrian time, which is consistent with the prediction that optimization of fitness should increase through evolutionary time.

@article{doi101126science21545391501,
    author = "Raup, David M. and Sepkoski, J. John",
    title = "Mass Extinctions in the Marine Fossil Record",
    year = "1982",
    journal = "Science",
    abstract = "A new compilation of fossil data on invertebrate and vertebrate families indicates that four mass extinctions in the marine realm are statistically distinct from background extinction levels. These four occurred late in the Ordovician, Permian, Triassic, and Cretaceous periods. A fifth extinction event in the Devonian stands out from the background but is not statistically significant in these data. Background extinction rates appear to have declined since Cambrian time, which is consistent with the prediction that optimization of fitness should increase through evolutionary time.",
    url = "https://doi.org/10.1126/science.215.4539.1501",
    doi = "10.1126/science.215.4539.1501",
    openalex = "W1976721572",
    references = "doi101017s009483730000511x, doi101017s0094837300006539, doi101130spe89p63, doi105281zenodo16226412, openalexw2335729143, openalexw2591197405, openalexw2596207362"
}

Catastrophic hypotheses for mass extinctions are commonly criticized because many taxa gradually disappear from the fossil record prior to the extinction. Presumably, a geologically instantaneous catastrophe would not cause a reduction in diversity or a series of minor extinctions before the actual mass extinction. Two types of sampling effects, however, could cause taxa to appear to decline before their actual biotic extinction. The first of these is reduced sample size provided in the sedimentary record and the second, which we examine in greater detail, is artificial range truncation. The fossil record is discontinuous in time and the recorded ranges of species or of higher taxa can only extend to their last known occurrence in the fossil record. If the distribution of last occurrences is random with respect to actual biotic extinction, then apparent extinctions will begin well before a mass extinction and will gradually increase in frequency until the mass extinction event, thus giving the appearance of a gradual extinction. Other factors, such as regressions, can exacerbate the bias toward gradual disappearance of taxa from the fossil record. Hence, gradual extinction patterns prior to a mass extinction do not necessarily eliminate catastrophic extinction hypotheses. The recorded ranges of fossils, especially of uncommon taxa or taxa in habitats not represented by a continuous record, may be inadequate to test either gradual or catastrophic hypotheses.

@incollection{doi101130spe190p291,
    author = "Signor, Philip W. and Lipps, Jere H.",
    title = "Sampling bias, gradual extinction patterns and catastrophes in the fossil record",
    year = "1982",
    booktitle = "Geological Society of America eBooks",
    abstract = "Catastrophic hypotheses for mass extinctions are commonly criticized because many taxa gradually disappear from the fossil record prior to the extinction. Presumably, a geologically instantaneous catastrophe would not cause a reduction in diversity or a series of minor extinctions before the actual mass extinction. Two types of sampling effects, however, could cause taxa to appear to decline before their actual biotic extinction. The first of these is reduced sample size provided in the sedimentary record and the second, which we examine in greater detail, is artificial range truncation. The fossil record is discontinuous in time and the recorded ranges of species or of higher taxa can only extend to their last known occurrence in the fossil record. If the distribution of last occurrences is random with respect to actual biotic extinction, then apparent extinctions will begin well before a mass extinction and will gradually increase in frequency until the mass extinction event, thus giving the appearance of a gradual extinction. Other factors, such as regressions, can exacerbate the bias toward gradual disappearance of taxa from the fossil record. Hence, gradual extinction patterns prior to a mass extinction do not necessarily eliminate catastrophic extinction hypotheses. The recorded ranges of fossils, especially of uncommon taxa or taxa in habitats not represented by a continuous record, may be inadequate to test either gradual or catastrophic hypotheses.",
    url = "https://doi.org/10.1130/spe190-p291",
    doi = "10.1130/spe190-p291",
    openalex = "W2414724882"
}

@misc{davis1984extinction2,
    author = "Davis, M. and Hut, P. and Muller, R. A",
    title = "Extinction by periodic comet showers",
    year = "1984",
    howpublished = "Nature, v. 308, p. 715-717",
    note = "talkorigins\_source = {true}; raw\_reference = {Davis, M., Hut, P., and Muller, R. A., 1984, Extinction by periodic comet showers: Nature, v. 308, p. 715-717.}"
}

The temporal distribution of the major extinctions over the past 250 million years has been investigated statistically using various forms of time series analysis. The analyzed record is based on variation in extinction intensity for fossil families of marine vertebrates, invertebrates, and protozoans and contains 12 extinction events. The 12 events show a statistically significant periodicity (P less than 0.01) with a mean interval between events of 26 million years. Two of the events coincide with extinctions that have been previously linked to meteorite impacts (terminal Cretaceous and Late Eocene). Although the causes of the periodicity are unknown, it is possible that they are related to extraterrestrial forces (solar, solar system, or galactic).

@article{doi101073pnas813801,
    author = "Raup, David M. and Sepkoski, J. John",
    title = "Periodicity of extinctions in the geologic past.",
    year = "1984",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The temporal distribution of the major extinctions over the past 250 million years has been investigated statistically using various forms of time series analysis. The analyzed record is based on variation in extinction intensity for fossil families of marine vertebrates, invertebrates, and protozoans and contains 12 extinction events. The 12 events show a statistically significant periodicity (P less than 0.01) with a mean interval between events of 26 million years. Two of the events coincide with extinctions that have been previously linked to meteorite impacts (terminal Cretaceous and Late Eocene). Although the causes of the periodicity are unknown, it is possible that they are related to extraterrestrial forces (solar, solar system, or galactic).",
    url = "https://doi.org/10.1073/pnas.81.3.801",
    doi = "10.1073/pnas.81.3.801",
    openalex = "W2036995861",
    references = "alvarez1980extraterrestrial, doi1010079783642693175, doi1010160016703783901205, doi101016b9780125196406x50017, doi101126science2064415217, doi101126science21545391501, doi101126science2164548885, doi101126science2164548886, doi101126science2214614944, doi102110pec7725"
}

@article{mccartney1984the6,
    author = "McCartney, K",
    title = "The Cretaceous-Tertiary extinctions",
    year = "1984",
    journal = "Journal of Geological Education, v. 32, p. 306-309",
    note = "talkorigins\_source = {true}; raw\_reference = {McCartney, K., 1984, The Cretaceous-Tertiary extinctions: Journal of Geological Education, v. 32, p. 306-309.}"
}

@misc{russell1984the12,
    author = "Russell, D. A",
    title = "The gradual decline of the dinosaurs - fact or fallacy?",
    year = "1984",
    howpublished = "Nature, v. 307, p. 360-361",
    note = "talkorigins\_source = {true}; raw\_reference = {Russell, D. A., 1984, The gradual decline of the dinosaurs - fact or fallacy?: Nature, v. 307, p. 360-361.}"
}

@misc{simon1984mass13,
    author = "Simon, C",
    title = "Mass extinctions and sister stars",
    year = "1984",
    howpublished = "Science News, v. 125, p. 116",
    note = "talkorigins\_source = {true}; raw\_reference = {Simon, C., 1984, Mass extinctions and sister stars: Science News, v. 125, p. 116.}"
}

@misc{stanley1984mass14,
    author = "Stanley, S. M",
    title = "Mass extinctions in the oceans",
    year = "1984",
    howpublished = "Scientific American, v. 250, no. 6, p. 64-72",
    note = "talkorigins\_source = {true}; raw\_reference = {Stanley, S. M., 1984, Mass extinctions in the oceans: Scientific American, v. 250, no. 6, p. 64-72.}"
}

@article{doi1010160012821x86901184,
    author = "Courtillot, Vincent and Besse, Jean and Vandamme, Didier and Montigny, Raymond and Jaeger, Jean‐Jacques and Cappetta, Henri",
    title = "Deccan flood basalts at the Cretaceous/Tertiary boundary?",
    year = "1986",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/0012-821x(86)90118-4",
    doi = "10.1016/0012-821x(86)90118-4",
    openalex = "W1983044404",
    references = "alvarez1980extraterrestrial, doi101007bf01073513, doi1010160012821x77900607, doi1010160040195183900136, doi101029rg018i001p00269, doi101126science22746911161, doi10113000167606197788374ucmsag20co2, doi10113000167606197788383ucmsag20co2, doi101130001676061985961407cg20co2, doi1011300091761319775330rmptsf20co2, doi101306st6398c16"
}

Eight major episodes of biological extinction of marine families over the past 250 million years stand significantly above local background (P < 0.05). These events are more pronounced when analyzed at the level of genus, and generic data exhibit additional apparent extinction events in the Aptian (Cretaceous) and Pliocene (Tertiary) Stages. Time-series analysis of these records strongly suggests a 26-million-year periodicity. This conclusion is robust even when adjusted for simultaneous testing of many trial periods. When the time series is limited to the four best-dated events (Cenomanian, Maestrichtian, upper Eocene, and middle Miocene), the hypothesis of randomness is also rejected for the 26-million-year period (P < 0.0002).

@article{doi101126science11542060,
    author = "Raup, David M. and Sepkoski, J. John",
    title = "Periodic Extinction of Families and Genera",
    year = "1986",
    journal = "Science",
    abstract = "Eight major episodes of biological extinction of marine families over the past 250 million years stand significantly above local background (P < 0.05). These events are more pronounced when analyzed at the level of genus, and generic data exhibit additional apparent extinction events in the Aptian (Cretaceous) and Pliocene (Tertiary) Stages. Time-series analysis of these records strongly suggests a 26-million-year periodicity. This conclusion is robust even when adjusted for simultaneous testing of many trial periods. When the time series is limited to the four best-dated events (Cenomanian, Maestrichtian, upper Eocene, and middle Miocene), the hypothesis of randomness is also rejected for the 26-million-year period (P < 0.0002).",
    url = "https://doi.org/10.1126/science.11542060",
    doi = "10.1126/science.11542060",
    openalex = "W2075334642"
}

The Early Pliocene marine faunas of the southeastern United States were distinct from those of the Bahamas and Caribbean, apparently being separatedfrom them by a zone of cool upwelling. Study of the fates of 361 Early Pliocene bivalve species reveals that a regional mass extinction occurred in the Eastern United States beginning in Late Pliocene time, when continental glaciers expanded, and continued into Early Pleistocene time, eliminating perhaps as many as 65% of the Early Pliocene species. Several patterns suggest that refrigeration during intervals of glacial expansion was the primary cause. The 57 bivalve species that have survivedfrom the tropical zone of Florida all range into nontropical zones today: the mass extinction operated as a thermal filter, eliminating all purely tropical species. Endemic Early Pliocene species experienced especially low survivorship (15%7o) and most of the casualities of these stenothermal forms came early, in Late Pliocene time. A larger percentage of eurythermal Early Pliocene species survived; and most of those that did not, died out relatively late, during cold Early Pleistocene glacial intervals when even Florida became nontropical. Several observations oppose the hypothesis that Pleistocene regressions would have caused heavy extinction even in the absence of refrigeration. Among these are (1) the fact that in the Eastern Pacific Pleistocene extinction was weak even for species endemic to the temperate-warm temperate shelf, which was areally smaller than the shelf of the southeastern United States, and (2) the fact that even Western Atlantic species that were small, abundant, and adapted to muddy conditions suffered heavy losses.

@article{doi1023073514456,
    author = "Stanley, Steven M.",
    title = "Anatomy of a Regional Mass Extinction: Plio-Pleistocene Decimation of the Western Atlantic Bivalve Fauna",
    year = "1986",
    journal = "Palaios",
    abstract = "The Early Pliocene marine faunas of the southeastern United States were distinct from those of the Bahamas and Caribbean, apparently being separatedfrom them by a zone of cool upwelling. Study of the fates of 361 Early Pliocene bivalve species reveals that a regional mass extinction occurred in the Eastern United States beginning in Late Pliocene time, when continental glaciers expanded, and continued into Early Pleistocene time, eliminating perhaps as many as 65\% of the Early Pliocene species. Several patterns suggest that refrigeration during intervals of glacial expansion was the primary cause. The 57 bivalve species that have survivedfrom the tropical zone of Florida all range into nontropical zones today: the mass extinction operated as a thermal filter, eliminating all purely tropical species. Endemic Early Pliocene species experienced especially low survivorship (15\%7o) and most of the casualities of these stenothermal forms came early, in Late Pliocene time. A larger percentage of eurythermal Early Pliocene species survived; and most of those that did not, died out relatively late, during cold Early Pleistocene glacial intervals when even Florida became nontropical. Several observations oppose the hypothesis that Pleistocene regressions would have caused heavy extinction even in the absence of refrigeration. Among these are (1) the fact that in the Eastern Pacific Pleistocene extinction was weak even for species endemic to the temperate-warm temperate shelf, which was areally smaller than the shelf of the southeastern United States, and (2) the fact that even Western Atlantic species that were small, abundant, and adapted to muddy conditions suffered heavy losses.",
    url = "https://doi.org/10.2307/3514456",
    doi = "10.2307/3514456",
    openalex = "W1968964485"
}

@misc{hsu1986the4,
    author = "Hsu, K. J",
    title = "The Great Dying",
    year = "1986",
    howpublished = "New York, Harcourt Brace Jovanovich",
    note = "talkorigins\_source = {true}; raw\_reference = {Hsu, K. J., 1986, The Great Dying: New York, Harcourt Brace Jovanovich.}"
}

@misc{kitchell1986biological5,
    author = "Kitchell, J. A. and Clark, D. L. and Gombos, A. M. and Jr",
    title = "Biological selectivity of extinction",
    year = "1986",
    howpublished = "A link between background and mass extinction: Palaios, v. 1, p. 504-511",
    note = "talkorigins\_source = {true}; raw\_reference = {Kitchell, J. A., Clark, D. L., and Gombos, A. M., Jr., 1986, Biological selectivity of extinction: A link between background and mass extinction: Palaios, v. 1, p. 504-511.}"
}

@misc{raup1986the9,
    author = "Raup, D. M",
    title = "The Nemesis Affair",
    year = "1986",
    howpublished = "New York, W.W. Norton \& Co",
    note = "talkorigins\_source = {true}; raw\_reference = {Raup, D. M., 1986, The Nemesis Affair: New York, W.W. Norton \& Co.}"
}

@misc{retallack1986cretaceoustertiary10,
    author = "Retallack, G. and Leahy, G. D",
    title = "Cretaceous-Tertiary dinosaur extinction",
    year = "1986",
    howpublished = "Science, v. 234, p. 1170-1171",
    note = "talkorigins\_source = {true}; raw\_reference = {Retallack, G., and Leahy, G. D., 1986, Cretaceous-Tertiary dinosaur extinction: Science, v. 234, p. 1170-1171.}"
}

Dinosaur extinction in Montana, Alberta, and Wyoming was a gradual process that began 7 million years before the end of the Cretaceous and accelerated rapidly in the final 0.3 million years of the Cretaceous, during the interval of apparent competition from rapidly evolving immigrating ungulates. This interval involves rapid reduction in both diversity and population density of dinosaurs. The last dinosaurs known are from a channel that contains teeth of Mantuan mammals, seven species of dinosaurs, and Paleocene pollen. The top of this channel is 1.3 meters above the likely position of the iridium anomaly, the Cretaceous/Tertiary boundary.

@article{sloan1986gradual,
    author = "Sloan, Robert E. and Rigby, J. Keith and Van Valen, Leigh M. and Gabriel, Diane",
    title = "Gradual Dinosaur Extinction and Simultaneous Ungulate Radiation in the Hell Creek Formation",
    year = "1986",
    journal = "Science",
    abstract = "Dinosaur extinction in Montana, Alberta, and Wyoming was a gradual process that began 7 million years before the end of the Cretaceous and accelerated rapidly in the final 0.3 million years of the Cretaceous, during the interval of apparent competition from rapidly evolving immigrating ungulates. This interval involves rapid reduction in both diversity and population density of dinosaurs. The last dinosaurs known are from a channel that contains teeth of Mantuan mammals, seven species of dinosaurs, and Paleocene pollen. The top of this channel is 1.3 meters above the likely position of the iridium anomaly, the Cretaceous/Tertiary boundary.",
    url = "https://doi.org/10.1126/science.232.4750.629",
    doi = "10.1126/science.232.4750.629",
    number = "4750",
    pages = "629-633",
    volume = "232"
}

@article{doi101038326143a0,
    author = "Officer, Charles B. and Hallam, Anthony and Drake, Charles L. and Devine, Joseph D.",
    title = "Late Cretaceous and paroxysmal Cretaceous/Tertiary extinctions",
    year = "1987",
    journal = "Nature",
    url = "https://doi.org/10.1038/326143a0",
    doi = "10.1038/326143a0",
    openalex = "W1976899479",
    references = "alvarez1980extraterrestrial, archibald1982upper, doi1010160012821x86901184, doi1010160031018284900944, doi101017s0094837300008071, doi101029jb089ib07p06309, doi101126science1483667220, doi101126science20844481095, doi101126science22346411135, doi101126science2244651867, doi101126science22746911161, doi101126science2314739714, doi101126science2314741979, doi10113000167606197788367ucmsag20co2, doi101130001676061978891389rbeass20co2, doi10113000917613198210153ucbamh20co2, doi101139v74233, doi101146annurevea07050179001115, doi101146annurevea12050184001225, doi1023074156, montanari1986spherules, openalexw2993787886, sloan1986gradual"
}

@misc{officer1987late7,
    author = "Officer, C. B. et al",
    title = "Late Cretaceous and paroxysmal Cretaceous/Tertiary extinctions",
    year = "1987",
    howpublished = "Nature, v. 326, p. 143-149",
    note = "talkorigins\_source = {true}; raw\_reference = {Officer, C. B. et al., 1987, Late Cretaceous and paroxysmal Cretaceous/Tertiary extinctions: Nature, v. 326, p. 143-149.}"
}

@article{doi101038333841a0,
    author = "Duncan, Robert A. and Pyle, Doug",
    title = "Rapid eruption of the Deccan flood basalts at the Cretaceous/Tertiary boundary",
    year = "1988",
    journal = "Nature",
    url = "https://doi.org/10.1038/333841a0",
    doi = "10.1038/333841a0",
    openalex = "W2064814608"
}

@article{doi101038333843a0,
    author = "Courtillot, Vincent and Féraud, Gilbert and Maluski, Henri and Vandamme, Didier and Moreau, M.G. and Besse, Jean",
    title = "Deccan flood basalts and the Cretaceous/Tertiary boundary",
    year = "1988",
    journal = "Nature",
    url = "https://doi.org/10.1038/333843a0",
    doi = "10.1038/333843a0",
    openalex = "W2069910495",
    references = "doi10108002724634198810011673"
}

@article{doi101038337061a0,
    author = "Zachos, James C. and Arthur, Michael A. and Dean, Walter E.",
    title = "Geochemical evidence for suppression of pelagic marine productivity at the Cretaceous/Tertiary boundary",
    year = "1989",
    journal = "Nature",
    url = "https://doi.org/10.1038/337061a0",
    doi = "10.1038/337061a0",
    openalex = "W2025213589"
}

@article{doi1011300091761319890170316pvotao23co2,
    author = "Jaeger, Jean‐Jacques and Courtillot, Vincent and Tapponnier, Paul",
    title = "Paleontological view of the ages of the Deccan Traps, the Cretaceous/Tertiary boundary, and the India-Asia collision",
    year = "1989",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1989)017<0316:pvotao>2.3.co;2",
    doi = "10.1130/0091-7613(1989)017<0316:pvotao>2.3.co;2",
    openalex = "W2055573104"
}

Relic tektites are associated with a Pt‐group metal abundance anomaly and shocked minerals in a thin marl bed that marks the K‐T boundary on Haiti. The presence of these three impact‐produced materials at the precise K‐T boundary enormously strengthens the Alvarez impact extinction hypothesis. The tektites occur in smectite spherules that have external shapes typical of tektites. Their chemical and physical properties are broadly similar to those of other tektite groups, except that the Haitian tektites have lower Si and higher Fe, Ca, and Na. On average, they contain more Sc, V, Cu, Zn, Ga, Sr, Sn, and Ba and less Cr, Ni, Co, B, Mn, and Hf than Other tektite groups. Amounts of rare earth elements (REE) in the tektites indicate that their progenitor materials were not melted mafic or ultramafic oceanic crust; rather they were sedimentary deposits having a bulk composition of andesite. Rare tektites contain unusually high amounts of CaO (∼20%) and S (0.4%), and these data suggest that some target materials consisted of CaSO 4. Anhydrite beds occur in the subsurface at two candidate impact sites (Chicxulub and Manson). Sm‐Nd isotopic data for the tektites indicate that the melted precursor sediments were most likely deposited less than −400 m.y. between the Late Cretaceous and Silurian periods. Major chemical changes accompanied the diagenetic change of glass to smectite. The Haitian tektites are the first datable impact products in K‐T boundary rocks, and 40 Ar‐ 39 Ar ages of the glass show that the K‐T boundary and impact event are coeval at 64.5±0.1 Ma.

@article{doi10102991je02249,
    author = "Izett, G. A.",
    title = "Tektites in Cretaceous‐Tertiary boundary rocks on Haiti and their bearing on the Alvarez Impact Extinction Hypothesis",
    year = "1991",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Relic tektites are associated with a Pt‐group metal abundance anomaly and shocked minerals in a thin marl bed that marks the K‐T boundary on Haiti. The presence of these three impact‐produced materials at the precise K‐T boundary enormously strengthens the Alvarez impact extinction hypothesis. The tektites occur in smectite spherules that have external shapes typical of tektites. Their chemical and physical properties are broadly similar to those of other tektite groups, except that the Haitian tektites have lower Si and higher Fe, Ca, and Na. On average, they contain more Sc, V, Cu, Zn, Ga, Sr, Sn, and Ba and less Cr, Ni, Co, B, Mn, and Hf than Other tektite groups. Amounts of rare earth elements (REE) in the tektites indicate that their progenitor materials were not melted mafic or ultramafic oceanic crust; rather they were sedimentary deposits having a bulk composition of andesite. Rare tektites contain unusually high amounts of CaO (∼20\%) and S (0.4\%), and these data suggest that some target materials consisted of CaSO 4. Anhydrite beds occur in the subsurface at two candidate impact sites (Chicxulub and Manson). Sm‐Nd isotopic data for the tektites indicate that the melted precursor sediments were most likely deposited less than −400 m.y. between the Late Cretaceous and Silurian periods. Major chemical changes accompanied the diagenetic change of glass to smectite. The Haitian tektites are the first datable impact products in K‐T boundary rocks, and 40 Ar‐ 39 Ar ages of the glass show that the K‐T boundary and impact event are coeval at 64.5±0.1 Ma.",
    url = "https://doi.org/10.1029/91je02249",
    doi = "10.1029/91je02249",
    openalex = "W2128408803"
}

@article{doi101038353839a0,
    author = "Sigurdsson, Haraldur and Bonté, Ph. and Turpin, Laurent and Chaussidon, Marc and Métrich, Nicole and Steinberg, M. and Pradel, P. and D’Hondt, Steven",
    title = "Geochemical constraints on source region of Cretaceous/Tertiary impact glasses",
    year = "1991",
    journal = "Nature",
    url = "https://doi.org/10.1038/353839a0",
    doi = "10.1038/353839a0",
    openalex = "W2051660622"
}

(40)Ar/(39)Ar dating of tektites discovered recently in Cretaceous-Tertiary (K-T) boundary marine sedimentary rocks on Haiti indicates that the K-T boundary and impact event are coeval at 64.5 +/- 0.1 million years ago. Sanidine from a bentonite that lies directly above the K-T boundary in continental, coal-bearing, sedimentary rocks of Montana was also dated and has a (40)Ar/(39)Ar age of 64.6 +/- 0.2 million years ago, which is indistinguishable statistically from the age of the tektites.

@article{doi101126science25250121539,
    author = "Izett, G. A. and Dalrymple, G. Brent and Snee, Lawrence W.",
    title = "40 Ar/ 39 Ar Age of Cretaceous-Tertiary Boundary Tektites from Haiti",
    year = "1991",
    journal = "Science",
    abstract = "(40)Ar/(39)Ar dating of tektites discovered recently in Cretaceous-Tertiary (K-T) boundary marine sedimentary rocks on Haiti indicates that the K-T boundary and impact event are coeval at 64.5 +/- 0.1 million years ago. Sanidine from a bentonite that lies directly above the K-T boundary in continental, coal-bearing, sedimentary rocks of Montana was also dated and has a (40)Ar/(39)Ar age of 64.6 +/- 0.2 million years ago, which is indistinguishable statistically from the age of the tektites.",
    url = "https://doi.org/10.1126/science.252.5012.1539",
    doi = "10.1126/science.252.5012.1539",
    openalex = "W2011903534"
}

The marker bed at the Cretaceous-Tertiary boundary of the Beloc Formation (southern Haiti) contains abundant coarse-grained microtektites and minor amounts of shocked quartz grains in the basal part. The upper part is composed of medium-grained marl with amalgamated microtektite lenses and finer-grained marl lenses disseminated throughout. Field and petrographic observations, and the distribution of planktonic foraminifera suggest that the bed formed from a complex sequence of events. A bolide impact nearby produced microtektites that sett1led to form a nearly pure layer at the base. Vaporized materials with anomalously high extraterrestrial components settled last, along with carbonate sediments. The entire bed became sparsely consolidated. Subsequently, another major disruptive event, perhaps a giant tsunami, partly reworked the initial deposit. Cohesive fragments of the original marker bed mixed with exotic materials were redeposited as lenticular bodies. This process also may have caused further mixing of Cretaceous and Tertiary microfossils, as observed at Beloc and elsewhere.

@article{doi101126science25250131690,
    author = "Maurrasse, F. J. and Sen, Gautam",
    title = "Impacts, Tsunamis, and the Haitian Cretaceous-Tertiary Boundary Layer",
    year = "1991",
    journal = "Science",
    abstract = "The marker bed at the Cretaceous-Tertiary boundary of the Beloc Formation (southern Haiti) contains abundant coarse-grained microtektites and minor amounts of shocked quartz grains in the basal part. The upper part is composed of medium-grained marl with amalgamated microtektite lenses and finer-grained marl lenses disseminated throughout. Field and petrographic observations, and the distribution of planktonic foraminifera suggest that the bed formed from a complex sequence of events. A bolide impact nearby produced microtektites that sett1led to form a nearly pure layer at the base. Vaporized materials with anomalously high extraterrestrial components settled last, along with carbonate sediments. The entire bed became sparsely consolidated. Subsequently, another major disruptive event, perhaps a giant tsunami, partly reworked the initial deposit. Cohesive fragments of the original marker bed mixed with exotic materials were redeposited as lenticular bodies. This process also may have caused further mixing of Cretaceous and Tertiary microfossils, as observed at Beloc and elsewhere.",
    url = "https://doi.org/10.1126/science.252.5013.1690",
    doi = "10.1126/science.252.5013.1690",
    openalex = "W1973143059",
    references = "alvarez1980extraterrestrial, doi101007springerreference4923, doi1010160025322770900010, doi1010160377839888900059, doi101029jb093ib05p04279, doi101029jb094ib12p17465, doi101038343251a0, doi101086625710, doi101126science2414865567, doi101130spe190p305, doi101144pygs3511, openalexw1570283708"
}

@article{doi1011300091761319910190867ccapct23co2,
    author = "Hildebrand, A. R. and Penfield, G. T. and Kring, D. A. and Pilkington, Mark and Z., Antonio Camargo and Jacobsen, S. B. and Boynton, W. V.",
    title = "Chicxulub Crater: A possible Cretaceous/Tertiary boundary impact crater on the Yucatán Peninsula, Mexico",
    year = "1991",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1991)019<0867:ccapct>2.3.co;2",
    doi = "10.1130/0091-7613(1991)019<0867:ccapct>2.3.co;2",
    openalex = "W2126767740"
}

@article{doi101038359819a0,
    author = "Sharpton, V. L. and Dalrymple, G. Brent and Marín, Luis E. and Ryder, G. and Schuraytz, B. C. and Urrutia‐Fucugauchi, J.",
    title = "New links between the Chicxulub impact structure and the Cretaceous/Tertiary boundary",
    year = "1992",
    journal = "Nature",
    url = "https://doi.org/10.1038/359819a0",
    doi = "10.1038/359819a0",
    openalex = "W2014344490",
    references = "doi101007bf00268927, doi1010160031920184900736, doi10102991je02249, doi101038353839a0, doi101038358141a0, doi101126science25250121539, doi101126science2575072954, doi1011300091761319775330rmptsf20co2, doi1011300091761319910190867ccapct23co2, doi1011300091761319920200099tbdwcu23co2"
}

(40)Ar/(39)Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded well-behaved incremental heating spectra with a mean plateau age of 64.98 +/- 0.05 million years ago (Ma). The glassy melt rock of andesitic composition was obtained from core 9 (1390 to 1393 meters) in the Chicxulub 1 well. The age of the melt rock is virtually indistinguishable from (40)Ar/(39)Ar ages obtained on tektite glass from Beloc, Haiti, and Arroyo el Mimbral, northeastern Mexico, of 65.01 +/- 0.08 Ma (mean plateau age for Beloc) and 65.07 +/- 0.10 Ma (mean total fusion age for both sites). The (40)Ar/(39)Ar ages, in conjunction with geochemical and petrological similarities, strengthen the recent suggestion that the Chicxulub structure is the source for the Haitian and Mexican tektites and is a viable candidate for the Cretaceous-Tertiary boundary impact site.

@article{doi101126science2575072954,
    author = "Swisher, Carl C. and Grajales-Nishimura, José Manuel and Montanari, Alessandro and Margolis, Stanley V. and Claeys, Philippe and Álvarez, Walter and Renne, Paul R. and Cedillo-Pardoa, Esteban and Maurrasse, F. J. and Curtis, Garniss H. and Smit, Jan and McWilliams, Michael",
    title = "Coeval 40 Ar/ 39 Ar Ages of 65.0 Million Years Ago from Chicxulub Crater Melt Rock and Cretaceous-Tertiary Boundary Tektites",
    year = "1992",
    journal = "Science",
    abstract = "(40)Ar/(39)Ar dating of drill core samples of a glassy melt rock recovered from beneath a massive impact breccia contained within the 180-kilometer subsurface Chicxulub crater in Yucatán, Mexico, has yielded well-behaved incremental heating spectra with a mean plateau age of 64.98 +/- 0.05 million years ago (Ma). The glassy melt rock of andesitic composition was obtained from core 9 (1390 to 1393 meters) in the Chicxulub 1 well. The age of the melt rock is virtually indistinguishable from (40)Ar/(39)Ar ages obtained on tektite glass from Beloc, Haiti, and Arroyo el Mimbral, northeastern Mexico, of 65.01 +/- 0.08 Ma (mean plateau age for Beloc) and 65.07 +/- 0.10 Ma (mean total fusion age for both sites). The (40)Ar/(39)Ar ages, in conjunction with geochemical and petrological similarities, strengthen the recent suggestion that the Chicxulub structure is the source for the Haitian and Mexican tektites and is a viable candidate for the Cretaceous-Tertiary boundary impact site.",
    url = "https://doi.org/10.1126/science.257.5072.954",
    doi = "10.1126/science.257.5072.954",
    openalex = "W2087549641",
    references = "doi1010160012821x77900607, doi1010160016703777901843, doi101016016896228790025x, doi101126science25250131690, doi101126science2535016176, doi1011300091761319910190867ccapct23co2, doi1011300091761319920200099tbdwcu23co2, doi1015159781400862924, doi10151597814008629241, doi102475ajs2622145, openalexw1586251589"
}

The Paraná-Etendeka flood volcanic event produced approximately 1.5 x 10(6) cubic kilometers of volcanic rocks, ranging from basalts to rhyolites, before the separation of South America and Africa during the Cretaceous period. New (40)Ar/(39)Ar data combined with earlier paleomagnetic results indicate that Paraná flood volcanism in southern Brazil began at 133 +/- 1 million years ago and lasted less than 1 million years. The implied mean eruption rate on the order of 1.5 cubic kilometers per year is consistent with a mantle plume origin for the event and is comparable to eruption rates determined for other well-documented continental flood volcanic events. Paraná flood volcanism occurred before the initiation of sea floor spreading in the South Atlantic and was probably precipitated by uplift and weakening of the lithosphere by the Tristan da Cunha plume. The Parana event postdates most current estimates for the age of the faunal mass extinction associated with the Jurassic-Cretaceous boundary.

@article{doi101126science2585084975,
    author = "Renne, Paul R. and Ernesto, Márcia and Pacca, I. G. and Coe, Robert S. and Glen, Jonathon M. and Prévôt, Michel and Perrin, Mireille",
    title = "The Age of Paraná Flood Volcanism, Rifting of Gondwanaland, and the Jurassic-Cretaceous Boundary",
    year = "1992",
    journal = "Science",
    abstract = "The Paraná-Etendeka flood volcanic event produced approximately 1.5 x 10(6) cubic kilometers of volcanic rocks, ranging from basalts to rhyolites, before the separation of South America and Africa during the Cretaceous period. New (40)Ar/(39)Ar data combined with earlier paleomagnetic results indicate that Paraná flood volcanism in southern Brazil began at 133 +/- 1 million years ago and lasted less than 1 million years. The implied mean eruption rate on the order of 1.5 cubic kilometers per year is consistent with a mantle plume origin for the event and is comparable to eruption rates determined for other well-documented continental flood volcanic events. Paraná flood volcanism occurred before the initiation of sea floor spreading in the South Atlantic and was probably precipitated by uplift and weakening of the lithosphere by the Tristan da Cunha plume. The Parana event postdates most current estimates for the age of the faunal mass extinction associated with the Jurassic-Cretaceous boundary.",
    url = "https://doi.org/10.1126/science.258.5084.975",
    doi = "10.1126/science.258.5084.975",
    openalex = "W2048722474",
    references = "doi101126science2414866663, doi101130001676061985961419acajg20co2"
}

The hypothesis of Cretaceous-Tertiary (K-T) boundary impact on Yucatán, Mexico, predicts that nearby sites should show evidence of proximal impact ejecta and disturbance by giant waves. An outcrop along the Arroyo el Mimbral in northeastern Mexico contains a layered clastic unit up to 3 m thick that interrupts a biostratigraphically complete pelagic-marl sequence deposited at more than 400 m water depth. The marls were found to be unsuitable for determining magnetostratigraphy, but foraminiferal biostratigraphy places the clastic unit precisely at the K-T boundary. We interpret this clastic unit as the deposit of a megawave or tsunami produced by an extraterrestrial impact. The clastic unit comprises three main subunits. (1) The basal "spherule bed" contains glass in the form of tektites and microtektites, glass spherules replaced by chlorite-smectite and calcite, and quartz grains showing probable shock features. This bed is interpreted as a channelized deposit of proximal ejecta. (2) A set of lenticular, massive, graded "laminated beds" contains intraclasts and abundant plant debris, and may be the result of megawave backwash that carried coarse debris from shallow parts of the continental margin into deeper water. (3) At the top, several thin "ripple beds" composed of fine sand are separated by clay drapes; they are interpreted as deposits of oscillating currents, perhaps a seiche. An iridium anomaly (921 +/- 23 pg/g) is observed at the top of the ripple beds. Our observations at the Mimbral locality support the hypothesis of a K-T impact on nearby Yucatán.

@article{doi1011300091761319920200099tbdwcu23co2,
    author = "Smit, Jan and Montanari, Alessandro and Swinburne, Nicola H.M. and Álvarez, Walter and Hildebrand, A. R. and Margolis, Stanley V. and Claeys, Philippe and Lowrie, William and Asaro, Frank",
    title = "Tektite-bearing, deep-water clastic unit at the Cretaceous-Tertiary boundary in northeastern Mexico",
    year = "1992",
    journal = "Geology",
    abstract = {The hypothesis of Cretaceous-Tertiary (K-T) boundary impact on Yucatán, Mexico, predicts that nearby sites should show evidence of proximal impact ejecta and disturbance by giant waves. An outcrop along the Arroyo el Mimbral in northeastern Mexico contains a layered clastic unit up to 3 m thick that interrupts a biostratigraphically complete pelagic-marl sequence deposited at more than 400 m water depth. The marls were found to be unsuitable for determining magnetostratigraphy, but foraminiferal biostratigraphy places the clastic unit precisely at the K-T boundary. We interpret this clastic unit as the deposit of a megawave or tsunami produced by an extraterrestrial impact. The clastic unit comprises three main subunits. (1) The basal "spherule bed" contains glass in the form of tektites and microtektites, glass spherules replaced by chlorite-smectite and calcite, and quartz grains showing probable shock features. This bed is interpreted as a channelized deposit of proximal ejecta. (2) A set of lenticular, massive, graded "laminated beds" contains intraclasts and abundant plant debris, and may be the result of megawave backwash that carried coarse debris from shallow parts of the continental margin into deeper water. (3) At the top, several thin "ripple beds" composed of fine sand are separated by clay drapes; they are interpreted as deposits of oscillating currents, perhaps a seiche. An iridium anomaly (921 +/- 23 pg/g) is observed at the top of the ripple beds. Our observations at the Mimbral locality support the hypothesis of a K-T impact on nearby Yucatán.},
    url = "https://doi.org/10.1130/0091-7613(1992)020<0099:tbdwcu>2.3.co;2",
    doi = "10.1130/0091-7613(1992)020<0099:tbdwcu>2.3.co;2",
    openalex = "W1972546096"
}

@article{doi1010160012821x93900152,
    author = "Venkatesan, T. R. and Pande, Kanchan and Gopalan, K.",
    title = "Did Deccan volcanism pre-date the Cretaceous/Tertiary transition?",
    year = "1993",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/0012-821x(93)90015-2",
    doi = "10.1016/0012-821x(93)90015-2",
    openalex = "W1989891127"
}

@article{doi1011300091761319930210797docdnt23co2,
    author = "Stinnesbeck, Wolfgang and Barbarin, J. M. and Keller, Gerta and Lopez-Oliva, J. G. and Pivnik, David A. and Lyons, J. B. and Officer, C. B. and Adatte, Thierry and Graup, G. and Rocchia, R.",
    title = {Deposition of channel deposits near the Cretaceous-Tertiary boundary in northeastern Mexico: Catastrophic or "normal" sedimentary deposits?},
    year = "1993",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1993)021<0797:docdnt>2.3.co;2",
    doi = "10.1130/0091-7613(1993)021<0797:docdnt>2.3.co;2",
    openalex = "W2315925515"
}

Evolutiona ry trends among mammals over the past 66 Myr have been profou ndly influenced by changing climat es, in tum the result of tectonic events. The global trop ical forest type of ecosystem of the early Tertiary was disrupted by Late Eocene climatic changes, with the extinction of most archaic mammalian lineages and the appearance of most modem famil ies. Later Tertiary trends reflect increasing aridity, with the appearance of open-habitat mammals such as grazing ungulate s, although true grasslands probably did not appear until the Late Miocene in the New World and the Pliocene in the Old World. Patterns of mammalian diversity track paleote mperature curves for the northern latitudes, with maxima in the early Mid dle Eocene and early Middle Miocene. Major dispersals occurred at times of sea level lows, resulting in loss of endemism in originally isolated continents such as South America and Afr ica, and changes in faunal composition across Holarctica. Dispersal in con junction with climatic changes accounted for maj or extinction events in the Late Eocene to Early Oligoce ne, at the end of the Miocene, and in the mid Pliocene. Outstanding problems include the origin and dispersal routes of many extant orders that appeared at the start of the Eocene and the

@article{doi101146annureves24110193002343,
    author = "Janis, Christine M.",
    title = "Tertiary Mammal Evolution in the Context of Changing Climates, Vegetation, and Tectonic Events",
    year = "1993",
    journal = "Annual Review of Ecology and Systematics",
    abstract = "Evolutiona ry trends among mammals over the past 66 Myr have been profou ndly influenced by changing climat es, in tum the result of tectonic events. The global trop ical forest type of ecosystem of the early Tertiary was disrupted by Late Eocene climatic changes, with the extinction of most archaic mammalian lineages and the appearance of most modem famil ies. Later Tertiary trends reflect increasing aridity, with the appearance of open-habitat mammals such as grazing ungulate s, although true grasslands probably did not appear until the Late Miocene in the New World and the Pliocene in the Old World. Patterns of mammalian diversity track paleote mperature curves for the northern latitudes, with maxima in the early Mid dle Eocene and early Middle Miocene. Major dispersals occurred at times of sea level lows, resulting in loss of endemism in originally isolated continents such as South America and Afr ica, and changes in faunal composition across Holarctica. Dispersal in con junction with climatic changes accounted for maj or extinction events in the Late Eocene to Early Oligoce ne, at the end of the Miocene, and in the mid Pliocene. Outstanding problems include the origin and dispersal routes of many extant orders that appeared at the start of the Eocene and the",
    url = "https://doi.org/10.1146/annurev.es.24.110193.002343",
    doi = "10.1146/annurev.es.24.110193.002343",
    openalex = "W2178293737",
    references = "crossref1990the, doi101016004724849090011y, doi101038267399a0, doi101111j1469185x1982tb00370x, doi101130spe243p71, doi1015159781400862924, doi10151597814008629241, doi1023072398811, doi1023072399449, doi1023072992083, openalexw2989964553"
}

@article{doi1010160012821x94901864,
    author = "Pope, Kevin and Baines, K. H. and Ocampo, Adriana and Ivanov, B. A.",
    title = "Impact winter and the Cretaceous/Tertiary extinctions: Results of a Chicxulub asteroid impact model",
    year = "1994",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/0012-821x(94)90186-4",
    doi = "10.1016/0012-821x(94)90186-4",
    openalex = "W2078061116"
}

@article{doi1011300091761319940220877gecptc23co2,
    author = "Barrera, Enriqueta",
    title = "Global environmental changes preceding the Cretaceous-Tertiary boundary: Early-late Maastrichtian transition",
    year = "1994",
    journal = "Geology",
    url = "https://doi.org/10.1130/0091-7613(1994)022<0877:gecptc>2.3.co;2",
    doi = "10.1130/0091-7613(1994)022<0877:gecptc>2.3.co;2",
    openalex = "W2071272856"
}

The transition from the Eocene to the Oligocene Epochs, from about 40 to 30 Ma (million years ago), was the most significant interval in Earth history since the dinosaurs died out 65 Ma. From the warm, equable greenhouse climate of the early Eocene (a relict of the age of dinosaurs), the Earth experienced major climatic changes. Global temperature plum­ meted, and the first Antarctic sheets appeared. These climatic stresses triggered extinctions in plants and animals, both on land and in the oceans. By the early Oligocene (33 Ma), the Earth had a much cooler, more temperate climate, with a much lower diversity of organisms. Indeed, the Eocene-Oligocene transition marked the change from the global green­ house world of the Cretaceous and early Cenozoic to the glaciated ice house world of today. Despite the intense research interest in mass extinctions over the past two decades, the Eocene-Oligocene extinctions have been relatively under­ studied and misunderstood. While hundreds of papers have been published on the terminal Cretaceous extinction of dinosaurs and ammonites since the discovery of the iridium anomaly in 1980, only a few dozen articles have been published on the Eocene-Oligocene extinctions. Much of this work has now been invalidated by new data. In the enthusiasm to force the Eocene-Oligocene extinctions into the mold of the Cretaceous-Tertiary impact hypothesis and the periodic extinc­ tion hypothesis (Raup & Sepko ski 1984), a lot of misinformation has appeared. Typically, impact proponents treat the Eocene-Oligocene tran-

@article{doi101146annurevea22050194001045,
    author = "Prothero, Donald R.",
    title = "THE LATE EOCENE-OLIGOCENE EXTINCTIONS",
    year = "1994",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "The transition from the Eocene to the Oligocene Epochs, from about 40 to 30 Ma (million years ago), was the most significant interval in Earth history since the dinosaurs died out 65 Ma. From the warm, equable greenhouse climate of the early Eocene (a relict of the age of dinosaurs), the Earth experienced major climatic changes. Global temperature plum­ meted, and the first Antarctic sheets appeared. These climatic stresses triggered extinctions in plants and animals, both on land and in the oceans. By the early Oligocene (33 Ma), the Earth had a much cooler, more temperate climate, with a much lower diversity of organisms. Indeed, the Eocene-Oligocene transition marked the change from the global green­ house world of the Cretaceous and early Cenozoic to the glaciated ice house world of today. Despite the intense research interest in mass extinctions over the past two decades, the Eocene-Oligocene extinctions have been relatively under­ studied and misunderstood. While hundreds of papers have been published on the terminal Cretaceous extinction of dinosaurs and ammonites since the discovery of the iridium anomaly in 1980, only a few dozen articles have been published on the Eocene-Oligocene extinctions. Much of this work has now been invalidated by new data. In the enthusiasm to force the Eocene-Oligocene extinctions into the mold of the Cretaceous-Tertiary impact hypothesis and the periodic extinc­ tion hypothesis (Raup \& Sepko ski 1984), a lot of misinformation has appeared. Typically, impact proponents treat the Eocene-Oligocene tran-",
    url = "https://doi.org/10.1146/annurev.ea.22.050194.001045",
    doi = "10.1146/annurev.ea.22.050194.001045",
    openalex = "W2172893404",
    references = "doi10102990jb02015, doi101029jc082i027p03843, doi101029pa002i001p00001, doi101029pa002i003p00287, doi101126science2414866663, doi10113000167606197788969eotns20co2, doi1011300091761319920200569eoiseo23co2, doi101130gsab521, doi101306st6398c16, doi10151597814008629241"
}

Foreword: tribute to Robert Makela J. R. Horner Preface List of institutional abbreviations Introduction K. Carpenter, K. F. Hirsch, and J. R. Horner Part I. Distribution and History of Collecting: 1. Global distribution of dinosaur eggs, nests and baby skeletons K. Carpenter, and K. Alf 2. The discovery of dinosaur eggshells in nineteenth century France E. Buffetaut, and J. Le Loeuff Part II. Nests: 3. Dinosaur nesting patterns J. Moratalla, and J. Powell 4. Dinosaurian eggs from the Upper Cretaceous of Uruguay G. Faccio 5. Dinosaur egg laying and nesting in France R. Cousin, G. Breton, R. Fournier, and J-P. Watte 6. Late Maastrichtian dinosaur eggs from the Hateg Basin D. Grigorescu, D. Weishampel, D. Norman, M. Seclamen, M. Rusus, A. Baltres, and V. Teodorescu 7. Eggs and nests from the Cretaceous of Mongolia K. Mikhailov, K. Sabath, and S. Kurzanov 8. Comparative taphonomy of some dinosaur and extant bird colonial nesting grounds J. R. Horner 9. Predation of dinosaur nests by terrestrial crocodiles J. Kirkland Part III. Eggs: 10. Upper Jurassic eggshells from the western interior of North America K. F. Hirsch 11. Review of French dinosaur eggshells: eggshell morphology, structure, mineral and organic composition M. Vianey-Liaud, P. Mallan, O. Buscail, and C. Montgelard 12. Dinosaur eggs in China: on the structure and evolution of eggshells Z. Zi-Kui 13. Upper Cretaceous dinosaur eggs and nesting sites from the Deccan volcano-sedimentary province of peninsula India A. Sahni, S. K. Tandon, A. Jolly, S. Bajpai, A. Sood, and S. Srinivasan Part IV. Dinosaur Babies: 14. Life history syndromes, heterochrony, and the evolution of Dinosauria D. Weishampel, and J. R. Horner 15. Dinosaur reproduction in the fast lane: implication for size, success and extinction G. Paul 16. An embryonic Camarasaurus from the Upper Jurassic Morrison formation B. Britt, and B. Naylor 17. Upper Jurassic sauropod babies from the Morrison formation K. Carpenter, and J. McIntosh 18. Thermal travails of ornithopod nestings: implications for endothermy and insulation G. Paul 19. A baby Dryosaurus from the Upper Jurassic Morrison formation of Dinosaur National Monument K. Carpenter 20. An embryo of Camptosaurus from the Brushy Basin Member D. Chure, C. Turner, and F. Peterson 21. Ontogenetic growth of a new species of Hypacrosaurus J. R. Horner, and P. Currie 22. A nodosaurid scuteling from the Texas shore of the Western Interior Seaway L. Jacobs, D. Winkler, P. Murray, and J. Maurice 23. Dinosaur ontogeny and population structure: interpretations based on fossil footprints from North America M. Lockley 24. Summary and prospectus K. Carpenter, K. F. Hirsch, and J. R. Horner Taxonomic Index.

@book{openalexw1671792548,
    author = "Carpenter, Kenneth and Hirsch, Karl F. and Horner, John R.",
    title = "Dinosaur Eggs and Babies",
    year = "1994",
    abstract = "Foreword: tribute to Robert Makela J. R. Horner Preface List of institutional abbreviations Introduction K. Carpenter, K. F. Hirsch, and J. R. Horner Part I. Distribution and History of Collecting: 1. Global distribution of dinosaur eggs, nests and baby skeletons K. Carpenter, and K. Alf 2. The discovery of dinosaur eggshells in nineteenth century France E. Buffetaut, and J. Le Loeuff Part II. Nests: 3. Dinosaur nesting patterns J. Moratalla, and J. Powell 4. Dinosaurian eggs from the Upper Cretaceous of Uruguay G. Faccio 5. Dinosaur egg laying and nesting in France R. Cousin, G. Breton, R. Fournier, and J-P. Watte 6. Late Maastrichtian dinosaur eggs from the Hateg Basin D. Grigorescu, D. Weishampel, D. Norman, M. Seclamen, M. Rusus, A. Baltres, and V. Teodorescu 7. Eggs and nests from the Cretaceous of Mongolia K. Mikhailov, K. Sabath, and S. Kurzanov 8. Comparative taphonomy of some dinosaur and extant bird colonial nesting grounds J. R. Horner 9. Predation of dinosaur nests by terrestrial crocodiles J. Kirkland Part III. Eggs: 10. Upper Jurassic eggshells from the western interior of North America K. F. Hirsch 11. Review of French dinosaur eggshells: eggshell morphology, structure, mineral and organic composition M. Vianey-Liaud, P. Mallan, O. Buscail, and C. Montgelard 12. Dinosaur eggs in China: on the structure and evolution of eggshells Z. Zi-Kui 13. Upper Cretaceous dinosaur eggs and nesting sites from the Deccan volcano-sedimentary province of peninsula India A. Sahni, S. K. Tandon, A. Jolly, S. Bajpai, A. Sood, and S. Srinivasan Part IV. Dinosaur Babies: 14. Life history syndromes, heterochrony, and the evolution of Dinosauria D. Weishampel, and J. R. Horner 15. Dinosaur reproduction in the fast lane: implication for size, success and extinction G. Paul 16. An embryonic Camarasaurus from the Upper Jurassic Morrison formation B. Britt, and B. Naylor 17. Upper Jurassic sauropod babies from the Morrison formation K. Carpenter, and J. McIntosh 18. Thermal travails of ornithopod nestings: implications for endothermy and insulation G. Paul 19. A baby Dryosaurus from the Upper Jurassic Morrison formation of Dinosaur National Monument K. Carpenter 20. An embryo of Camptosaurus from the Brushy Basin Member D. Chure, C. Turner, and F. Peterson 21. Ontogenetic growth of a new species of Hypacrosaurus J. R. Horner, and P. Currie 22. A nodosaurid scuteling from the Texas shore of the Western Interior Seaway L. Jacobs, D. Winkler, P. Murray, and J. Maurice 23. Dinosaur ontogeny and population structure: interpretations based on fossil footprints from North America M. Lockley 24. Summary and prospectus K. Carpenter, K. F. Hirsch, and J. R. Horner Taxonomic Index.",
    openalex = "W1671792548"
}

Synopsis This chapter sets out to give a historical overview of the African rain forest from its origins, towards the end of the Cretaceous period. The areas around the Gulf of Guinea, in particular from Ivory Coast to Nigeria and especially Cameroon, Gabon and Congo, appear to have been already occupied at this time by wet tropical forest formations mainly composed of Angiosperms which were then becoming established. In the course of the Tertiary period the combined effect of the equator being situated further north than now and the development of the Antarctic ice cap favoured the development of wet tropical conditions over a large part of North Africa which in turn led to the extension of tropical forest to various sites on the shores of the Tethys Sea. There were probably at this time common taxa and similar vegetation patterns stretching from the Gulf of Guinea to the Tethys Sea. Towards the end of the Tertiary, the equator reached its present position and the northern hemisphere ice caps appeared, and these phenomena resulted in the disappearance of the forest formations spread across the north of Africa, and the concentration of these formations near the equatorial zone around the Gulf of Guinea and in the Congo–Zaïre basin. From 800 000 years ago onwards the marked glacial variations at middle and high latitudes in both hemispheres, with a periodicity of about 100 000 years determined by the orbital variations of the earth around the sun, lowered temperatures in equatorial areas and brought arid climates at times of maximum glacial extension. The most arid periods resulted in the fragmentation of the forest cover, and the forest biotopes and their biodiversity were preserved in a series of refugia. The lowering of temperatures also resulted in the extension of montane flora to low altitudes, with migration of montane flora and fauna between main mountain ranges. These compounded phenomena of isolation and migration, probably involving genie exchange, must have resulted in numerous speciation phenomena. Subsequently, such montane flora or fauna became isolated on mountain areas during periods of maximum warming, in the last instance in the course of the Holocene, when a vast forest cover became re-established from Guinea westwards, and to the East as far as the Lake Victoria area. The phases of maximum fragmentation, which appear to have been connected with only the coldest periods – in the last instance during the second part of isotopic stages 6 (from c. 160 to 130 000 years) and 2 (from c. 24 to 12000 years BP) – relate to less than 10% of the last 800 000 years, and the phases of maximum forest extension would likewise appear to be less than 10% of the period. The remaining 80–90% of the time relates to ‘intermediate situations’ which varied from period to period, and these intermediate extension situations seem to have been the norm over the larger part of the Quaternary, rather than the present situation which is closer to a situation of maximum extension.

@article{doi101017s0269727000006114,
    author = "Maley, Jean",
    title = "The African rain forest – main characteristics of changes in vegetation and climate from the Upper Cretaceous to the Quaternary",
    year = "1996",
    journal = "Proceedings of the Royal Society of Edinburgh Section B Biological Sciences",
    abstract = "Synopsis This chapter sets out to give a historical overview of the African rain forest from its origins, towards the end of the Cretaceous period. The areas around the Gulf of Guinea, in particular from Ivory Coast to Nigeria and especially Cameroon, Gabon and Congo, appear to have been already occupied at this time by wet tropical forest formations mainly composed of Angiosperms which were then becoming established. In the course of the Tertiary period the combined effect of the equator being situated further north than now and the development of the Antarctic ice cap favoured the development of wet tropical conditions over a large part of North Africa which in turn led to the extension of tropical forest to various sites on the shores of the Tethys Sea. There were probably at this time common taxa and similar vegetation patterns stretching from the Gulf of Guinea to the Tethys Sea. Towards the end of the Tertiary, the equator reached its present position and the northern hemisphere ice caps appeared, and these phenomena resulted in the disappearance of the forest formations spread across the north of Africa, and the concentration of these formations near the equatorial zone around the Gulf of Guinea and in the Congo–Zaïre basin. From 800 000 years ago onwards the marked glacial variations at middle and high latitudes in both hemispheres, with a periodicity of about 100 000 years determined by the orbital variations of the earth around the sun, lowered temperatures in equatorial areas and brought arid climates at times of maximum glacial extension. The most arid periods resulted in the fragmentation of the forest cover, and the forest biotopes and their biodiversity were preserved in a series of refugia. The lowering of temperatures also resulted in the extension of montane flora to low altitudes, with migration of montane flora and fauna between main mountain ranges. These compounded phenomena of isolation and migration, probably involving genie exchange, must have resulted in numerous speciation phenomena. Subsequently, such montane flora or fauna became isolated on mountain areas during periods of maximum warming, in the last instance in the course of the Holocene, when a vast forest cover became re-established from Guinea westwards, and to the East as far as the Lake Victoria area. The phases of maximum fragmentation, which appear to have been connected with only the coldest periods – in the last instance during the second part of isotopic stages 6 (from c. 160 to 130 000 years) and 2 (from c. 24 to 12000 years BP) – relate to less than 10\% of the last 800 000 years, and the phases of maximum forest extension would likewise appear to be less than 10\% of the period. The remaining 80–90\% of the time relates to ‘intermediate situations’ which varied from period to period, and these intermediate extension situations seem to have been the norm over the larger part of the Quaternary, rather than the present situation which is closer to a situation of maximum extension.",
    url = "https://doi.org/10.1017/s0269727000006114",
    doi = "10.1017/s0269727000006114",
    openalex = "W2113023952",
    references = "doi1010160031018282900852, doi1010160034666793900608, doi1010160198025483901334, doi1011300091761319920200569eoiseo23co2, doi105860choice260307"
}

Data on rocks from Spitsbergen and the equatorial sections of Italy and Slovenia indicate that the world's oceans became anoxic at both low and high paleolatitudes in the Late Permian. Such conditions may have been responsible for the mass extinction at this time. This event affected a wide range of shelf depths and extended into shallow water well above the storm wave base.

@article{doi101126science27252651155,
    author = "Wignall, Paul B. and Twitchett, Richard J.",
    title = "Oceanic Anoxia and the End Permian Mass Extinction",
    year = "1996",
    journal = "Science",
    abstract = "Data on rocks from Spitsbergen and the equatorial sections of Italy and Slovenia indicate that the world's oceans became anoxic at both low and high paleolatitudes in the Late Permian. Such conditions may have been responsible for the mass extinction at this time. This event affected a wide range of shelf depths and extended into shallow water well above the storm wave base.",
    url = "https://doi.org/10.1126/science.272.5265.1155",
    doi = "10.1126/science.272.5265.1155",
    openalex = "W1994510458",
    references = "doi1010160016703792903086, doi1010160031018292901825, doi101016003101829390068t, doi10102994pa01455, doi101126science26651891340, doi101126science267519477, doi101126science26952291413, doi1013060bda5a8916bd11d78645000102c1865d, doi101306212f89c22b2411d78648000102c1865d, doi1015159781400855414"
}

@book{doi101130spe307,
    author = "Ryder, G. and Fastovsky, David E. and Gärtner, Stefan",
    title = "The Cretaceous-Tertiary Event and Other Catastrophes in Earth History",
    year = "1996",
    booktitle = "Geological Society of America eBooks",
    url = "https://doi.org/10.1130/spe307",
    doi = "10.1130/spe307",
    openalex = "W565118425"
}

Abstract In the late Paleocene to early Eocene, deep sea benthic foraminifera suffered their only global extinction of the last 75 million years and diversity decreased worldwide by 30–50% in a few thousand years. At Maud Rise (Weddell Sea, Antarctica; Sites 689 and 690, palaeodepths 1100 m and 1900 m) and Walvis Ridge (Southeastern Atlantic, Sites 525 and 527, palaeodepths 1600 m and 3400 m) post-extinction faunas were low-diversity and high-dominance, but the dominant species differed by geographical location. At Maud Rise, post-extinction faunas were dominated by small, biserial and triserial species, while the large, thick-walled, long-lived deep sea species Nuttalides truempyi was absent. At Walvis Ridge, by contrast, they were dominated by long-lived species such as N. truempyi, with common to abundant small abyssaminid species. The faunal dominance patterns at the two locations thus suggest different post-extinction seafloor environments: increased flux of organic matter and possibly decreased oxygen levels at Maud Rise, decreased flux at Walvis Ridge. The species-richness remained very low for about 50 000 years, then gradually increased. The extinction was synchronous with a large, negative, short-term excursion of carbon and oxygen isotopes in planktonic and benthic foraminifera and bulk carbonate. The isotope excursions reached peak negative values in a few thousand years and values returned to preexcursion levels in about 50 000 years. The carbon isotope excursion was about −2‰ for benthic foraminifera at Walvis Ridge and Maud Rise, and about −4‰ for planktonic foraminifera at Maud Rise. At the latter sites vertical gradients thus decreased, possibly at least partially as a result of upwelling. The oxygen isotope excursion was about −1.5‰ for benthic foraminifera at Walvis Ridge and Maud Rise, −1‰ for planktonic foraminifera at Maud Rise. The rapid oxygen isotope excursion at a time when polar ice-sheets were absent or insignificant can be explained by an increase in temperature by 4–6°C of high latitude surface waters and deep waters world wide. The deep ocean temperature increase could have been caused by warming of surface waters at high latitudes and continued formation of the deep waters at these locations, or by a switch from dominant formation of deep waters at high latitudes to formation at lower latitudes. Benthic foraminiferal post-extinction biogeographical patterns favour the latter explanation. The short-term carbon isotope excursion occurred in deep and surface waters, and in soil concretions and mammal teeth in the continental record. It is associated with increased CaCO 3 -dissolution over a wide depth range in the oceans, suggesting that a rapid transfer of isotopically light carbon from lithosphere or biosphere into the ocean-atmosphere system may have been involved. The rapidity of the initiation of the excursion (a few thousand years) and its short duration (50 000 years) suggest that such a transfer was probably not caused by changes in the ratio of organic carbon to carbonate deposition or erosion. Transfer of carbon from the terrestrial biosphere was probably not the cause, because it would require a much larger biosphere destruction than at the end of the Cretaceous, in conflict with the fossil record. It is difficult to explain the large shift by rapid emission into the atmosphere of volcanogenic CO 2, although huge subaerial plateau basalt eruptions occurred at the time in the northern Atlantic. Probably a complex combination of processes and feedback was involved, including volcanogenic emission of CO 2, changing circulation patterns, changing productivity in the oceans and possibly on land, and changes in the relative size of the oceanic and atmospheric carbon reservoirs.

@article{doi101144gslsp19961010120,
    author = "Thomas, Ellen and Shackleton, Nicholas J",
    title = "The Paleocene-Eocene benthic foraminiferal extinction and stable isotope anomalies",
    year = "1996",
    journal = "Geological Society London Special Publications",
    abstract = "Abstract In the late Paleocene to early Eocene, deep sea benthic foraminifera suffered their only global extinction of the last 75 million years and diversity decreased worldwide by 30–50\% in a few thousand years. At Maud Rise (Weddell Sea, Antarctica; Sites 689 and 690, palaeodepths 1100 m and 1900 m) and Walvis Ridge (Southeastern Atlantic, Sites 525 and 527, palaeodepths 1600 m and 3400 m) post-extinction faunas were low-diversity and high-dominance, but the dominant species differed by geographical location. At Maud Rise, post-extinction faunas were dominated by small, biserial and triserial species, while the large, thick-walled, long-lived deep sea species Nuttalides truempyi was absent. At Walvis Ridge, by contrast, they were dominated by long-lived species such as N. truempyi, with common to abundant small abyssaminid species. The faunal dominance patterns at the two locations thus suggest different post-extinction seafloor environments: increased flux of organic matter and possibly decreased oxygen levels at Maud Rise, decreased flux at Walvis Ridge. The species-richness remained very low for about 50 000 years, then gradually increased. The extinction was synchronous with a large, negative, short-term excursion of carbon and oxygen isotopes in planktonic and benthic foraminifera and bulk carbonate. The isotope excursions reached peak negative values in a few thousand years and values returned to preexcursion levels in about 50 000 years. The carbon isotope excursion was about −2‰ for benthic foraminifera at Walvis Ridge and Maud Rise, and about −4‰ for planktonic foraminifera at Maud Rise. At the latter sites vertical gradients thus decreased, possibly at least partially as a result of upwelling. The oxygen isotope excursion was about −1.5‰ for benthic foraminifera at Walvis Ridge and Maud Rise, −1‰ for planktonic foraminifera at Maud Rise. The rapid oxygen isotope excursion at a time when polar ice-sheets were absent or insignificant can be explained by an increase in temperature by 4–6°C of high latitude surface waters and deep waters world wide. The deep ocean temperature increase could have been caused by warming of surface waters at high latitudes and continued formation of the deep waters at these locations, or by a switch from dominant formation of deep waters at high latitudes to formation at lower latitudes. Benthic foraminiferal post-extinction biogeographical patterns favour the latter explanation. The short-term carbon isotope excursion occurred in deep and surface waters, and in soil concretions and mammal teeth in the continental record. It is associated with increased CaCO 3 -dissolution over a wide depth range in the oceans, suggesting that a rapid transfer of isotopically light carbon from lithosphere or biosphere into the ocean-atmosphere system may have been involved. The rapidity of the initiation of the excursion (a few thousand years) and its short duration (50 000 years) suggest that such a transfer was probably not caused by changes in the ratio of organic carbon to carbonate deposition or erosion. Transfer of carbon from the terrestrial biosphere was probably not the cause, because it would require a much larger biosphere destruction than at the end of the Cretaceous, in conflict with the fossil record. It is difficult to explain the large shift by rapid emission into the atmosphere of volcanogenic CO 2, although huge subaerial plateau basalt eruptions occurred at the time in the northern Atlantic. Probably a complex combination of processes and feedback was involved, including volcanogenic emission of CO 2, changing circulation patterns, changing productivity in the oceans and possibly on land, and changes in the relative size of the oceanic and atmospheric carbon reservoirs.",
    url = "https://doi.org/10.1144/gsl.sp.1996.101.01.20",
    doi = "10.1144/gsl.sp.1996.101.01.20",
    openalex = "W2161313234",
    references = "doi101016003101829290096n, doi1010160377839884900021, doi101029pa002i003p00287, doi102110pec9554"
}

A comprehensive analysis of volatiles in the Chicxulub impact strongly supports the hypothesis that impact-generated sulfate aerosols caused over a decade of global cooling, acid rain, and disruption of ocean circulation, which contributed to the mass extinction at the Cretaceous/Tertiary (K/T) boundary. The crater size, meteoritic content of the K/T boundary clay, and impact models indicate that the Chicxulub crater was formed by a short period comet or an asteroid impact that released 0.7-3.4 x 10(31) ergs of energy. Impact models and experiments combined with estimates of volatiles in the projectile and target rocks predict that over 200 gigatons (Gt) each of SO2 and water vapor, and over 500 Gt of CO2, were globally distributed in the stratosphere by the impact. Additional volatiles may have been produced on a global or regional scale that formed sulfate aerosols rapidly in cooler parts of the vapor plume, causing an early, intense pulse of sulfuric acid rain. Estimates of the conversion rate of stratospheric SO2 and water vapor to sulfate aerosol, based on volcanic production of sulfate aerosols, coupled with calculations of diffusion, coagulation, and sedimentation, demonstrate that the 200 Gt stratospheric SO2 and water vapor reservoir would produce sulfate aerosols for 12 years. These sulfate aerosols caused a second pulse of acid rain that was global. Radiative transfer modeling of the aerosol clouds demonstrates (1) that if the initial rapid pulse of sulfate aerosols was global, photosynthesis may have been shut down for 6 months and (2) that for the second prolonged aerosol cloud, solar transmission dropped 80% by the end of first year and remained 50% below normal for 9 years. As a result, global average surface temperatures probably dropped between 5 degrees and 31 degrees K, suggesting that global near-freezing conditions may have been reached. Impact-generated CO2 caused less than 1 degree K greenhouse warming and therefore was insignificant compare to the sulfate cooling. The magnitude of sulfate cooling depends largely upon the rate of ocean mixing as surface waters cool, sink, and are replaced by upwelling of deep ocean water. This upwelling apparently drastically altered ocean stratification and circulation, which may explain the global collapse of the delta 13C gradient between surface and deep ocean waters at the K/T boundary.

@article{doi10102997je01743,
    author = "Pope, Kevin and Baines, Kevin H. and Ocampo, Adriana and Ivanov, B. A.",
    title = "Energy, volatile production, and climatic effects of the Chicxulub Cretaceous/Tertiary impact",
    year = "1997",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "A comprehensive analysis of volatiles in the Chicxulub impact strongly supports the hypothesis that impact-generated sulfate aerosols caused over a decade of global cooling, acid rain, and disruption of ocean circulation, which contributed to the mass extinction at the Cretaceous/Tertiary (K/T) boundary. The crater size, meteoritic content of the K/T boundary clay, and impact models indicate that the Chicxulub crater was formed by a short period comet or an asteroid impact that released 0.7-3.4 x 10(31) ergs of energy. Impact models and experiments combined with estimates of volatiles in the projectile and target rocks predict that over 200 gigatons (Gt) each of SO2 and water vapor, and over 500 Gt of CO2, were globally distributed in the stratosphere by the impact. Additional volatiles may have been produced on a global or regional scale that formed sulfate aerosols rapidly in cooler parts of the vapor plume, causing an early, intense pulse of sulfuric acid rain. Estimates of the conversion rate of stratospheric SO2 and water vapor to sulfate aerosol, based on volcanic production of sulfate aerosols, coupled with calculations of diffusion, coagulation, and sedimentation, demonstrate that the 200 Gt stratospheric SO2 and water vapor reservoir would produce sulfate aerosols for 12 years. These sulfate aerosols caused a second pulse of acid rain that was global. Radiative transfer modeling of the aerosol clouds demonstrates (1) that if the initial rapid pulse of sulfate aerosols was global, photosynthesis may have been shut down for 6 months and (2) that for the second prolonged aerosol cloud, solar transmission dropped 80\% by the end of first year and remained 50\% below normal for 9 years. As a result, global average surface temperatures probably dropped between 5 degrees and 31 degrees K, suggesting that global near-freezing conditions may have been reached. Impact-generated CO2 caused less than 1 degree K greenhouse warming and therefore was insignificant compare to the sulfate cooling. The magnitude of sulfate cooling depends largely upon the rate of ocean mixing as surface waters cool, sink, and are replaced by upwelling of deep ocean water. This upwelling apparently drastically altered ocean stratification and circulation, which may explain the global collapse of the delta 13C gradient between surface and deep ocean waters at the K/T boundary.",
    url = "https://doi.org/10.1029/97je01743",
    doi = "10.1029/97je01743",
    openalex = "W2066886748",
    references = "alvarez1980extraterrestrial, doi1010160016703789901506, doi101038359819a0, doi101111j194551001995tb01113x, doi101126science21545391501, doi101126science22246301283, doi101126science23547931156, doi101126science2555043423, doi1011300091761319910190867ccapct23co2, doi1011300091761319920200099tbdwcu23co2, doi1011300091761319950230873ynssia23co2, doi101130spe247p155, doi1017159caj1991847309, doi105860choice330281, openalexw2139291338"
}

Abstract Why do mass extinctions occur? The demise of the dinosaurs has been discussed exhaustively, but has never been out into the context of other extinction events. This is the first systematic review of the mass extinctions of all organisms, plant and animal, terrestrial and marine, that have occurred in the history of life. This includes the major crisis 250 million years ago which nearly wiped out all life on Earth. By examining current paleontological, geological, and sedimentological evidence of environmental changes, the cases for explanations based on climate change, marine regressions, asteroid or comet impact, anoxia, and volcanic eruptions are all critically evaluated.

@book{doi101093oso97801985491780010001,
    author = "Hallam, A. and Wignall, Paul B.",
    title = "Mass Extinctions and Their Aftermath",
    year = "1997",
    abstract = "Abstract Why do mass extinctions occur? The demise of the dinosaurs has been discussed exhaustively, but has never been out into the context of other extinction events. This is the first systematic review of the mass extinctions of all organisms, plant and animal, terrestrial and marine, that have occurred in the history of life. This includes the major crisis 250 million years ago which nearly wiped out all life on Earth. By examining current paleontological, geological, and sedimentological evidence of environmental changes, the cases for explanations based on climate change, marine regressions, asteroid or comet impact, anoxia, and volcanic eruptions are all critically evaluated.",
    url = "https://doi.org/10.1093/oso/9780198549178.001.0001",
    doi = "10.1093/oso/9780198549178.001.0001",
    openalex = "W4388328712"
}

The extent of terrestrial vertebrate extinctions at the end of the Cretaceous is poorly understood, and estimates have ranged from a mass extinction to limited extinctions of specific groups. Molecular and paleontological data demonstrate that modern bird orders started diverging in the Early Cretaceous; at least 22 avian lineages of modern birds cross the Cretaceous-Tertiary boundary. Data for several other terrestrial vertebrate groups indicate a similar pattern of survival and, taken together, favor incremental changes during a Cretaceous diversification of birds and mammals rather than an explosive radiation in the Early Tertiary.

@article{doi101126science27553031109,
    author = "Cooper, Alan and Penny, David",
    title = "Mass Survival of Birds Across the Cretaceous- Tertiary Boundary: Molecular Evidence",
    year = "1997",
    journal = "Science",
    abstract = "The extent of terrestrial vertebrate extinctions at the end of the Cretaceous is poorly understood, and estimates have ranged from a mass extinction to limited extinctions of specific groups. Molecular and paleontological data demonstrate that modern bird orders started diverging in the Early Cretaceous; at least 22 avian lineages of modern birds cross the Cretaceous-Tertiary boundary. Data for several other terrestrial vertebrate groups indicate a similar pattern of survival and, taken together, favor incremental changes during a Cretaceous diversification of birds and mammals rather than an explosive radiation in the Early Tertiary.",
    url = "https://doi.org/10.1126/science.275.5303.1109",
    doi = "10.1126/science.275.5303.1109",
    openalex = "W2091114915",
    references = "doi10129879780300237856"
}

Mass extinctions are recognized through the study of fossil groups across event horizons, and from analyses of long-term trends in taxonomic richness and diversity. Both approaches have inherent flaws, and data that once seemed reliable can be readily superseded by the discovery of new fossils and/or the application of new analytical techniques. Herein the current state of the Cretaceous-Tertiary (K-T) biostratigraphical record is reviewed for most major fossil clades, including: calcareous nannoplankton, dinoflagellates, diatoms, radiolaria, foraminifera, ostracodes, scleractinian corals, bryozoans, brachio-pods, molluscs, echinoderms, fish, amphibians, reptiles and terrestrial plants (macrofossils and palynomorphs). These reviews take account of possible biasing factors in the fossil record in order to extract the most comprehensive picture of the K-T biotic crisis available. Results suggest that many faunal and floral groups (ostracodes, bryozoa, ammonite cephalopods, bivalves, archosaurs) were in decline throughout the latest Maastrichtian while others (diatoms, radiolaria, benthic foraminifera, brachiopods, gastropods, fish, amphibians, lepidosaurs, terrestrial plants) passed through the K-T event horizon with only minor taxonomic richness and/or diversity changes. A few microfossil groups (calcareous nannoplankton, dinoflagellates, planktonic foraminifera) did experience a turnover of varying magnitudes in the latest Maastrichtian-earliest Danian. However, many of these turnovers, along with changes in ecological dominance patterns among benthic foraminifera, began in the latest Maastrichtian. Improved taxonomic estimates of the overall pattern and magnitude of the K-T extinction event must await the development of more reliable systematic and phylogenetic data for all Upper Cretaceous clades.

@article{doi101144gsjgs15420265,
    author = "MacLeod, Norman and Rawson, Peter F. and Forey, Peter L. and Banner, F. T. and BouDagher‐Fadel, Marcelle K. and Bown, Paul R. and Burnett, J. A. and Chambers, Paul and Culver, Stephen J. and Evans, Susan E. and Jeffery, C. S. and Kaminski, Michael A. and Lord, Alan and MILNER, A. C. and Milner, Andrew R. and Morris, Noel J. and Owen, Ellie and Rosen, Brian and Smith, A. B. and Taylor, Paul D. and Urquhart, Elspeth and Young, J. R.",
    title = "The Cretaceous-Tertiary biotic transition",
    year = "1997",
    journal = "Journal of the Geological Society",
    abstract = "Mass extinctions are recognized through the study of fossil groups across event horizons, and from analyses of long-term trends in taxonomic richness and diversity. Both approaches have inherent flaws, and data that once seemed reliable can be readily superseded by the discovery of new fossils and/or the application of new analytical techniques. Herein the current state of the Cretaceous-Tertiary (K-T) biostratigraphical record is reviewed for most major fossil clades, including: calcareous nannoplankton, dinoflagellates, diatoms, radiolaria, foraminifera, ostracodes, scleractinian corals, bryozoans, brachio-pods, molluscs, echinoderms, fish, amphibians, reptiles and terrestrial plants (macrofossils and palynomorphs). These reviews take account of possible biasing factors in the fossil record in order to extract the most comprehensive picture of the K-T biotic crisis available. Results suggest that many faunal and floral groups (ostracodes, bryozoa, ammonite cephalopods, bivalves, archosaurs) were in decline throughout the latest Maastrichtian while others (diatoms, radiolaria, benthic foraminifera, brachiopods, gastropods, fish, amphibians, lepidosaurs, terrestrial plants) passed through the K-T event horizon with only minor taxonomic richness and/or diversity changes. A few microfossil groups (calcareous nannoplankton, dinoflagellates, planktonic foraminifera) did experience a turnover of varying magnitudes in the latest Maastrichtian-earliest Danian. However, many of these turnovers, along with changes in ecological dominance patterns among benthic foraminifera, began in the latest Maastrichtian. Improved taxonomic estimates of the overall pattern and magnitude of the K-T extinction event must await the development of more reliable systematic and phylogenetic data for all Upper Cretaceous clades.",
    url = "https://doi.org/10.1144/gsjgs.154.2.0265",
    doi = "10.1144/gsjgs.154.2.0265",
    openalex = "W2111194718",
    references = "alvarez1980extraterrestrial, doi1010160377839888900023, doi101017s0022336000029486, doi101017s0022336000061321, doi101017s0022336000062223, doi101073pnas813801, doi101111j136531211990tb00103x, doi101126science20844481095, doi101126science23547931156, doi1011300016760619951071164mlccot23co2, doi101130spe190p291, doi1012019781003077831, doi102110pec9504, doi102110pec95040129, doi1023071483846, doi1023072259561, doi1023073514632, kier1974evolutionary, kitchell1986biological, kitchellNonebiological, openalexw1599677799, sloan1986gradual"
}

@article{doi101016s0012825299000550,
    author = "Hallam, A.",
    title = "Mass extinctions and sea-level changes",
    year = "1999",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/s0012-8252(99)00055-0",
    doi = "10.1016/s0012-8252(99)00055-0",
    openalex = "W1997469183",
    references = "alvarez1980extraterrestrial, doi10100797836427859317, doi1010160031018292901825, doi101016s0031018298000170, doi101016s003101829800056x, doi101017s0016756898008917, doi101017s0094837300008708, doi101029jb094ib06p07685, doi101038353225a0, doi101093oso97801985771880010001, doi101126science23547931156, doi101126science23848311237, doi101126science27252651155, doi101126science2735274452, doi101126science2845414616, doi10113000167606198596567defie20co2, doi101130spe190p329, doi101130spe89p63, doi101144gsjgs13620175, doi101144gsjgs15420265, doi101144gsjgs15450773, doi1023073515466, doi102475ajs2882101, openalexw597633443"
}

▪ Abstract The Chicxulub crater ejecta stratigraphy is reviewed, in the context of the stratigraphy of underlying and overlying rock sequences. The ejecta sequence is regionally grouped in (a) thick polymict and monomict breccia sequences inside the crater and within 300 km from the rim of the crater known from drill holes in and close to the breater, and exposures near the border of Yucatan and Belize; (b) Gulf of Mexico region, <2500 m from the crater, with up to 9 m thick, complex, tsunami-wave influenced, tektite-bearing sequences in shallow marine (<500 m deep) environments and tektite bearing, decimeter thick gravity-flow deposits in deep water sites; (c) an intermediate region between 2500 and 4000 km from the crater where centimeter thick, tektite-bearing layers occur, and (d) a global distal region with a millimeter thin ejecta layer. The distal ejecta layer is characterized by sub-millimeter sized microkrystites, often rich in Ni-rich spinels and (altered) clinopyroxene. Wherever present, the ejecta layers mark exactly the sudden mass-mortality horizon of the K/T boundary. What exactly caused the mass mortality is still uncertain, but it appears the main event leading to the K/T mass extinctions.

@article{doi101146annurevearth27175,
    author = "Smit, Jan",
    title = "THE GLOBAL STRATIGRAPHY OF THE CRETACEOUS-TERTIARY BOUNDARY IMPACT EJECTA",
    year = "1999",
    journal = "Annual Review of Earth and Planetary Sciences",
    abstract = "▪ Abstract The Chicxulub crater ejecta stratigraphy is reviewed, in the context of the stratigraphy of underlying and overlying rock sequences. The ejecta sequence is regionally grouped in (a) thick polymict and monomict breccia sequences inside the crater and within 300 km from the rim of the crater known from drill holes in and close to the breater, and exposures near the border of Yucatan and Belize; (b) Gulf of Mexico region, <2500 m from the crater, with up to 9 m thick, complex, tsunami-wave influenced, tektite-bearing sequences in shallow marine (<500 m deep) environments and tektite bearing, decimeter thick gravity-flow deposits in deep water sites; (c) an intermediate region between 2500 and 4000 km from the crater where centimeter thick, tektite-bearing layers occur, and (d) a global distal region with a millimeter thin ejecta layer. The distal ejecta layer is characterized by sub-millimeter sized microkrystites, often rich in Ni-rich spinels and (altered) clinopyroxene. Wherever present, the ejecta layers mark exactly the sudden mass-mortality horizon of the K/T boundary. What exactly caused the mass mortality is still uncertain, but it appears the main event leading to the K/T mass extinctions.",
    url = "https://doi.org/10.1146/annurev.earth.27.1.75",
    doi = "10.1146/annurev.earth.27.1.75",
    openalex = "W2116735545",
    references = "doi1010160012821x9090115e, doi1010160012821x9190113v, doi101126science2244651867, doi101126science25250131690, doi101126science2575072954, doi1011300091761319910190867ccapct23co2, doi1011300091761319920200099tbdwcu23co2, doi102110pec74200094"
}

This is a systematic review of the major mass extinctions in the history of life. It covers all groups of organisms - plant, animal, terrestrial, and marine - that have become extinct alongside the geological and sedimentological evidence for environmental changes during the biotic crises. All proposed extinction mechanisms - climate change, meteorite impact, volcanisms - are critically assessed. In this text the demise of the dinosaurs is put into the proper context of other extinction events. This book is intended for undergraduates in Europe and graduate students in the US, studying geology, palaeontology, or evolutionary biology, and their teachers. It should also be of interest to research scientists in adjacent subjects.

@article{doi1023073515466,
    author = "Marshall, Charles R. and Hallam, A. and Wignall, Paul B.",
    title = "Mass Extinctions and Their Aftermath",
    year = "1999",
    journal = "Palaios",
    abstract = "This is a systematic review of the major mass extinctions in the history of life. It covers all groups of organisms - plant, animal, terrestrial, and marine - that have become extinct alongside the geological and sedimentological evidence for environmental changes during the biotic crises. All proposed extinction mechanisms - climate change, meteorite impact, volcanisms - are critically assessed. In this text the demise of the dinosaurs is put into the proper context of other extinction events. This book is intended for undergraduates in Europe and graduate students in the US, studying geology, palaeontology, or evolutionary biology, and their teachers. It should also be of interest to research scientists in adjacent subjects.",
    url = "https://doi.org/10.2307/3515466",
    doi = "10.2307/3515466",
    openalex = "W2025737227"
}

Foreword Claude Allege Preface Preface to the English translation 1. Mass extinctions 2. An asteroid impact 3. From the roof of the world to the Deccan traps 4. The volcanic scenario 5. Plumes and hotspots 6. A remarkable correlation 7. Nemesis or Shiva? 8. Chicxulub 9. Controversy and coincidence 10. Improbable catastrophes and the flukes of evolution Index.

@article{doi105860choice375113,
    title = "Evolutionary catastrophes: the science of mass extinction",
    year = "2000",
    journal = "Choice Reviews Online",
    abstract = "Foreword Claude Allege Preface Preface to the English translation 1. Mass extinctions 2. An asteroid impact 3. From the roof of the world to the Deccan traps 4. The volcanic scenario 5. Plumes and hotspots 6. A remarkable correlation 7. Nemesis or Shiva? 8. Chicxulub 9. Controversy and coincidence 10. Improbable catastrophes and the flukes of evolution Index.",
    url = "https://doi.org/10.5860/choice.37-5113",
    doi = "10.5860/choice.37-5113",
    openalex = "W1601910138"
}

@article{doi101016s0012825200000374,
    author = "Wignall, Paul B.",
    title = "Large igneous provinces and mass extinctions",
    year = "2001",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/s0012-8252(00)00037-4",
    doi = "10.1016/s0012-8252(00)00037-4",
    openalex = "W2079852953",
    references = "alvarez1980extraterrestrial, doi101007bf01821208, doi1010160012821x82900073, doi1010160012821x90900726, doi1010160031018292901825, doi1010160031018293901286, doi1010160031018294903468, doi101016s0009254197001599, doi101016s0012825299000550, doi101016s0031018298001175, doi101017s0094837300008708, doi1010291998rg000054, doi10102993rg02508, doi10102994jb01889, doi10102995pa02087, doi101029gm100, doi101029jb094ib06p07685, doi101038227930a0, doi101038326143a0, doi101038353225a0, doi101073pnas813801, doi101093oso97801985491780010001, doi101126science11536548, doi101126science20844481095, doi101126science23547931156, doi101126science2414866663, doi101126science2464926103, doi101126science2675199852, doi101126science27252651155, doi101126science28253972241, doi101126science2845414616, doi1011300091761319950230495ejmeag23co2, doi1011300091761320020300251tameat20co2, doi101146annurevearth26181, doi1023073515466, loper1988a"
}

Mid‐Cretaceous (Barremian‐Turonian) plankton preserved in deep‐sea marl, organic‐rich shale, and pelagic carbonate hold an important record of how the marine biosphere responded to short‐ and long‐term changes in the ocean‐climate system. Oceanic anoxic events (OAEs) were short‐lived episodes of organic carbon burial that are distinguished by their widespread distribution as discrete beds of black shale and/or pronounced carbon isotopic excursions. OAE1a in the early Aptian (∼120.5 Ma) and OAE2 at the Cenomanian/Turonian boundary (∼93.5 Ma) were global in their distribution and associated with heightened marine productivity. OAE1b spans the Aptian/Albian boundary (∼113–109 Ma) and represents a protracted interval of dysoxia with multiple discrete black shales across parts of Tethys (including Mexico), while OAE1d developed across eastern and western Tethys and in other locales during the latest Albian (∼99.5 Ma). Mineralized plankton experienced accelerated rates of speciation and extinction at or near the major Cretaceous OAEs, and strontium isotopic evidence suggests a possible link to times of rapid oceanic plateau formation and/or increased rates of ridge crest volcanism. Elevated levels of trace metals in OAE1a and OAE2 strata suggest that marine productivity may have been facilitated by increased availability of dissolved iron. The association of plankton turnover and carbon isotopic excursions with each of the major OAEs, despite the variable geographic distribution of black shale accumulation, points to widespread changes in the ocean‐climate system. Ocean crust production and hydrothermal activity increased in the late Aptian. Faster spreading rates [and/or increased ridge length] drove a long‐term (Albian–early Turonian) rise in sea level and CO 2 ‐induced global warming. Changes in ocean circulation, water column stratification, and nutrient partitioning lead to a reorganization of plankton community structure and widespread carbonate (chalk) deposition during the Late Cretaceous. We conclude that there were important linkages between submarine volcanism, plankton evolution, and the cycling of carbon through the marine biosphere.

@article{doi1010292001pa000623,
    author = "Leckie, R. Mark and Bralower, Timothy J. and Cashman, Richard",
    title = "Oceanic anoxic events and plankton evolution: Biotic response to tectonic forcing during the mid‐Cretaceous",
    year = "2002",
    journal = "Paleoceanography",
    abstract = "Mid‐Cretaceous (Barremian‐Turonian) plankton preserved in deep‐sea marl, organic‐rich shale, and pelagic carbonate hold an important record of how the marine biosphere responded to short‐ and long‐term changes in the ocean‐climate system. Oceanic anoxic events (OAEs) were short‐lived episodes of organic carbon burial that are distinguished by their widespread distribution as discrete beds of black shale and/or pronounced carbon isotopic excursions. OAE1a in the early Aptian (∼120.5 Ma) and OAE2 at the Cenomanian/Turonian boundary (∼93.5 Ma) were global in their distribution and associated with heightened marine productivity. OAE1b spans the Aptian/Albian boundary (∼113–109 Ma) and represents a protracted interval of dysoxia with multiple discrete black shales across parts of Tethys (including Mexico), while OAE1d developed across eastern and western Tethys and in other locales during the latest Albian (∼99.5 Ma). Mineralized plankton experienced accelerated rates of speciation and extinction at or near the major Cretaceous OAEs, and strontium isotopic evidence suggests a possible link to times of rapid oceanic plateau formation and/or increased rates of ridge crest volcanism. Elevated levels of trace metals in OAE1a and OAE2 strata suggest that marine productivity may have been facilitated by increased availability of dissolved iron. The association of plankton turnover and carbon isotopic excursions with each of the major OAEs, despite the variable geographic distribution of black shale accumulation, points to widespread changes in the ocean‐climate system. Ocean crust production and hydrothermal activity increased in the late Aptian. Faster spreading rates [and/or increased ridge length] drove a long‐term (Albian–early Turonian) rise in sea level and CO 2 ‐induced global warming. Changes in ocean circulation, water column stratification, and nutrient partitioning lead to a reorganization of plankton community structure and widespread carbonate (chalk) deposition during the Late Cretaceous. We conclude that there were important linkages between submarine volcanism, plankton evolution, and the cycling of carbon through the marine biosphere.",
    url = "https://doi.org/10.1029/2001pa000623",
    doi = "10.1029/2001pa000623",
    openalex = "W1620286502",
    references = "boudagherfadel1997the, doi1010079781461235446, doi1010079789401748414, doi1010160012825273900925, doi1010160012825283900016, doi1010160025322771900533, doi1010160031018294903468, doi1010160195667188900031, doi1010160377839883900105, doi101017cbo9780511628948, doi101017s0094837300005352, doi101017s0094837300012793, doi101017s0094837300013178, doi10102993pa03266, doi10102993rg02508, doi10102994jb01889, doi101029pa001i004p00495, doi101029pa005i001p00001, doi10103822941, doi101038298841a0, doi101038321739a0, doi101038331341a0, doi101038333547a0, doi101126science2815374200, doi1011300016760619951071164mlccot23co2, doi1011300091761320020300123dsproe20co2, doi101144gsjgs13720171, doi101144gslsp19870260125, doi102110pec77250019, doi102110pec88010071, doi102110pec88010183, doi1023071485903, doi102973dsdpproc291171975, doi102973dsdpproc431401979, doi103354meps010257, doi105860choice265651, gradstein1998the, openalexw1491290751, openalexw2106559152"
}

Abstract Elongate and asymmetric eggs of the oospecies Prismatoolithus levis occur regularly in the Upper Cretaceous Two Medicine Formation of western Montana. These eggs had previously been assigned to the ornithischian Orodromeus makelai, for both juvenile and adult remains are typically associated with these eggs. Reexamination of the embryos shows them to exhibit at least 24 apomorphies of the clades Dinosauria, Theropoda and Paraves. The embryos also display a pneumatic quadrate, closely placed basal tubera, a high tooth count, a metatarsal II much narrower than IV and a strongly constricted metatarsal III, all possible synapomorphies of the Troodontidae. Presence of large basal tubera and a broadly rounded anterior border of the maxillary fenestra permit assignment to Troodon formosus. Most but not all bones appear ossified, suggesting a developmental level comparable to stages 35–38 of avian embryos and a time approaching hatching. Embryos show a consistent level of development from one egg to another indicating synchronous hatching of the clutch. Embryonic Troodon exhibit long distal segments and radically different hindlimb proportions in comparison to adults. Orodromeus and other small vertebrate remains associated with Troodon egg horizons may represent prey of the adults during egg-laying and brooding. Troodon eggs show several aspects either shared or convergent with some birds, and further demonstrate the close relationship of Troodontidae and Aves. These features include: asymmetric egg form, non-branching angusticanaliculate pores, distinct structural differentiation of the mammillary and overlying prismatic layer, barrel-shaped mammillary cones with a blocky calcite cleavage, and prismatic structure visible throughout the second structural layer.

@article{doi1016710272463420020220564eaeftc20co2,
    author = "Varricchio, David J. and Horner, John R. and Jackson, Frankie D.",
    title = "Embryos and eggs for the Cretaceous theropod dinosaur Troodon formosus",
    year = "2002",
    journal = "Journal of Vertebrate Paleontology",
    abstract = "Abstract Elongate and asymmetric eggs of the oospecies Prismatoolithus levis occur regularly in the Upper Cretaceous Two Medicine Formation of western Montana. These eggs had previously been assigned to the ornithischian Orodromeus makelai, for both juvenile and adult remains are typically associated with these eggs. Reexamination of the embryos shows them to exhibit at least 24 apomorphies of the clades Dinosauria, Theropoda and Paraves. The embryos also display a pneumatic quadrate, closely placed basal tubera, a high tooth count, a metatarsal II much narrower than IV and a strongly constricted metatarsal III, all possible synapomorphies of the Troodontidae. Presence of large basal tubera and a broadly rounded anterior border of the maxillary fenestra permit assignment to Troodon formosus. Most but not all bones appear ossified, suggesting a developmental level comparable to stages 35–38 of avian embryos and a time approaching hatching. Embryos show a consistent level of development from one egg to another indicating synchronous hatching of the clutch. Embryonic Troodon exhibit long distal segments and radically different hindlimb proportions in comparison to adults. Orodromeus and other small vertebrate remains associated with Troodon egg horizons may represent prey of the adults during egg-laying and brooding. Troodon eggs show several aspects either shared or convergent with some birds, and further demonstrate the close relationship of Troodontidae and Aves. These features include: asymmetric egg form, non-branching angusticanaliculate pores, distinct structural differentiation of the mammillary and overlying prismatic layer, barrel-shaped mammillary cones with a blocky calcite cleavage, and prismatic structure visible throughout the second structural layer.",
    url = "https://doi.org/10.1671/0272-4634(2002)022[0564:eaeftc]2.0.co;2",
    doi = "10.1671/0272-4634(2002)022[0564:eaeftc]2.0.co;2",
    openalex = "W2181267725",
    references = "wilson1985stenonychosaurus"
}

@article{doi101016s0012821x03003479,
    author = "Kamo, Sandra L. and Czamanske, Gerald K. and Amelin, Yuri and Fedorenko, V. A. and Davis, Donald W. and Trofimov, V.R",
    title = "Rapid eruption of Siberian flood-volcanic rocks and evidence for coincidence with the Permian–Triassic boundary and mass extinction at 251 Ma",
    year = "2003",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/s0012-821x(03)00347-9",
    doi = "10.1016/s0012-821x(03)00347-9",
    openalex = "W2109153037",
    references = "doi1011300091761319910190867ccapct23co2"
}

Terrestrial climates near the time of the end-Cretaceous mass extinction are poorly known, limiting understanding of environmentally driven changes in biodiversity that occurred before bolide impact. We estimate paleotemperatures for the last approximately 1.1 million years of the Cretaceous (approximately 66.6-65.5 million years ago, Ma) by using fossil plants from North Dakota and employ paleomagnetic stratigraphy to correlate the results to foraminiferal paleoclimatic data from four middle- and high-latitude sites. Both plants and foraminifera indicate warming near 66.0 Ma, a warming peak from approximately 65.8 to 65.6 Ma, and cooling near 65.6 Ma, suggesting that these were global climate shifts. The warming peak coincides with the immigration of a thermophilic flora, maximum plant diversity, and the poleward range expansion of thermophilic foraminifera. Plant data indicate the continuation of relatively cool temperatures across the Cretaceous-Paleogene boundary; there is no indication of a major warming immediately after the boundary as previously reported. Our temperature proxies correspond well with recent pCO(2) data from paleosol carbonate, suggesting a coupling of pCO(2) and temperature. To the extent that biodiversity is correlated with temperature, estimates of the severity of end-Cretaceous extinctions that are based on occurrence data from the warming peak are probably inflated, as we illustrate for North Dakota plants. However, our analysis of climate and facies considerations shows that the effects of bolide impact should be regarded as the most significant contributor to these plant extinctions.

@article{doi101073pnas0234701100,
    author = "Wilf, Peter and Johnson, Kirk R. and Huber, Brian T.",
    title = "Correlated terrestrial and marine evidence for global climate changes before mass extinction at the Cretaceous–Paleogene boundary",
    year = "2003",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Terrestrial climates near the time of the end-Cretaceous mass extinction are poorly known, limiting understanding of environmentally driven changes in biodiversity that occurred before bolide impact. We estimate paleotemperatures for the last approximately 1.1 million years of the Cretaceous (approximately 66.6-65.5 million years ago, Ma) by using fossil plants from North Dakota and employ paleomagnetic stratigraphy to correlate the results to foraminiferal paleoclimatic data from four middle- and high-latitude sites. Both plants and foraminifera indicate warming near 66.0 Ma, a warming peak from approximately 65.8 to 65.6 Ma, and cooling near 65.6 Ma, suggesting that these were global climate shifts. The warming peak coincides with the immigration of a thermophilic flora, maximum plant diversity, and the poleward range expansion of thermophilic foraminifera. Plant data indicate the continuation of relatively cool temperatures across the Cretaceous-Paleogene boundary; there is no indication of a major warming immediately after the boundary as previously reported. Our temperature proxies correspond well with recent pCO(2) data from paleosol carbonate, suggesting a coupling of pCO(2) and temperature. To the extent that biodiversity is correlated with temperature, estimates of the severity of end-Cretaceous extinctions that are based on occurrence data from the warming peak are probably inflated, as we illustrate for North Dakota plants. However, our analysis of climate and facies considerations shows that the effects of bolide impact should be regarded as the most significant contributor to these plant extinctions.",
    url = "https://doi.org/10.1073/pnas.0234701100",
    doi = "10.1073/pnas.0234701100",
    openalex = "W1987302968",
    references = "doi101038324148a0, doi101126science1064706, doi1011300091761319980260995adswat23co2"
}

Since the early l990s the Chicxulub crater on Yucatan, Mexico, has been hailed as the smoking gun that proves the hypothesis that an asteroid killed the dinosaurs and caused the mass extinction of many other organisms at the Cretaceous-Tertiary (K-T) boundary 65 million years ago. Here, we report evidence from a previously uninvestigated core, Yaxcopoil-1, drilled within the Chicxulub crater, indicating that this impact predated the K-T boundary by approximately 300,000 years and thus did not cause the end-Cretaceous mass extinction as commonly believed. The evidence supporting a pre-K-T age was obtained from Yaxcopoil-1 based on five independent proxies, each with characteristic signals across the K-T transition: sedimentology, biostratigraphy, magnetostratigraphy, stable isotopes, and iridium. These data are consistent with earlier evidence for a late Maastrichtian age of the microtektite deposits in northeastern Mexico.

@article{doi101073pnas0400396101,
    author = "Keller, Gerta and Adatte, Thierry and Stinnesbeck, Wolfgang and Rebolledo‐Vieyra, M. and Fucugauchi, Jaime Urrutia and Kramar, U. and Stüben, Doris",
    title = "Chicxulub impact predates the K-T boundary mass extinction",
    year = "2004",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Since the early l990s the Chicxulub crater on Yucatan, Mexico, has been hailed as the smoking gun that proves the hypothesis that an asteroid killed the dinosaurs and caused the mass extinction of many other organisms at the Cretaceous-Tertiary (K-T) boundary 65 million years ago. Here, we report evidence from a previously uninvestigated core, Yaxcopoil-1, drilled within the Chicxulub crater, indicating that this impact predated the K-T boundary by approximately 300,000 years and thus did not cause the end-Cretaceous mass extinction as commonly believed. The evidence supporting a pre-K-T age was obtained from Yaxcopoil-1 based on five independent proxies, each with characteristic signals across the K-T transition: sedimentology, biostratigraphy, magnetostratigraphy, stable isotopes, and iridium. These data are consistent with earlier evidence for a late Maastrichtian age of the microtektite deposits in northeastern Mexico.",
    url = "https://doi.org/10.1073/pnas.0400396101",
    doi = "10.1073/pnas.0400396101",
    openalex = "W1710439440",
    references = "alvarez1980extraterrestrial, doi1010079783642859168, doi101016s0012821x0000159x, doi101038359819a0, doi101126science2575072954, doi1011300091761319910190867ccapct23co2, doi1011300091761319920200099tbdwcu23co2, doi1011300091761319950230873ynssia23co2, doi1011300091761319980260995adswat23co2, doi101144gsjgs15420265"
}

High-resolution carbon isotope measurements of multiple stratigraphic sections in south China demonstrate that the pronounced carbon isotopic excursion at the Permian-Triassic boundary was not an isolated event but the first in a series of large fluctuations that continued throughout the Early Triassic before ending abruptly early in the Middle Triassic. The unusual behavior of the carbon cycle coincides with the delayed recovery from end-Permian extinction recorded by fossils, suggesting a direct relationship between Earth system function and biological rediversification in the aftermath of Earth's most devastating mass extinction.

@article{doi101126science1097023,
    author = "Payne, Jonathan L. and Lehrmann, Daniel J. and Wei, Jiayong and Orchard, Michael J. and Schrag, Daniel P. and Knoll, Andrew H.",
    title = "Large Perturbations of the Carbon Cycle During Recovery from the End-Permian Extinction",
    year = "2004",
    journal = "Science",
    abstract = "High-resolution carbon isotope measurements of multiple stratigraphic sections in south China demonstrate that the pronounced carbon isotopic excursion at the Permian-Triassic boundary was not an isolated event but the first in a series of large fluctuations that continued throughout the Early Triassic before ending abruptly early in the Middle Triassic. The unusual behavior of the carbon cycle coincides with the delayed recovery from end-Permian extinction recorded by fossils, suggesting a direct relationship between Earth system function and biological rediversification in the aftermath of Earth's most devastating mass extinction.",
    url = "https://doi.org/10.1126/science.1097023",
    doi = "10.1126/science.1097023",
    openalex = "W2130869324",
    references = "doi101016003101829400093n, doi101016s0012821x03003479, doi101016s0012825202001046, doi101017s0016756800007603, doi10102995pa02087, doi101073pnas032095199, doi101126science2064415217, doi101126science2735274452, doi101126science28053661039, doi101126science2895478432, doi1011300016760619961080195gcgbpt23co2"
}

The age and timing of the Permian-Triassic mass extinction have been difficult to determine because zircon populations from the type sections are typically affected by pervasive lead loss and contamination by indistinguishable older xenocrysts. Zircons from nine ash beds within the Shangsi and Meishan sections (China), pretreated by annealing followed by partial attack with hydrofluoric acid, result in suites of consistent and concordant uranium/lead (U/Pb) ages, eliminating the effects of lead loss. The U/Pb age of the main pulse of the extinction is 252.6 +/- 0.2 million years, synchronous with the Siberian flood volcanism, and it occurred within the quoted uncertainty.

@article{doi101126science1101012,
    author = "Mundil, Roland and Ludwig, K. R. and Metcalfe, Ian and Renne, Paul R.",
    title = "Age and Timing of the Permian Mass Extinctions: U/Pb Dating of Closed-System Zircons",
    year = "2004",
    journal = "Science",
    abstract = "The age and timing of the Permian-Triassic mass extinction have been difficult to determine because zircon populations from the type sections are typically affected by pervasive lead loss and contamination by indistinguishable older xenocrysts. Zircons from nine ash beds within the Shangsi and Meishan sections (China), pretreated by annealing followed by partial attack with hydrofluoric acid, result in suites of consistent and concordant uranium/lead (U/Pb) ages, eliminating the effects of lead loss. The U/Pb age of the main pulse of the extinction is 252.6 +/- 0.2 million years, synchronous with the Siberian flood volcanism, and it occurred within the quoted uncertainty.",
    url = "https://doi.org/10.1126/science.1101012",
    doi = "10.1126/science.1101012",
    openalex = "W1995573456",
    references = "doi101016001670378290165x, doi101016s0009254100002333, doi101016s0012821x01006082, doi101016s0016703798000593, doi101016s0016703799002045, doi101016s1631071303000063, doi10103836554, doi101126science28053661039, doi101126science2895478432, doi1018814epiiugs2001v24i2004"
}

@article{doi101016jpalaeo200505019,
    author = "Twitchett, Richard J.",
    title = "The palaeoclimatology, palaeoecology and palaeoenvironmental analysis of mass extinction events",
    year = "2005",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2005.05.019",
    doi = "10.1016/j.palaeo.2005.05.019",
    openalex = "W2099674340",
    references = "alvarez1980extraterrestrial, doi101016003101829400093n, doi1010160031018295000178, doi101016s0012825200000374, doi101016s0012825297834848, doi101016s003101820100476x, doi101016s0277379199000608, doi101016s0377839803000215, doi101073pnas0400396101, doi101073pnas813801, doi101093oso97801985491780010001, doi101126science1097023, doi101126science1104323, doi101126science2164542173, doi101126science27252651155, doi1011300091761319910190867ccapct23co2, doi1023073515466, openalexw658437845"
}

Abstract Mass extinctions are important to macroevolution not only because they involve a sharp increase in extinction intensity over “background” levels, but also because they bring a change in extinction selectivity, and these quantitative and qualitative shifts set the stage for evolutionary recoveries. The set of extinction intensities for all stratigraphic stages appears to fall into a single right-skewed distribution, but this apparent continuity may derive from failure to factor out the well-known secular trend in background extinction: high early Paleozoic rates fill in the gap between later background extinction and the major mass extinctions. In any case, the failure of many organism-, species-, and clade-level traits to predict survivorship during mass extinctions is a more important challenge to the extrapolationist premise that all macroevolutionary processes are simply smooth extensions of microevolution. Although a variety of factors have been found to correlate with taxon survivorship for particular extinction events, the most pervasive effect involves geographic range at the clade level, an emergent property independent of the range sizes of constituent species. Such differential extinction would impose “nonconstructive selectivity,” in which survivorship is unrelated to many organismic traits but is not strictly random. It also implies that correlations among taxon attributes may obscure causation, and even the focal level of selection, in the survival of a trait or clade, for example when widespread taxa within a major group tend to have particular body sizes, trophic habits, or metabolic rates. Survivorship patterns will also be sensitive to the inexact correlations of taxonomic, morphological, and functional diversity, to phylogenetically nonrandom extinction, and to the topology of evolutionary trees. Evolutionary recoveries may be as important as the extinction events themselves in shaping the long-term trajectories of individual clades and permitting once-marginal groups to diversify, but we know little about sorting processes during recovery intervals. However, both empirical extrapolationism (where outcomes can be predicted from observation of pre- or post-extinction patterns) and theoretical extrapolationism (where mechanisms reside exclusively at the level of organisms within populations) evidently fail during mass extinctions and their evolutionary aftermath. This does not mean that conventional natural selection was inoperative during mass extinctions, but that many features that promoted survivorship during background times were superseded as predictive factors by higher-level attributes. Many intriguing issues remain, including the generality of survivorship rules across extinction events; the potential for gradational changes in selectivity patterns with extinction intensity or the volatility of target clades; the heritability of clade-level traits; the macroevolutionary consequences of the inexact correlations between taxonomic, morphological, and functional diversity; the factors governing the dynamics and outcome of recoveries; and the spatial fabric of extinctions and recoveries. The detection of general survivorship rules—including the disappearance of many patterns evident during background times—demonstrates that studies of mass extinctions and recovery can contribute substantially to evolutionary theory.

@article{doi1016660094837320050310192meam20co2,
    author = "Jablonski, David",
    title = "Mass extinctions and macroevolution",
    year = "2005",
    journal = "Paleobiology",
    abstract = "Abstract Mass extinctions are important to macroevolution not only because they involve a sharp increase in extinction intensity over “background” levels, but also because they bring a change in extinction selectivity, and these quantitative and qualitative shifts set the stage for evolutionary recoveries. The set of extinction intensities for all stratigraphic stages appears to fall into a single right-skewed distribution, but this apparent continuity may derive from failure to factor out the well-known secular trend in background extinction: high early Paleozoic rates fill in the gap between later background extinction and the major mass extinctions. In any case, the failure of many organism-, species-, and clade-level traits to predict survivorship during mass extinctions is a more important challenge to the extrapolationist premise that all macroevolutionary processes are simply smooth extensions of microevolution. Although a variety of factors have been found to correlate with taxon survivorship for particular extinction events, the most pervasive effect involves geographic range at the clade level, an emergent property independent of the range sizes of constituent species. Such differential extinction would impose “nonconstructive selectivity,” in which survivorship is unrelated to many organismic traits but is not strictly random. It also implies that correlations among taxon attributes may obscure causation, and even the focal level of selection, in the survival of a trait or clade, for example when widespread taxa within a major group tend to have particular body sizes, trophic habits, or metabolic rates. Survivorship patterns will also be sensitive to the inexact correlations of taxonomic, morphological, and functional diversity, to phylogenetically nonrandom extinction, and to the topology of evolutionary trees. Evolutionary recoveries may be as important as the extinction events themselves in shaping the long-term trajectories of individual clades and permitting once-marginal groups to diversify, but we know little about sorting processes during recovery intervals. However, both empirical extrapolationism (where outcomes can be predicted from observation of pre- or post-extinction patterns) and theoretical extrapolationism (where mechanisms reside exclusively at the level of organisms within populations) evidently fail during mass extinctions and their evolutionary aftermath. This does not mean that conventional natural selection was inoperative during mass extinctions, but that many features that promoted survivorship during background times were superseded as predictive factors by higher-level attributes. Many intriguing issues remain, including the generality of survivorship rules across extinction events; the potential for gradational changes in selectivity patterns with extinction intensity or the volatility of target clades; the heritability of clade-level traits; the macroevolutionary consequences of the inexact correlations between taxonomic, morphological, and functional diversity; the factors governing the dynamics and outcome of recoveries; and the spatial fabric of extinctions and recoveries. The detection of general survivorship rules—including the disappearance of many patterns evident during background times—demonstrates that studies of mass extinctions and recovery can contribute substantially to evolutionary theory.",
    url = "https://doi.org/10.1666/0094-8373(2005)031[0192:meam]2.0.co;2",
    doi = "10.1666/0094-8373(2005)031[0192:meam]2.0.co;2",
    openalex = "W2178500685",
    references = "doi1010029780470999592, doi1010160031018281900924, doi101016s0012825202001046, doi101016s0031018299000887, doi101017s0094837300008186, doi101017s0094837300011350, doi101017s0094837300011787, doi101017s0094837300013178, doi101017s0094837300015864, doi101093oso97801985264070010001, doi101093plankt212343, doi101111j150239311986tb01898x, doi101126science1103960, doi101126science11536722, doi101126science21545391501, doi101126science2825387276, doi101144gsjgs15420265, doi101146annurevecolsys281495, doi101146annurevecolsys33030602152151, doi101666009483731999251mditer20co2, doi1016660094837320000260056cefisg20co2, doi1016660094837320050310006poaeit20co2, doi1023072409086, doi1023073514632, doi1023073515466, doi105860choice396411, hotton2002palynology, kitchell1986biological, openalexw2145250129, openalexw2764433274, rickards2002lazarus"
}

@article{doi101016jepsl200702018,
    author = "Knoll, Andrew H. and Bambach, Richard K. and Payne, Jonathan L. and Pruss, Sara B. and Fischer, Woodward W.",
    title = "Paleophysiology and end-Permian mass extinction",
    year = "2007",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/j.epsl.2007.02.018",
    doi = "10.1016/j.epsl.2007.02.018",
    openalex = "W2105387568",
    references = "doi1010160031018292901825, doi101016jpalaeo200611038, doi101016s0012825200000374, doi101016s1631071303000063, doi101073pnas092150999, doi101093oso97801985771880010001, doi101111j150239311993tb01799x, doi101126science1097023, doi101126science1101012, doi101126science2164542173, doi101146annurevecolsys35021103105715, doi1016660094837320040300522oeamdo20co2, doi105860choice435903"
}

@article{doi101016jpalaeo200702037,
    author = "Kring, D. A.",
    title = "The Chicxulub impact event and its environmental consequences at the Cretaceous–Tertiary boundary",
    year = "2007",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2007.02.037",
    doi = "10.1016/j.palaeo.2007.02.037",
    openalex = "W2059315150",
    references = "alvarez1980extraterrestrial, alvarez1990iridium, crossref1982geological, doi10102996rg03038, doi101038285198a0, doi101038338057a0, doi101038359819a0, doi101073pnas0400396101, doi101126science11538083, doi101126science21545391501, doi101126science25250131690, doi101126science2575072954, doi101126science2635144185, doi1011300091761319910190867ccapct23co2, doi1011300091761319920200099tbdwcu23co2, doi101130spe190p305, doi101130spe190p329, doi101130spe247, doi101130spe307, doi101146annurevearth27175"
}

The mitochondrial genomes of the dwarf crocodile, Osteolaemus tetraspis, and two species of dwarf caimans, the smooth-fronted caiman, Paleosuchus trigonatus, and Cuvier's dwarf caiman, Paleosuchus palpebrosus, were sequenced and included in a mitogenomic phylogenetic study. The phylogenetic analyses, which included a total of ten crocodylian species, yielded strong support to a basal split between Crocodylidae and Alligatoridae. Osteolaemus fell within the Crocodylidae as the sister group to Crocodylus. Gavialis and Tomistoma, which joined on a common branch, constituted a sister group to Crocodylus/Osteolaemus. This suggests that extant crocodylians are organized in two families: Alligatoridae and Crocodylidae. Within the Alligatoridae there was a basal split between Alligator and a branch that contained Paleosuchus and Caiman. The analyses also provided molecular estimates of various divergences applying recently established crocodylian and outgroup fossil calibration points. Molecular estimates based on amino acid data placed the divergence between Crocodylidae and Alligatoridae at 97-103 million years ago and that between Alligator and Caiman/Paleosuchus at 65-72 million years ago. Other crocodilian divergences were placed after the Cretaceous-Tertiary boundary. Thus, according to the molecular estimates, three extant crocodylian lineages have their roots in the Cretaceous. Considering the crocodylian diversification in the Cretaceous the molecular datings suggest that the extinction of the dinosaurs was also to some extent paralleled in the crocodylian evolution. However, for whatever reason, some crocodylian lineages survived into the Tertiary.

@article{doi101016jympev200706018,
    author = "Roos, Jonas and Aggarwal, Ramesh K and Janke, Axel",
    title = "Extended mitogenomic phylogenetic analyses yield new insight into crocodylian evolution and their survival of the Cretaceous-Tertiary boundary.",
    year = "2007",
    journal = "Molecular phylogenetics and evolution",
    abstract = "The mitochondrial genomes of the dwarf crocodile, Osteolaemus tetraspis, and two species of dwarf caimans, the smooth-fronted caiman, Paleosuchus trigonatus, and Cuvier's dwarf caiman, Paleosuchus palpebrosus, were sequenced and included in a mitogenomic phylogenetic study. The phylogenetic analyses, which included a total of ten crocodylian species, yielded strong support to a basal split between Crocodylidae and Alligatoridae. Osteolaemus fell within the Crocodylidae as the sister group to Crocodylus. Gavialis and Tomistoma, which joined on a common branch, constituted a sister group to Crocodylus/Osteolaemus. This suggests that extant crocodylians are organized in two families: Alligatoridae and Crocodylidae. Within the Alligatoridae there was a basal split between Alligator and a branch that contained Paleosuchus and Caiman. The analyses also provided molecular estimates of various divergences applying recently established crocodylian and outgroup fossil calibration points. Molecular estimates based on amino acid data placed the divergence between Crocodylidae and Alligatoridae at 97-103 million years ago and that between Alligator and Caiman/Paleosuchus at 65-72 million years ago. Other crocodilian divergences were placed after the Cretaceous-Tertiary boundary. Thus, according to the molecular estimates, three extant crocodylian lineages have their roots in the Cretaceous. Considering the crocodylian diversification in the Cretaceous the molecular datings suggest that the extinction of the dinosaurs was also to some extent paralleled in the crocodylian evolution. However, for whatever reason, some crocodylian lineages survived into the Tertiary.",
    url = "https://pubmed.ncbi.nlm.nih.gov/17719245/",
    doi = "10.1016/j.ympev.2007.06.018",
    openalex = "W2030337053",
    pmid = "17719245",
    references = "doi101007bf00160154, doi101007bf02101990, doi101016s0074769608620665, doi101093bioinformatics149817, doi101093bioinformatics183502, doi101093oxfordjournalsmolbeva003974, doi101093oxfordjournalsmolbeva026201, doi101093oxfordjournalsmolbeva040023, doi10118614712148418, openalexw3217097258"
}

A latest Cretaceous (68 to 65 million years ago) vertebrate microfossil assemblage discovered at Kakanaut in northeastern Russia reveals that dinosaurs were still highly diversified in Arctic regions just before the Cretaceous-Tertiary mass extinction event. Dinosaur eggshell fragments, belonging to hadrosaurids and non-avian theropods, indicate that at least several latest Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes. Palaeobotanical data suggest that these polar dinosaurs lived in a temperate climate (mean annual temperature about 10 degrees C), but the climate was apparently too cold for amphibians and ectothermic reptiles. The high diversity of Late Maastrichtian dinosaurs in high latitudes, where ectotherms are absent, strongly questions hypotheses according to which dinosaur extinction was a result of temperature decline, caused or not by the Chicxulub impact.

@article{doi101007s0011400804990,
    author = "Godefroit, Pascal and Golovneva, Lina and Shchepetov, Sergei and Garcia, Géraldine and Alekseev, Pavel",
    title = "The last polar dinosaurs: high diversity of latest Cretaceous arctic dinosaurs in Russia.",
    year = "2009",
    journal = "Die Naturwissenschaften",
    abstract = "A latest Cretaceous (68 to 65 million years ago) vertebrate microfossil assemblage discovered at Kakanaut in northeastern Russia reveals that dinosaurs were still highly diversified in Arctic regions just before the Cretaceous-Tertiary mass extinction event. Dinosaur eggshell fragments, belonging to hadrosaurids and non-avian theropods, indicate that at least several latest Cretaceous dinosaur taxa could reproduce in polar region and were probably year-round residents of high latitudes. Palaeobotanical data suggest that these polar dinosaurs lived in a temperate climate (mean annual temperature about 10 degrees C), but the climate was apparently too cold for amphibians and ectothermic reptiles. The high diversity of Late Maastrichtian dinosaurs in high latitudes, where ectotherms are absent, strongly questions hypotheses according to which dinosaur extinction was a result of temperature decline, caused or not by the Chicxulub impact.",
    url = "https://pubmed.ncbi.nlm.nih.gov/19089398/",
    doi = "10.1007/s00114-008-0499-0",
    openalex = "W2158462195",
    pmid = "19089398",
    references = "doi101017cbo9780511608377011, doi101038326143a0, doi10108002724634199510011271, doi101126science28253972241, doi1016710272463420020220564eaeftc20co2, doi105860choice331556, doi105860choice435902, doi105962p313819, openalexw1671792548, sloan1986gradual"
}

@article{doi101016jpalaeo200909018,
    author = "Riera, V. and Oms, Oriol and Gaete, Rodrigo and Galobart, Àngel",
    title = "The end-Cretaceous dinosaur succession in Europe: The Tremp Basin record (Spain)",
    year = "2009",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2009.09.018",
    doi = "10.1016/j.palaeo.2009.09.018",
    openalex = "W2117629247",
    references = "doi101006cres20000236, doi101007s0011400804990, doi101016jpalaeo200412005, doi101016jpalaeo200702039, doi101016s0195667105800229, doi101017s0016756800012413, doi10103824370, doi101111j1525139x201000805x, doi1011301052517320050154teotdi20co2, doi101666060231, doi10167102724634200323156ansosd20co2, leloeuff1994the, openalexw2246303955, openalexw51761775, openalexw762617646, russell2002synopsis"
}

The present paper completes a restudy of the main lava pile in the Deccan flood basalt province (trap) of India. Chenet et al. (2008) reported results from the upper third, and this paper reports the lower two thirds of the 3500‐m‐thick composite section. The methods employed are the same, i.e., combined use of petrology, volcanology, chemostratigraphy, morphology, K‐Ar absolute dating, study of sedimentary alteration horizons, and as the main correlation tool, analysis of detailed paleomagnetic remanence directions. The thickness and volume of the flood basalt province studied in this way are therefore tripled. A total of 169 sites from eight new sections are reported in this paper. Together with the results of Chenet et al. (2008), these data represent in total 70% of the 3500‐m combined section of the main Deccan traps province. This lava pile was erupted in some 30 major eruptive periods or single eruptive events (SEE), each with volumes ranging from 1000 to 20,000 km 3 and 41 individual lava units with a typical volume of 1300 km 3. Paleomagnetic analysis shows that some SEEs with thicknesses attaining 200 m were emplaced over distances in excess of 100 km (both likely underestimates, due to outcrop conditions) and up to 800 km. The total time of emission of all combined SEEs could have been (much) less than 10 ka, with most of the time recorded in a very small number of intervening alteration levels marking periods of volcanic quiescence (so‐called “big red boles”). The number of boles, thickness of the pulses, and morphology of the traps suggest that eruptive fluxes and volumes were larger in the older formations and slowed down with more and longer quiescence periods in the end. On the basis of geochronologic results published by Chenet et al. (2007) and paleontological results from Keller et al. (2008), we propose that volcanism occurred in three rather short, discrete phases or megapulses, an early one at ∼67.5 ± 1 Ma near the C30r/C30n transition and the two largest around 65 ± 1 Ma, one entirely within C29r just before the K‐T boundary, the other shortly afterward spanning the C29r/C29n reversal. We next estimate sulfur dioxide (likely a major agent of environmental stress) amounts and fluxes released by SEEs: they would have ranged from 5 to 100 Gt and 0.1 to 1 Gt/a, respectively, over durations possibly as short as 100 years for each SEE. The chemical input of the Chicxulub impact would have been on the same order as that of a very large single pulse. The impact, therefore, appears as important but incremental, neither the sole nor main cause of the Cretaceous‐Tertiary mass extinctions.

@article{doi1010292008jb005644,
    author = "Chenet, A. and Courtillot, Vincent and Fluteau, Frédéric and Gérard, Martine and Quidelleur, Xavier and Khadri, S. and Subbarao, Κ. V. and Thórdarson, T.",
    title = "Determination of rapid Deccan eruptions across the Cretaceous‐Tertiary boundary using paleomagnetic secular variation: 2. Constraints from analysis of eight new sections and synthesis for a 3500‐m‐thick composite section",
    year = "2009",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "The present paper completes a restudy of the main lava pile in the Deccan flood basalt province (trap) of India. Chenet et al. (2008) reported results from the upper third, and this paper reports the lower two thirds of the 3500‐m‐thick composite section. The methods employed are the same, i.e., combined use of petrology, volcanology, chemostratigraphy, morphology, K‐Ar absolute dating, study of sedimentary alteration horizons, and as the main correlation tool, analysis of detailed paleomagnetic remanence directions. The thickness and volume of the flood basalt province studied in this way are therefore tripled. A total of 169 sites from eight new sections are reported in this paper. Together with the results of Chenet et al. (2008), these data represent in total 70\% of the 3500‐m combined section of the main Deccan traps province. This lava pile was erupted in some 30 major eruptive periods or single eruptive events (SEE), each with volumes ranging from 1000 to 20,000 km 3 and 41 individual lava units with a typical volume of 1300 km 3. Paleomagnetic analysis shows that some SEEs with thicknesses attaining 200 m were emplaced over distances in excess of 100 km (both likely underestimates, due to outcrop conditions) and up to 800 km. The total time of emission of all combined SEEs could have been (much) less than 10 ka, with most of the time recorded in a very small number of intervening alteration levels marking periods of volcanic quiescence (so‐called “big red boles”). The number of boles, thickness of the pulses, and morphology of the traps suggest that eruptive fluxes and volumes were larger in the older formations and slowed down with more and longer quiescence periods in the end. On the basis of geochronologic results published by Chenet et al. (2007) and paleontological results from Keller et al. (2008), we propose that volcanism occurred in three rather short, discrete phases or megapulses, an early one at ∼67.5 ± 1 Ma near the C30r/C30n transition and the two largest around 65 ± 1 Ma, one entirely within C29r just before the K‐T boundary, the other shortly afterward spanning the C29r/C29n reversal. We next estimate sulfur dioxide (likely a major agent of environmental stress) amounts and fluxes released by SEEs: they would have ranged from 5 to 100 Gt and 0.1 to 1 Gt/a, respectively, over durations possibly as short as 100 years for each SEE. The chemical input of the Chicxulub impact would have been on the same order as that of a very large single pulse. The impact, therefore, appears as important but incremental, neither the sole nor main cause of the Cretaceous‐Tertiary mass extinctions.",
    url = "https://doi.org/10.1029/2008jb005644",
    doi = "10.1029/2008jb005644",
    openalex = "W2066351018",
    references = "doi1010160012821x86901184, doi101016jepsl200801015, doi101016s0012825200000374, doi101016s1631071303000063, doi1010292000jb000050, doi10102994jb03098, doi10108008120090500170393, doi101098rspa19530064, doi101111j1365246x1980tb02601x, openalexw1520428197, openalexw1575579655, openalexw2974218786"
}

Most flowering plants have been shown to be ancient polyploids that have undergone one or more whole genome duplications early in their evolution. Furthermore, many different plant lineages seem to have experienced an additional, more recent genome duplication. Starting from paralogous genes lying in duplicated segments or identified in large expressed sequence tag collections, we dated these youngest duplication events through penalized likelihood phylogenetic tree inference. We show that a majority of these independent genome duplications are clustered in time and seem to coincide with the Cretaceous-Tertiary (KT) boundary. The KT extinction event is the most recent mass extinction caused by one or more catastrophic events such as a massive asteroid impact and/or increased volcanic activity. These events are believed to have generated global wildfires and dust clouds that cut off sunlight during long periods of time resulting in the extinction of approximately 60% of plant species, as well as a majority of animals, including dinosaurs. Recent studies suggest that polyploid species can have a higher adaptability and increased tolerance to different environmental conditions. We propose that polyploidization may have contributed to the survival and propagation of several plant lineages during or following the KT extinction event. Due to advantages such as altered gene expression leading to hybrid vigor and an increased set of genes and alleles available for selection, polyploid plants might have been better able to adapt to the drastically changed environment 65 million years ago.

@article{doi101073pnas0900906106,
    author = "Fawcett, Jeffrey A. and Maere, Steven and de Peer, Yves Van",
    title = "Plants with double genomes might have had a better chance to survive the Cretaceous–Tertiary extinction event",
    year = "2009",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Most flowering plants have been shown to be ancient polyploids that have undergone one or more whole genome duplications early in their evolution. Furthermore, many different plant lineages seem to have experienced an additional, more recent genome duplication. Starting from paralogous genes lying in duplicated segments or identified in large expressed sequence tag collections, we dated these youngest duplication events through penalized likelihood phylogenetic tree inference. We show that a majority of these independent genome duplications are clustered in time and seem to coincide with the Cretaceous-Tertiary (KT) boundary. The KT extinction event is the most recent mass extinction caused by one or more catastrophic events such as a massive asteroid impact and/or increased volcanic activity. These events are believed to have generated global wildfires and dust clouds that cut off sunlight during long periods of time resulting in the extinction of approximately 60\% of plant species, as well as a majority of animals, including dinosaurs. Recent studies suggest that polyploid species can have a higher adaptability and increased tolerance to different environmental conditions. We propose that polyploidization may have contributed to the survival and propagation of several plant lineages during or following the KT extinction event. Due to advantages such as altered gene expression leading to hybrid vigor and an increased set of genes and alleles available for selection, polyploid plants might have been better able to adapt to the drastically changed environment 65 million years ago.",
    url = "https://doi.org/10.1073/pnas.0900906106",
    doi = "10.1073/pnas.0900906106",
    openalex = "W2152650625",
    references = "doi101038nature06148, doi101038nrg1711, doi101073pnas0400396101, doi10108010635150390235520, doi101093genetics15141531, doi101093molbevmsm088, doi101093nar22224673, doi101126science1128691, doi101126science29054941151, doi101146annurevgenet341401, doi101371journalpbio0040088"
}

The 260-million-year-old Emeishan volcanic province of southwest China overlies and is interbedded with Middle Permian carbonates that contain a record of the Guadalupian mass extinction. Sections in the region thus provide an opportunity to directly monitor the relative timing of extinction and volcanism within the same locations. These show that the onset of volcanism was marked by both large phreatomagmatic eruptions and extinctions amongst fusulinacean foraminifers and calcareous algae. The temporal coincidence of these two phenomena supports the idea of a cause-and-effect relationship. The crisis predates the onset of a major negative carbon isotope excursion that points to subsequent severe disturbance of the ocean-atmosphere carbon cycle.

@article{doi101126science1171956,
    author = "Wignall, Paul B. and Sun, Yadong and Bond, David P.G. and Izon, Gareth and Newton, Robert J. and Védrine, Stéphanie and Widdowson, Mike and Ali, Jason R. and Lai, Xulong and Jiang, Haishui and Cope, Helen A. and Bottrell, Simon H.",
    title = "Volcanism, Mass Extinction, and Carbon Isotope Fluctuations in the Middle Permian of China",
    year = "2009",
    journal = "Science",
    abstract = "The 260-million-year-old Emeishan volcanic province of southwest China overlies and is interbedded with Middle Permian carbonates that contain a record of the Guadalupian mass extinction. Sections in the region thus provide an opportunity to directly monitor the relative timing of extinction and volcanism within the same locations. These show that the onset of volcanism was marked by both large phreatomagmatic eruptions and extinctions amongst fusulinacean foraminifers and calcareous algae. The temporal coincidence of these two phenomena supports the idea of a cause-and-effect relationship. The crisis predates the onset of a major negative carbon isotope excursion that points to subsequent severe disturbance of the ocean-atmosphere carbon cycle.",
    url = "https://doi.org/10.1126/science.1171956",
    doi = "10.1126/science.1171956",
    openalex = "W1966990309",
    references = "doi101016jepsl200801015"
}

@article{doi101016jpalaeo201005036,
    author = "Kidder, David L. and Worsley, Thomas R.",
    title = "Phanerozoic Large Igneous Provinces (LIPs), HEATT (Haline Euxinic Acidic Thermal Transgression) episodes, and mass extinctions",
    year = "2010",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2010.05.036",
    doi = "10.1016/j.palaeo.2010.05.036",
    openalex = "W1992272796",
    references = "alvarez1980extraterrestrial, doi1010160009254180900479, doi101016jpalaeo200606026, doi101016jpalaeo200706013, doi101029jc086ic10p09776, doi101029pa005i001p00001, doi101038nature03906, doi101038nature06588, doi101073pnas0400396101, doi101126science1161648, doi101126science23547931156, doi1011300091761319980260995adswat23co2, doi101130g211551, openalexw2106559152, openalexw2912219260"
}

The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.

@article{doi101126science1177265,
    author = "Schulte, Peter and Alegret, Laia and Arenillas, Ignacio and Arz, José Antonio and Barton, P. J. and Bown, Paul R. and Bralower, Timothy J. and Christeson, Gail and Claeys, Philippe and Cockell, Charles S. and Collins, G. S. and Deutsch, A. and Goldin, Tamara and Goto, Kazuhisa and Grajales-Nishimura, José Manuel and Grieve, R. A. F. and Gulick, S. P. S. and Johnson, Kirk R. and Kiessling, Wolfgang and Koeberl, Christian and Kring, D. A. and MacLeod, Kenneth G. and Matsui, Takafumi and Melosh, J. and Montanari, Alessandro and Morgan, Joanna and Neal, C. R. and Nichols, Douglas J. and Norris, Richard D. and Pierazzo, E. and Ravizza, Greg and Rebolledo‐Vieyra, M. and Reimold, W. U. and Robin, Éric and Salge, T. and Speijer, Robert P. and Sweet, A R and Urrutia‐Fucugauchi, J. and Vajda, Vivi and Whalen, Michael T. and Willumsen, Pi Suhr",
    title = "The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary",
    year = "2010",
    journal = "Science",
    abstract = "The Cretaceous-Paleogene boundary approximately 65.5 million years ago marks one of the three largest mass extinctions in the past 500 million years. The extinction event coincided with a large asteroid impact at Chicxulub, Mexico, and occurred within the time of Deccan flood basalt volcanism in India. Here, we synthesize records of the global stratigraphy across this boundary to assess the proposed causes of the mass extinction. Notably, a single ejecta-rich deposit compositionally linked to the Chicxulub impact is globally distributed at the Cretaceous-Paleogene boundary. The temporal match between the ejecta layer and the onset of the extinctions and the agreement of ecological patterns in the fossil record with modeled environmental perturbations (for example, darkness and cooling) lead us to conclude that the Chicxulub impact triggered the mass extinction.",
    url = "https://doi.org/10.1126/science.1177265",
    doi = "10.1126/science.1177265",
    openalex = "W2160490562",
    references = "alvarez1980extraterrestrial, doi101016jepsl200605041, doi101016jepsl200607020, doi101016jepsl200902019, doi101016jpalaeo200702037, doi101016jpalaeo200709016, doi101017cbo9780511535536, doi1010292008jb005644, doi10102996rg03038, doi10102997je01743, doi101038285198a0, doi101073pnas0802597105, doi101126science1064706, doi101126science20844481095, doi1011300091761319910190867ccapct23co2, doi101130081372356655, doi1011302007242401, doi101146annurevearth27175, doi101146annurevecolsys35021103105715"
}

Abstract: The Pliensbachian–Toarcian interval was marked by major environmental disturbances and by a second-order mass extinction. Here, we reappraise the taxonomic, spatiotemporal and selective dynamics of extinctions over the whole interval, by analysing a high-resolution dataset of 772 ammonite species from NW Tethyan and Arctic domains. On average, 40–65% of ammonite species disappeared during each subchronozone, but higher extinction pulses (reaching 70–90%) prevailed from the Margaritatus to the Dispansum Chronozone. The main extinctions, corresponding to the Gibbosus, Pliensbachian–Toarcian boundary, Semicelatum, Bifrons–Variabilis, and Dispansum events, differed in their dynamics, suggesting episodes of ecological stress related to climate change, regression, disturbance in the carbon cycle or anoxia. The multi-pulsed volcanic activity in the Karoo–Ferrar province could well have triggered these ecological changes. In addition, ammonites experienced a morphological bottleneck during the Gibbosus event, 1 Ma before the Early Toarcian diversity collapse. Typically, drops in richness were related both to high extinctions and to declines in origination rates. This feature could result from strengthened ecological stresses related to the temporal overlap of environmental disturbances. After the Early Toarcian crisis, the recovery of ammonites was rapid (2 Ma) and probably influenced by a coeval marine transgression. Supplementary material: Figures showing a comparison of extinction and origination patterns based on different datasets, and variations of the morphospace occupation are available at http://www.geolsoc.org.uk/SUP18381.

@article{doi101144001676492009068,
    author = "Dera, Guillaume and Neige, Pascal and Dommergues, Jean‐Louis and Fara, Emmanuel and Laffont, Rémi and Pellenard, Pierre",
    title = "High-resolution dynamics of Early Jurassic marine extinctions: the case of Pliensbachian–Toarcian ammonites (Cephalopoda)",
    year = "2010",
    journal = "Journal of the Geological Society",
    abstract = "Abstract: The Pliensbachian–Toarcian interval was marked by major environmental disturbances and by a second-order mass extinction. Here, we reappraise the taxonomic, spatiotemporal and selective dynamics of extinctions over the whole interval, by analysing a high-resolution dataset of 772 ammonite species from NW Tethyan and Arctic domains. On average, 40–65\% of ammonite species disappeared during each subchronozone, but higher extinction pulses (reaching 70–90\%) prevailed from the Margaritatus to the Dispansum Chronozone. The main extinctions, corresponding to the Gibbosus, Pliensbachian–Toarcian boundary, Semicelatum, Bifrons–Variabilis, and Dispansum events, differed in their dynamics, suggesting episodes of ecological stress related to climate change, regression, disturbance in the carbon cycle or anoxia. The multi-pulsed volcanic activity in the Karoo–Ferrar province could well have triggered these ecological changes. In addition, ammonites experienced a morphological bottleneck during the Gibbosus event, 1 Ma before the Early Toarcian diversity collapse. Typically, drops in richness were related both to high extinctions and to declines in origination rates. This feature could result from strengthened ecological stresses related to the temporal overlap of environmental disturbances. After the Early Toarcian crisis, the recovery of ammonites was rapid (2 Ma) and probably influenced by a coeval marine transgression. Supplementary material: Figures showing a comparison of extinction and origination patterns based on different datasets, and variations of the morphospace occupation are available at http://www.geolsoc.org.uk/SUP18381.",
    url = "https://doi.org/10.1144/0016-76492009-068",
    doi = "10.1144/0016-76492009-068",
    openalex = "W2015676515",
    references = "doi101007978147579153216, doi101016jpalaeo200505019, doi101666070341, doi1034194geusbv14646"
}

@article{doi101016jcoviro201110013,
    author = "Wang, Lin‐Fa and Walker, Peter J. and Poon, Leo L. M.",
    title = "Mass extinctions, biodiversity and mitochondrial function: are bats ‘special’ as reservoirs for emerging viruses?",
    year = "2011",
    journal = "Current Opinion in Virology",
    url = "https://doi.org/10.1016/j.coviro.2011.10.013",
    doi = "10.1016/j.coviro.2011.10.013",
    openalex = "W1998871189",
    references = "doi101038359819a0, doi101126science15437541333"
}

@article{doi101016jepsl201012033,
    author = "Meyer, Katja and Yu, Meiyi and Jost, A. B. and Kelley, Brian M. and Payne, Jonathan L.",
    title = "δ13C evidence that high primary productivity delayed recovery from end-Permian mass extinction",
    year = "2011",
    journal = "Earth and Planetary Science Letters",
    url = "https://doi.org/10.1016/j.epsl.2010.12.033",
    doi = "10.1016/j.epsl.2010.12.033",
    openalex = "W2041211732",
    references = "doi101016jpalaeo200505019, doi1010292007pa001458"
}

@article{doi101038nature09678,
    author = "Barnosky, Anthony D. and Matzke, Nicholas J. and Tomiya, Susumu and Wogan, Guinevere O. U. and Swartz, Brian and Quental, Tiago B. and Marshall, Charles R. and McGuire, Jenny L. and Lindsey, Emily and Maguire, Kaitlin C. and Mersey, Ben and Ferrer, Elizabeth Anne",
    title = "Has the Earth’s sixth mass extinction already arrived?",
    year = "2011",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature09678",
    doi = "10.1038/nature09678",
    openalex = "W2002682820",
    references = "alvarez1980extraterrestrial, doi101016jcretres200805030, doi101016jtree200803011, doi101017s0094837300016134, doi101038367231a0, doi101038nature02121, doi101073pnas0801921105, doi101073pnas0805482105, doi101073pnas101092598, doi101098rstb19940045, doi101111j15231739200801044x, doi101126science1069349, doi101126science11537491, doi101126science1156963, doi101126science1177265, doi101126science1184695, doi101126science1194442, doi101126science1196624, doi101126science20844481095, doi101126science21545391501, doi101126science2695222347, doi101146annurevearth33092203122654, doi101666070341"
}

The effect of the Cretaceous-Paleogene (K-Pg) (formerly Cretaceous-Tertiary, K-T) mass extinction on avian evolution is debated, primarily because of the poor fossil record of Late Cretaceous birds. In particular, it remains unclear whether archaic birds became extinct gradually over the course of the Cretaceous or whether they remained diverse up to the end of the Cretaceous and perished in the K-Pg mass extinction. Here, we describe a diverse avifauna from the latest Maastrichtian of western North America, which provides definitive evidence for the persistence of a range of archaic birds to within 300,000 y of the K-Pg boundary. A total of 17 species are identified, including 7 species of archaic bird, representing Enantiornithes, Ichthyornithes, Hesperornithes, and an Apsaravis-like bird. None of these groups are known to survive into the Paleogene, and their persistence into the latest Maastrichtian therefore provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact. Most of the birds described here represent advanced ornithurines, showing that a major radiation of Ornithurae preceded the end of the Cretaceous, but none can be definitively referred to the Neornithes. This avifauna is the most diverse known from the Late Cretaceous, and although size disparity is lower than in modern birds, the assemblage includes both smaller forms and some of the largest volant birds known from the Mesozoic, emphasizing the degree to which avian diversification had proceeded by the end of the age of dinosaurs.

@article{doi101073pnas1110395108,
    author = "Longrich, Nicholas R. and Tokaryk, Tim T. and Field, Daniel J.",
    title = "Mass extinction of birds at the Cretaceous–Paleogene (K–Pg) boundary",
    year = "2011",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "The effect of the Cretaceous-Paleogene (K-Pg) (formerly Cretaceous-Tertiary, K-T) mass extinction on avian evolution is debated, primarily because of the poor fossil record of Late Cretaceous birds. In particular, it remains unclear whether archaic birds became extinct gradually over the course of the Cretaceous or whether they remained diverse up to the end of the Cretaceous and perished in the K-Pg mass extinction. Here, we describe a diverse avifauna from the latest Maastrichtian of western North America, which provides definitive evidence for the persistence of a range of archaic birds to within 300,000 y of the K-Pg boundary. A total of 17 species are identified, including 7 species of archaic bird, representing Enantiornithes, Ichthyornithes, Hesperornithes, and an Apsaravis-like bird. None of these groups are known to survive into the Paleogene, and their persistence into the latest Maastrichtian therefore provides strong evidence for a mass extinction of archaic birds coinciding with the Chicxulub asteroid impact. Most of the birds described here represent advanced ornithurines, showing that a major radiation of Ornithurae preceded the end of the Cretaceous, but none can be definitively referred to the Neornithes. This avifauna is the most diverse known from the Late Cretaceous, and although size disparity is lower than in modern birds, the assemblage includes both smaller forms and some of the largest volant birds known from the Mesozoic, emphasizing the degree to which avian diversification had proceeded by the end of the age of dinosaurs.",
    url = "https://doi.org/10.1073/pnas.1110395108",
    doi = "10.1073/pnas.1110395108",
    openalex = "W2083202587",
    references = "doi1010029780470750711, doi101038381226a0, doi101098rsbl20060523, doi101126science1177265, doi101126science27553031109, doi101126science27553031113, doi1012019781420064452, doi105860choice343307, openalexw1535663436, openalexw3217097258"
}

An asteroid impact at the end of the Cretaceous caused mass extinction, but extinction mechanisms are not well-understood. The collapse of sea surface to sea floor carbon isotope gradients has been interpreted as reflecting a global collapse of primary productivity (Strangelove Ocean) or export productivity (Living Ocean), which caused mass extinction higher in the marine food chain. Phytoplankton-dependent benthic foraminifera on the deep-sea floor, however, did not suffer significant extinction, suggesting that export productivity persisted at a level sufficient to support their populations. We compare benthic foraminiferal records with benthic and bulk stable carbon isotope records from the Pacific, Southeast Atlantic, and Southern Oceans. We conclude that end-Cretaceous decrease in export productivity was moderate, regional, and insufficient to explain marine mass extinction. A transient episode of surface ocean acidification may have been the main cause of extinction of calcifying plankton and ammonites, and recovery of productivity may have been as fast in the oceans as on land.

@article{doi101073pnas1110601109,
    author = "Alegret, Laia and Thomas, Ellen and Lohmann, Kyger C.",
    title = "End-Cretaceous marine mass extinction not caused by productivity collapse",
    year = "2011",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "An asteroid impact at the end of the Cretaceous caused mass extinction, but extinction mechanisms are not well-understood. The collapse of sea surface to sea floor carbon isotope gradients has been interpreted as reflecting a global collapse of primary productivity (Strangelove Ocean) or export productivity (Living Ocean), which caused mass extinction higher in the marine food chain. Phytoplankton-dependent benthic foraminifera on the deep-sea floor, however, did not suffer significant extinction, suggesting that export productivity persisted at a level sufficient to support their populations. We compare benthic foraminiferal records with benthic and bulk stable carbon isotope records from the Pacific, Southeast Atlantic, and Southern Oceans. We conclude that end-Cretaceous decrease in export productivity was moderate, regional, and insufficient to explain marine mass extinction. A transient episode of surface ocean acidification may have been the main cause of extinction of calcifying plankton and ammonites, and recovery of productivity may have been as fast in the oceans as on land.",
    url = "https://doi.org/10.1073/pnas.1110601109",
    doi = "10.1073/pnas.1110601109",
    openalex = "W2167653235",
    references = "doi101016jpalaeo200702037, doi101666110271"
}

Widespread development of microbialites characterizes the substrate and ecological response during the aftermath of two of the 'big five' mass extinctions of the Phanerozoic. This study reviews the microbial response recorded by macroscopic microbial structures to these events to examine how extinction mechanism may be linked to the style of microbialite development. Two main styles of response are recognized: (i) the expansion of microbialites into environments not previously occupied during the pre-extinction interval and (ii) increases in microbialite abundance and attainment of ecological dominance within environments occupied prior to the extinction. The Late Devonian biotic crisis contributed toward the decimation of platform margin reef taxa and was followed by increases in microbialite abundance in Famennian and earliest Carboniferous platform interior, margin, and slope settings. The end-Permian event records the suppression of infaunal activity and an elimination of metazoan-dominated reefs. The aftermath of this mass extinction is characterized by the expansion of microbialites into new environments including offshore and nearshore ramp, platform interior, and slope settings. The mass extinctions at the end of the Triassic and Cretaceous have not yet been associated with a macroscopic microbial response, although one has been suggested for the end-Ordovician event. The case for microbialites behaving as 'disaster forms' in the aftermath of mass extinctions accurately describes the response following the Late Devonian and end-Permian events, and this may be because each is marked by the reduction of reef communities in addition to a suppression of bioturbation related to the development of shallow-water anoxia.

@article{doi101111j14724669201100305x,
    author = "Mata, Scott A. and Bottjer, David J.",
    title = "Microbes and mass extinctions: paleoenvironmental distribution of microbialites during times of biotic crisis",
    year = "2011",
    journal = "Geobiology",
    abstract = "Widespread development of microbialites characterizes the substrate and ecological response during the aftermath of two of the 'big five' mass extinctions of the Phanerozoic. This study reviews the microbial response recorded by macroscopic microbial structures to these events to examine how extinction mechanism may be linked to the style of microbialite development. Two main styles of response are recognized: (i) the expansion of microbialites into environments not previously occupied during the pre-extinction interval and (ii) increases in microbialite abundance and attainment of ecological dominance within environments occupied prior to the extinction. The Late Devonian biotic crisis contributed toward the decimation of platform margin reef taxa and was followed by increases in microbialite abundance in Famennian and earliest Carboniferous platform interior, margin, and slope settings. The end-Permian event records the suppression of infaunal activity and an elimination of metazoan-dominated reefs. The aftermath of this mass extinction is characterized by the expansion of microbialites into new environments including offshore and nearshore ramp, platform interior, and slope settings. The mass extinctions at the end of the Triassic and Cretaceous have not yet been associated with a macroscopic microbial response, although one has been suggested for the end-Ordovician event. The case for microbialites behaving as 'disaster forms' in the aftermath of mass extinctions accurately describes the response following the Late Devonian and end-Permian events, and this may be because each is marked by the reduction of reef communities in addition to a suppression of bioturbation related to the development of shallow-water anoxia.",
    url = "https://doi.org/10.1111/j.1472-4669.2011.00305.x",
    doi = "10.1111/j.1472-4669.2011.00305.x",
    openalex = "W1836053577",
    references = "alvarez1980extraterrestrial, doi101002sici1099103419991112344321aidgj80930co2i, doi1010079783662087268, doi101016s0012825200000374, doi101073pnas0400396101, doi101093oso97801985491780010001, doi101126science1177265, doi101126science21445271341, doi101126science21545391501, doi101126science27252651155, doi101126science2845414616, doi10113000167606198596567defie20co2, doi101144gslmem19900120101"
}

Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.

@article{doi101126science1211028,
    author = "Meredith, Robert W. and Janečka, Jan E. and Gatesy, John and Ryder, Oliver A. and Fisher, Colleen A. and Teeling, Emma C. and Goodbla, Alisha and Eizirik, Eduardo and Simão, Taiz L. L. and Stadler, Tanja and Rabosky, Daniel L. and Honeycutt, Rodney L. and Flynn, John J. and Ingram, Colleen M. and Steiner, Cynthia and Williams, Tiffani L. and Robinson, Terence J. and Burk-Herrick, Angela and Westerman, Michael and Ayoub, Nadia A. and Springer, Mark S. and Murphy, William J.",
    title = "Impacts of the Cretaceous Terrestrial Revolution and KPg Extinction on Mammal Diversification",
    year = "2011",
    journal = "Science",
    abstract = "Previous analyses of relations, divergence times, and diversification patterns among extant mammalian families have relied on supertree methods and local molecular clocks. We constructed a molecular supermatrix for mammalian families and analyzed these data with likelihood-based methods and relaxed molecular clocks. Phylogenetic analyses resulted in a robust phylogeny with better resolution than phylogenies from supertree methods. Relaxed clock analyses support the long-fuse model of diversification and highlight the importance of including multiple fossil calibrations that are spread across the tree. Molecular time trees and diversification analyses suggest important roles for the Cretaceous Terrestrial Revolution and Cretaceous-Paleogene (KPg) mass extinction in opening up ecospace that promoted interordinal and intraordinal diversification, respectively. By contrast, diversification analyses provide no support for the hypothesis concerning the delayed rise of present-day mammals during the Eocene Period.",
    url = "https://doi.org/10.1126/science.1211028",
    doi = "10.1126/science.1211028",
    openalex = "W2140803428",
    references = "doi101016jtree200610002, doi101023a1011317930838, doi101038381226a0, doi101038nature05634, doi101038nature09705, doi101038nature10291, doi101073pnas0334222100, doi101073pnas1016876108, doi101093sysbiosyp031, doi101101gr5918807, doi101126science1067179, doi101353book59141"
}

Godefroit, Pascal, Bolotsky, Yuri L., Bolotsky, Ivan Y. (2012): Osteology and relationships of Olorotitan arharensis, a hollow-crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia. Acta Palaeontologica Polonica 57 (3): 527-560, DOI: 10.4202/app.2011.0051, URL: http://dx.doi.org/10.4202/app.2011.0051

@article{doi104202app20110051,
    author = "Godefroit, Pascal and Bolotsky, Yuri L. and Bolotsky, Ivan",
    title = "Osteology and Relationships of Olorotitan arharensis, A Hollow-Crested Hadrosaurid Dinosaur from the Latest Cretaceous of Far Eastern Russia",
    year = "2011",
    journal = "Acta Palaeontologica Polonica",
    abstract = "Godefroit, Pascal, Bolotsky, Yuri L., Bolotsky, Ivan Y. (2012): Osteology and relationships of Olorotitan arharensis, a hollow-crested hadrosaurid dinosaur from the latest Cretaceous of Far Eastern Russia. Acta Palaeontologica Polonica 57 (3): 527-560, DOI: 10.4202/app.2011.0051, URL: http://dx.doi.org/10.4202/app.2011.0051",
    url = "https://doi.org/10.4202/app.2011.0051",
    doi = "10.4202/app.2011.0051",
    openalex = "W2115543982",
    references = "doi101007s0011400804990, doi1010160031018291900605, doi101073pnas1006970107, doi101098rspl18870117, doi101111j10963642200900617x, doi101111j146979981985tb04915x, doi101126science11282807, doi101130spe40p1, doi1016710390290428, doi1016711110, doi102113gsrocky8specialpaper11, doi1023071005355, doi105962p313819, openalexw3206657856, openalexw3215057009"
}

@article{doi101038ncomms1815,
    author = "Brusatte, Stephen L. and Butler, Richard J. and Prieto‐Márquez, Albert and Norell, Mark A.",
    title = "Dinosaur morphological diversity and the end-Cretaceous extinction",
    year = "2012",
    journal = "Nature Communications",
    url = "https://doi.org/10.1038/ncomms1815",
    doi = "10.1038/ncomms1815",
    openalex = "W2099332157",
    references = "alvarez1980extraterrestrial, doi101007s0011400804990, doi101017s009483730001263x, doi101017s0094837300015864, doi101017s1477201907002246, doi101073pnas1006970107, doi101080027246342010483632, doi101098rspb20080715, doi101111j10963642200900617x, doi101126science1161833, doi101126science1177265, doi101525california97805202462320010001, doi1016660094837320010270583bitpar20co2, doi1016660094837320010270695dcimop20co2"
}

BACKGROUND: Body size is intimately related to the physiology and ecology of an organism. Therefore, accurate and consistent body mass estimates are essential for inferring numerous aspects of paleobiology in extinct taxa, and investigating large-scale evolutionary and ecological patterns in the history of life. Scaling relationships between skeletal measurements and body mass in birds and mammals are commonly used to predict body mass in extinct members of these crown clades, but the applicability of these models for predicting mass in more distantly related stem taxa, such as non-avian dinosaurs and non-mammalian synapsids, has been criticized on biomechanical grounds. Here we test the major criticisms of scaling methods for estimating body mass using an extensive dataset of mammalian and non-avian reptilian species derived from individual skeletons with live weights. RESULTS: Significant differences in the limb scaling of mammals and reptiles are noted in comparisons of limb proportions and limb length to body mass. Remarkably, however, the relationship between proximal (stylopodial) limb bone circumference and body mass is highly conserved in extant terrestrial mammals and reptiles, in spite of their disparate limb postures, gaits, and phylogenetic histories. As a result, we are able to conclusively reject the main criticisms of scaling methods that question the applicability of a universal scaling equation for estimating body mass in distantly related taxa. CONCLUSIONS: The conserved nature of the relationship between stylopodial circumference and body mass suggests that the minimum diaphyseal circumference of the major weight-bearing bones is only weakly influenced by the varied forces exerted on the limbs (that is, compression or torsion) and most strongly related to the mass of the animal. Our results, therefore, provide a much-needed, robust, phylogenetically corrected framework for accurate and consistent estimation of body mass in extinct terrestrial quadrupeds, which is important for a wide range of paleobiological studies (including growth rates, metabolism, and energetics) and meta-analyses of body size evolution.

@article{doi101186174170071060,
    author = "Campione, Nicolás E. and Evans, David C.",
    title = "A universal scaling relationship between body mass and proximal limb bone dimensions in quadrupedal terrestrial tetrapods",
    year = "2012",
    journal = "BMC Biology",
    abstract = "BACKGROUND: Body size is intimately related to the physiology and ecology of an organism. Therefore, accurate and consistent body mass estimates are essential for inferring numerous aspects of paleobiology in extinct taxa, and investigating large-scale evolutionary and ecological patterns in the history of life. Scaling relationships between skeletal measurements and body mass in birds and mammals are commonly used to predict body mass in extinct members of these crown clades, but the applicability of these models for predicting mass in more distantly related stem taxa, such as non-avian dinosaurs and non-mammalian synapsids, has been criticized on biomechanical grounds. Here we test the major criticisms of scaling methods for estimating body mass using an extensive dataset of mammalian and non-avian reptilian species derived from individual skeletons with live weights. RESULTS: Significant differences in the limb scaling of mammals and reptiles are noted in comparisons of limb proportions and limb length to body mass. Remarkably, however, the relationship between proximal (stylopodial) limb bone circumference and body mass is highly conserved in extant terrestrial mammals and reptiles, in spite of their disparate limb postures, gaits, and phylogenetic histories. As a result, we are able to conclusively reject the main criticisms of scaling methods that question the applicability of a universal scaling equation for estimating body mass in distantly related taxa. CONCLUSIONS: The conserved nature of the relationship between stylopodial circumference and body mass suggests that the minimum diaphyseal circumference of the major weight-bearing bones is only weakly influenced by the varied forces exerted on the limbs (that is, compression or torsion) and most strongly related to the mass of the animal. Our results, therefore, provide a much-needed, robust, phylogenetically corrected framework for accurate and consistent estimation of body mass in extinct terrestrial quadrupeds, which is important for a wide range of paleobiological studies (including growth rates, metabolism, and energetics) and meta-analyses of body size evolution.",
    url = "https://doi.org/10.1186/1741-7007-10-60",
    doi = "10.1186/1741-7007-10-60",
    openalex = "W2053913541",
    references = "christiansen2004mass, doi101016jympev200706018, doi101017cbo9780511608551, doi101017s1464793106007007, doi101086284325, doi101093bioinformaticsbtg412, doi101093sysbio41118, doi101111j146979981985tb04915x, doi101111j251761611995tb02031x, doi101126science1061967, doi101159000452856, doi103998mpub9690664, doi105860choice290302, doi105860choice490282, openalexw1558456135, openalexw2611511275"
}

PREFACE: James O. Farlow and M. K. Brett-Surman PART ONE: THE DISCOVERY OF DINOSAURS The Earliest Discoveries: William A. S. Sarjeant European Dinosaur Hunters: Hans-Dieter Sues North American Dinosaur Hunters: Edwin H. Colbert Asian Dinosaur Hunters: John R. Lavas Dinosaur Hunters of the Southern Continents: Thomas R. Holtz, Jr. PART TWO: THE STUDY OF DINOSAURS Hunting for Dinosaur Bones: David D. Gillette The Osteology of the Dinosaurs: Thomas R. Holtz, Jr. and M. K.Brett-Surman The Taxonomy and Systematics of the Dinosaurs: Thomas R. Holtz, Jr. and M. K. Brett-Surman Dinosaurs and Geologic Time: James O. Farlow The Scientific Study of Dinosaurs: Ralph E. Chapman Molecular Paleontology: Rationale and Techniques for the Study of Ancient Biomolecules: Mary Higby Schweitzer Dinosaurs as Museum Exhibits: Kenneth Carpenter Restoring Dinosaurs as Living Animals: Douglas Henderson PART THREE: THE GROUPS OF DINOSAURS Introduction: James O. Farlow and M. K. Brett-Surman Politics and Paleontology: Richard Owen and the Invention of Dinosaurs: Hugh Torrens Evolution of the Archosaurs: J. Michael Parrish Origin and Early Evolution of Dinosaurs: Michael J. Benton Theropods: Philip J. Currie Segnosaurs (Therezinosaurs): Teresa Maryanska Prosauropods: Jacques VanHeerden Sauropods: John S. McIntosh, M. K. Brett-Surman, and James O. Farlow Stegosaurs: Peter M. Galton Ankylosaurs: Kenneth Carpenter Marginocephalians: Catherine A. Forster and Paul C. Sereno Ornithopods: M. K. Brett-Surman PART FOUR: BIOLOGY OF THE DINOSAURS Land Plants as Food and Habitat in the Age of Dinosaurs: Bruce H. Tiffney What Did Dinosaurs Eat? Coprolites and Other Direct Evidence of Dinosaur Diets: Karen Chin Dinosaur Combat and Courtship: Scott Sampson Dinosaur Eggs: Karl F. Hirsch and Darla K. Zelenitsky How Dinosaurs Grew: R. E. H. Reid Engineering a Dinosaur: R. McN. Alexander Dinosaurian Paleopathology: Bruce M. Rothschild Dinosaurian Physiology: the Case for Intermediate Dinosaurs: R. E. H. Reid Oxygen Isotopes in Dinosaur Bone: Reese E. Barrick, Michael K. Stoskopf, and William J. Showers A Blueprint for Giants: Do Living Reptiles, Birds or Mammals Provide the Best Model for the Physiology of Large Dinosaurs? Frank V. Paladino, James R. Spotila, and Peter Dodson New Insights into the Metabolic Physiology of Dinosaurs: John Ruben, Andrew Leitch, Willem Hillenius, Nicholas Geist, and Terry Jones The Scientific Study of Dinosaur Footprints: James O. Farlow and Ralph E. Chapman The Paleoecological and Paleoenvironmental Utility of Dinosaur Tracks: Martin G. Lockley PART FIVE: DINOSAUR EVOLUTION IN THE CHANGING WORLD OF THE MESOZOIC ERA Biogeography for Dinosaurs: Ralph E. Molnar Major Groups of Non-Dinosaurian Vertebrates of the Mesozoic Era: Michael Morales Continental Tetrapods of the Early Mesozoic: Faunas and Faunal Changes: Hans-Dieter Sues Dinosaurian Faunas of the Later Mesozoic: Dale A. Russell and Jose F. Bonaparte The Extinction of the Dinosaurs: A Dialogue Between a Catastrophist and a Gradualist: Dale A. Russell and Peter Dodson PART SIX: DINOSAURS AND THE MEDIA Dinosaurs and the Media: Donald F. Glut and M. K. Brett-Surman APPENDIX: A CHRONOLOGICAL HISTORY OF DINOSAUR PALEONTOLOGY: M. K. Brett-Surman GLOSSARY CONTRIBUTORS INDEX

@book{openalexw1585246501,
    author = "Farlow, James O. and Brett-Surman, Michael K.",
    title = "The Complete Dinosaur",
    year = "2012",
    booktitle = "Opus: Research \& Creativity (Indiana University – Purdue University Fort Wayne)",
    abstract = "PREFACE: James O. Farlow and M. K. Brett-Surman PART ONE: THE DISCOVERY OF DINOSAURS The Earliest Discoveries: William A. S. Sarjeant European Dinosaur Hunters: Hans-Dieter Sues North American Dinosaur Hunters: Edwin H. Colbert Asian Dinosaur Hunters: John R. Lavas Dinosaur Hunters of the Southern Continents: Thomas R. Holtz, Jr. PART TWO: THE STUDY OF DINOSAURS Hunting for Dinosaur Bones: David D. Gillette The Osteology of the Dinosaurs: Thomas R. Holtz, Jr. and M. K.Brett-Surman The Taxonomy and Systematics of the Dinosaurs: Thomas R. Holtz, Jr. and M. K. Brett-Surman Dinosaurs and Geologic Time: James O. Farlow The Scientific Study of Dinosaurs: Ralph E. Chapman Molecular Paleontology: Rationale and Techniques for the Study of Ancient Biomolecules: Mary Higby Schweitzer Dinosaurs as Museum Exhibits: Kenneth Carpenter Restoring Dinosaurs as Living Animals: Douglas Henderson PART THREE: THE GROUPS OF DINOSAURS Introduction: James O. Farlow and M. K. Brett-Surman Politics and Paleontology: Richard Owen and the Invention of Dinosaurs: Hugh Torrens Evolution of the Archosaurs: J. Michael Parrish Origin and Early Evolution of Dinosaurs: Michael J. Benton Theropods: Philip J. Currie Segnosaurs (Therezinosaurs): Teresa Maryanska Prosauropods: Jacques VanHeerden Sauropods: John S. McIntosh, M. K. Brett-Surman, and James O. Farlow Stegosaurs: Peter M. Galton Ankylosaurs: Kenneth Carpenter Marginocephalians: Catherine A. Forster and Paul C. Sereno Ornithopods: M. K. Brett-Surman PART FOUR: BIOLOGY OF THE DINOSAURS Land Plants as Food and Habitat in the Age of Dinosaurs: Bruce H. Tiffney What Did Dinosaurs Eat? Coprolites and Other Direct Evidence of Dinosaur Diets: Karen Chin Dinosaur Combat and Courtship: Scott Sampson Dinosaur Eggs: Karl F. Hirsch and Darla K. Zelenitsky How Dinosaurs Grew: R. E. H. Reid Engineering a Dinosaur: R. McN. Alexander Dinosaurian Paleopathology: Bruce M. Rothschild Dinosaurian Physiology: the Case for Intermediate Dinosaurs: R. E. H. Reid Oxygen Isotopes in Dinosaur Bone: Reese E. Barrick, Michael K. Stoskopf, and William J. Showers A Blueprint for Giants: Do Living Reptiles, Birds or Mammals Provide the Best Model for the Physiology of Large Dinosaurs? Frank V. Paladino, James R. Spotila, and Peter Dodson New Insights into the Metabolic Physiology of Dinosaurs: John Ruben, Andrew Leitch, Willem Hillenius, Nicholas Geist, and Terry Jones The Scientific Study of Dinosaur Footprints: James O. Farlow and Ralph E. Chapman The Paleoecological and Paleoenvironmental Utility of Dinosaur Tracks: Martin G. Lockley PART FIVE: DINOSAUR EVOLUTION IN THE CHANGING WORLD OF THE MESOZOIC ERA Biogeography for Dinosaurs: Ralph E. Molnar Major Groups of Non-Dinosaurian Vertebrates of the Mesozoic Era: Michael Morales Continental Tetrapods of the Early Mesozoic: Faunas and Faunal Changes: Hans-Dieter Sues Dinosaurian Faunas of the Later Mesozoic: Dale A. Russell and Jose F. Bonaparte The Extinction of the Dinosaurs: A Dialogue Between a Catastrophist and a Gradualist: Dale A. Russell and Peter Dodson PART SIX: DINOSAURS AND THE MEDIA Dinosaurs and the Media: Donald F. Glut and M. K. Brett-Surman APPENDIX: A CHRONOLOGICAL HISTORY OF DINOSAUR PALEONTOLOGY: M. K. Brett-Surman GLOSSARY CONTRIBUTORS INDEX",
    openalex = "W1585246501",
    references = "chatterjee2013a, chinsamy1998polar, deklerk2000a, doi101002ar20982, doi101002ara10097, doi101002jmor10406, doi101007s0011400804883, doi1010160031018291900605, doi1010160034666781900695, doi101016jannpal200803002, doi101016jepsl200801015, doi101016jpalaeo201002025, doi101017cbo9780511608551, doi101017s0022336000018862, doi101017s0094837300007557, doi101017s0094837300016900, doi101017s0094837300021321, doi101038262207a0, doi101038307360a0, doi10103832884, doi101038359117a0, doi101038362709a0, doi101038368196a0, doi101038nature03635, doi101038nature10906, doi101046j14401738200300386x, doi10108002724634199810011086, doi10108002724634199910011125, doi10108008912960903503345, doi10108010420940802471027, doi101086284406, doi101086422766, doi101098rspb20060443, doi101111j10963642200600245x, doi101111j10963642200900631x, doi101111j1469185x200900107x, doi101111j150239311985tb00690x, doi101111j15023931200900187x, doi101126science1157704, doi101126science1180219, doi101126science172397867, doi101126science24248841403, doi101126science27352791204, doi101127njgpm19831983141, doi1011300091761319930210503pioatv23co2, doi101130g23452a1, doi101130spe40p1, doi101144001676492006032, doi101144gslsp20042280106, doi101146annurevearth040610133502, doi101146annurevearth28119, doi101146annurevgenet37110801143214, doi10120600030082200635301ydanpc20co2, doi1012066391, doi101353book59141, doi101371journalpone0012292, doi1016660094837320000260450fpindi20co2, doi1016660094837320050310291teafot20co2, doi1016690883135120030180286rpoumt20co2, doi1016710272463420020220593cvancf20co2, doi1016710272463420020220766tehits20co2, doi101671a11168, doi102110palo2007p07070r, doi1023071445147, doi1023073514548, doi102475ajss425149387, doi104202app20080049, doi105281zenodo13315375, doi105281zenodo16692311, doi105281zenodo3739898, doi105962p339375, fiorillo2004the, jacobsen1998feeding, lehman1987late, nelson1980counts, openalexw1550095290, openalexw1558456135, openalexw2163397885, openalexw2242116350, openalexw2506868775, pontzer2009biomechanics, russell2002synopsis, seymour1976dinosaurs, sloan1986gradual, stevens2006binocular, witmer1991biomechanics, woodward1910on"
}

@article{doi101007s1221001302589,
    author = "Pievani, Telmo",
    title = "The sixth mass extinction: Anthropocene and the human impact on biodiversity",
    year = "2013",
    journal = "RENDICONTI LINCEI",
    url = "https://doi.org/10.1007/s12210-013-0258-9",
    doi = "10.1007/s12210-013-0258-9",
    openalex = "W2061485087",
    references = "doi101016jcretres200805030, doi101666070341"
}

Mass extinctions manifest in Earth's geologic record were turning points in biotic evolution. We present (40)Ar/(39)Ar data that establish synchrony between the Cretaceous-Paleogene boundary and associated mass extinctions with the Chicxulub bolide impact to within 32,000 years. Perturbation of the atmospheric carbon cycle at the boundary likely lasted less than 5000 years, exhibiting a recovery time scale two to three orders of magnitude shorter than that of the major ocean basins. Low-diversity mammalian fauna in the western Williston Basin persisted for as little as 20,000 years after the impact. The Chicxulub impact likely triggered a state shift of ecosystems already under near-critical stress.

@article{doi101126science1230492,
    author = "Renne, Paul R. and Deino, Alan L. and Hilgen, F.J. and Kuiper, Klaudia F. and Mark, Darren F. and Mitchell, William S. and Morgan, Leah E. and Mundil, Roland and Smit, Jan",
    title = "Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary",
    year = "2013",
    journal = "Science",
    abstract = "Mass extinctions manifest in Earth's geologic record were turning points in biotic evolution. We present (40)Ar/(39)Ar data that establish synchrony between the Cretaceous-Paleogene boundary and associated mass extinctions with the Chicxulub bolide impact to within 32,000 years. Perturbation of the atmospheric carbon cycle at the boundary likely lasted less than 5000 years, exhibiting a recovery time scale two to three orders of magnitude shorter than that of the major ocean basins. Low-diversity mammalian fauna in the western Williston Basin persisted for as little as 20,000 years after the impact. The Chicxulub impact likely triggered a state shift of ecosystems already under near-critical stress.",
    url = "https://doi.org/10.1126/science.1230492",
    doi = "10.1126/science.1230492",
    openalex = "W1964523361",
    references = "doi101007s1091400569434, doi101016jchemgeo200503011, doi101016jcretres200805030, doi101016jepsl200902019, doi101016jepsl201107015, doi101016jgca2006061563, doi101016jgca201006017, doi101016jgca201106021, doi101016s0009254197001599, doi101016s0012821x03005570, doi101016s1631071303000063, doi1010292008jb005644, doi101038nature08227, doi101038nature11018, doi1010510004636120041335, doi10105100046361201116836, doi101073pnas802627, doi101126science1116412, doi101126science1154339, doi101126science1177265, doi101126science22346411177, doi101126science25250131690, doi101126science2575072954, doi1011270078042120120020, doi10113000917613198614279ssaedt20co2, doi1011300091761319910190867ccapct23co2, doi101130spe332, doi101146annurevecolsys35021103105715, doi101666070341, openalexw610180004"
}

The end-Triassic extinction is characterized by major losses in both terrestrial and marine diversity, setting the stage for dinosaurs to dominate Earth for the next 136 million years. Despite the approximate coincidence between this extinction and flood basalt volcanism, existing geochronologic dates have insufficient resolution to confirm eruptive rates required to induce major climate perturbations. Here, we present new zircon uranium-lead (U-Pb) geochronologic constraints on the age and duration of flood basalt volcanism within the Central Atlantic Magmatic Province. This chronology demonstrates synchroneity between the earliest volcanism and extinction, tests and corroborates the existing astrochronologic time scale, and shows that the release of magma and associated atmospheric flux occurred in four pulses over about 600,000 years, indicating expansive volcanism even as the biologic recovery was under way.

@article{doi101126science1234204,
    author = "Blackburn, Terrence and Olsen, Paul E. and Bowring, Samuel A. and McLean, Noah M. and Kent, Dennis V. and Puffer, John H. and McHone, G. and Rasbury, E. Troy and Et‐Touhami, Mohammed",
    title = "Zircon U-Pb Geochronology Links the End-Triassic Extinction with the Central Atlantic Magmatic Province",
    year = "2013",
    journal = "Science",
    abstract = "The end-Triassic extinction is characterized by major losses in both terrestrial and marine diversity, setting the stage for dinosaurs to dominate Earth for the next 136 million years. Despite the approximate coincidence between this extinction and flood basalt volcanism, existing geochronologic dates have insufficient resolution to confirm eruptive rates required to induce major climate perturbations. Here, we present new zircon uranium-lead (U-Pb) geochronologic constraints on the age and duration of flood basalt volcanism within the Central Atlantic Magmatic Province. This chronology demonstrates synchroneity between the earliest volcanism and extinction, tests and corroborates the existing astrochronologic time scale, and shows that the release of magma and associated atmospheric flux occurred in four pulses over about 600,000 years, indicating expansive volcanism even as the biologic recovery was under way.",
    url = "https://doi.org/10.1126/science.1234204",
    doi = "10.1126/science.1234204",
    openalex = "W2166913044",
    references = "doi101007s0041000600854, doi1010160031018295001719, doi101016jchemgeo200503011, doi101016jgca201006017, doi101016jgca201106021, doi101016s0009254199001576, doi101016s0016703799002045, doi101016s1631071303000063, doi1010291998rg000054, doi101093petrology3251021, doi101103physrevc41889, doi101126science1154339, doi101126science1208277, doi101126science1215507, doi101126science2845414616, doi101126science7701342, doi1011300091761320020300251tameat20co2, doi101130g306831"
}

A comprehensive review and study of the rich dinosaur track record of the Tremp Formation in the southern Pyrenees of Spain (Southwestern Europe) shows a unique succession of footprint localities prior to the end-Cretaceous mass extinction event. A description of some 30 new tracksites and data on sedimentary environments, track occurrence and preservation, ichnology and chronostratigraphy are provided. These new track localities represent various facies types within a diverse set of fluvial environments. The footprint discoveries mostly represent hadrosaurian and, less abundantly, to sauropod dinosaurs. The hadrosaur tracks are significantly smaller in size than, but morphologically similar to, those of North America and Asia and are attributable to the ichnogenus Hadrosauropodus. The track succession, with more than 40 distinct track levels, indicates that hadrosaur footprints in the Ibero-Armorican region occur predominantly in the late Maaastrichtian (at least above the early Maastrichtian-late Maastrichtian boundary). The highest abundance is found noticeably found in the late Maastrichtian, with tracks occurring in the C29r magnetochron, within about the latest 300,000 years of the Cretaceous.

@article{doi101371journalpone0072579,
    author = "Vila, Bernat and Oms, Oriol and Fondevilla, Víctor and Gaete, Rodrigo and Galobart, Àngel and Riera, V. and Canudo, José Ignacio",
    title = "The Latest Succession of Dinosaur Tracksites in Europe: Hadrosaur Ichnology, Track Production and Palaeoenvironments",
    year = "2013",
    journal = "PLoS ONE",
    abstract = "A comprehensive review and study of the rich dinosaur track record of the Tremp Formation in the southern Pyrenees of Spain (Southwestern Europe) shows a unique succession of footprint localities prior to the end-Cretaceous mass extinction event. A description of some 30 new tracksites and data on sedimentary environments, track occurrence and preservation, ichnology and chronostratigraphy are provided. These new track localities represent various facies types within a diverse set of fluvial environments. The footprint discoveries mostly represent hadrosaurian and, less abundantly, to sauropod dinosaurs. The hadrosaur tracks are significantly smaller in size than, but morphologically similar to, those of North America and Asia and are attributable to the ichnogenus Hadrosauropodus. The track succession, with more than 40 distinct track levels, indicates that hadrosaur footprints in the Ibero-Armorican region occur predominantly in the late Maaastrichtian (at least above the early Maastrichtian-late Maastrichtian boundary). The highest abundance is found noticeably found in the late Maastrichtian, with tracks occurring in the C29r magnetochron, within about the latest 300,000 years of the Cretaceous.",
    url = "https://doi.org/10.1371/journal.pone.0072579",
    doi = "10.1371/journal.pone.0072579",
    openalex = "W1968591108",
    references = "doi1010079783662032374, doi1010079789400904095, doi101007s0011400804990, doi101016b9780444594259000275, doi101016jpalaeo200909018, doi101016jpalaeo201206008, doi101017s0016756800012413, doi10108010420940490428625, doi101126science1177265, doi101126science1230492, doi1016710390290428, doi102110pec06840085, doi1023073514816, doi1026879264, doi105860choice393984, leloeuff1994the, openalexw114509570"
}

@article{doi101016jearscirev201410005,
    author = "Chen, Zhong‐Qiang and Yang, Hao and Luo, Mao and Benton, Michael J. and Kaiho, Kunio and Zhao, Laishi and Huang, Yuangeng and Kexing, Zhang and Fang, Yuheng and Jiang, Haishui and Qiu, Huan and Li, Yang and Tu, Chenyi and Shi, Lei and Zhang, Lei and Feng, Xueqian and Chen, Long",
    title = "Complete biotic and sedimentary records of the Permian–Triassic transition from Meishan section, South China: Ecologically assessing mass extinction and its aftermath",
    year = "2014",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/j.earscirev.2014.10.005",
    doi = "10.1016/j.earscirev.2014.10.005",
    openalex = "W2011947668",
    references = "doi101016jpalaeo200505019"
}

Changes in pollen and spore assemblages across the Cretaceous–Paleogene (K–Pg) boundary elucidate the vegetation response to a global environmental crisis triggered by an asteroid impact in Mexico 66 Ma. The Cretaceous–Paleogene boundary clay, associated with the Chicxulub asteroid impact event, constitutes a unique, global marker bed enabling comparison of the world-wide palynological signal spanning the mass extinction event. The data from both hemispheres are consistent, revealing diverse latest Cretaceous assemblages of pollen and spores that were affected by a major diversity loss as a consequence of the K–Pg event. Here we combine new results with past studies to provide an integrated global perspective of the terrestrial vegetation record across the K–Pg boundary. We further apply the K–Pg event as a template to asses the causal mechanism behind other major events in Earths history. The end-Permian, end-Triassic, and the K–Pg mass-extinctions were responses to different causal processes that resulted in essentially similar succession of decline and recovery phases, although expressed at different temporal scales. The events share a characteristic pattern of a bloom of opportunistic “crisis” tax followed by a pulse in pioneer communities, and finally a recovery in diversity including evolution of new taxa. Based on their similar extinction and recovery patterns and the fact that the Last and First Appearance Datums associated with the extinctions are separated in time, we recommend using the K–Pg event as a model and to use relative abundance data for the stratigraphic definition of mass-extinction events and the placement of associated chronostratigraphic boundaries.

@article{doi101016jgloplacha201407014,
    author = "Vajda, Vivi and Bercovici, Antoine",
    title = "The global vegetation pattern across the Cretaceous–Paleogene mass extinction interval: A template for other extinction events",
    year = "2014",
    journal = "Global and Planetary Change",
    abstract = "Changes in pollen and spore assemblages across the Cretaceous–Paleogene (K–Pg) boundary elucidate the vegetation response to a global environmental crisis triggered by an asteroid impact in Mexico 66 Ma. The Cretaceous–Paleogene boundary clay, associated with the Chicxulub asteroid impact event, constitutes a unique, global marker bed enabling comparison of the world-wide palynological signal spanning the mass extinction event. The data from both hemispheres are consistent, revealing diverse latest Cretaceous assemblages of pollen and spores that were affected by a major diversity loss as a consequence of the K–Pg event. Here we combine new results with past studies to provide an integrated global perspective of the terrestrial vegetation record across the K–Pg boundary. We further apply the K–Pg event as a template to asses the causal mechanism behind other major events in Earths history. The end-Permian, end-Triassic, and the K–Pg mass-extinctions were responses to different causal processes that resulted in essentially similar succession of decline and recovery phases, although expressed at different temporal scales. The events share a characteristic pattern of a bloom of opportunistic “crisis” tax followed by a pulse in pioneer communities, and finally a recovery in diversity including evolution of new taxa. Based on their similar extinction and recovery patterns and the fact that the Last and First Appearance Datums associated with the extinctions are separated in time, we recommend using the K–Pg event as a model and to use relative abundance data for the stratigraphic definition of mass-extinction events and the placement of associated chronostratigraphic boundaries.",
    url = "https://doi.org/10.1016/j.gloplacha.2014.07.014",
    doi = "10.1016/j.gloplacha.2014.07.014",
    openalex = "W2079006768",
    references = "doi101007s1091400569434, doi1010160034666780900226, doi101016jcretres200805030, doi101016jepsl200902019, doi101016jpalaeo200702037, doi101016jpalaeo201105050, doi101017cbo9780511535536, doi101038352420a0, doi101038ncomms1815, doi101073pnas1211526110, doi101073pnas1319253111, doi101073pnas802627, doi101080019161222012718609, doi10108003115517708527763, doi10108011035890902924877, doi101130spe247, doi101371journalpone0052455, doi1023073514678, hotton2002palynology, russell2002synopsis"
}

@article{doi101038ngeo2079,
    author = "Foster, William J. and Twitchett, Richard J.",
    title = "Functional diversity of marine ecosystems after the Late Permian mass extinction event",
    year = "2014",
    journal = "Nature Geoscience",
    url = "https://doi.org/10.1038/ngeo2079",
    doi = "10.1038/ngeo2079",
    openalex = "W2162618745",
    references = "doi101016jpalaeo200505019, doi101146annurevearth040809152556"
}

The mass extinction at the Cretaceous-Paleogene boundary, ∼ 66 Ma, is thought to be caused by the impact of an asteroid at Chicxulub, present-day Mexico. Although the precise mechanisms that led to this mass extinction remain enigmatic, most postulated scenarios involve a short-lived global cooling, a so-called "impact winter" phase. Here we document a major decline in sea surface temperature during the first months to decades following the impact event, using TEX86 paleothermometry of sediments from the Brazos River section, Texas. We interpret this cold spell to reflect, to our knowledge, the first direct evidence for the effects of the formation of dust and aerosols by the impact and their injection in the stratosphere, blocking incoming solar radiation. This impact winter was likely a major driver of mass extinction because of the resulting global decimation of marine and continental photosynthesis.

@article{doi101073pnas1319253111,
    author = "Vellekoop, Johan and Sluijs, Appy and Smit, Jan and Schouten, Stefan and Weijers, Johan W.H. and Damsté, Jaap S. Sinninghe and Brinkhuis, Henk",
    title = "Rapid short-term cooling following the Chicxulub impact at the Cretaceous–Paleogene boundary",
    year = "2014",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = {The mass extinction at the Cretaceous-Paleogene boundary, ∼ 66 Ma, is thought to be caused by the impact of an asteroid at Chicxulub, present-day Mexico. Although the precise mechanisms that led to this mass extinction remain enigmatic, most postulated scenarios involve a short-lived global cooling, a so-called "impact winter" phase. Here we document a major decline in sea surface temperature during the first months to decades following the impact event, using TEX86 paleothermometry of sediments from the Brazos River section, Texas. We interpret this cold spell to reflect, to our knowledge, the first direct evidence for the effects of the formation of dust and aerosols by the impact and their injection in the stratosphere, blocking incoming solar radiation. This impact winter was likely a major driver of mass extinction because of the resulting global decimation of marine and continental photosynthesis.},
    url = "https://doi.org/10.1073/pnas.1319253111",
    doi = "10.1073/pnas.1319253111",
    openalex = "W2105771959",
    references = "alvarez1980extraterrestrial, doi101016jgca201005027, doi101016jorggeochem200607018, doi101016jpalaeo200702037, doi101016s0012821x02009792, doi10102997je01743, doi101038285198a0, doi10103835097000, doi101073pnas0802597105, doi101126science1177265, doi101126science2414865567, doi101130081372356655, doi101146annurevearth33092203122654, ganapathy1981iridium"
}

Non-avian dinosaurs went extinct 66 million years ago, geologically coincident with the impact of a large bolide (comet or asteroid) during an interval of massive volcanic eruptions and changes in temperature and sea level. There has long been fervent debate about how these events affected dinosaurs. We review a wealth of new data accumulated over the past two decades, provide updated and novel analyses of long-term dinosaur diversity trends during the latest Cretaceous, and discuss an emerging consensus on the extinction's tempo and causes. Little support exists for a global, long-term decline across non-avian dinosaur diversity prior to their extinction at the end of the Cretaceous. However, restructuring of latest Cretaceous dinosaur faunas in North America led to reduced diversity of large-bodied herbivores, perhaps making communities more susceptible to cascading extinctions. The abruptness of the dinosaur extinction suggests a key role for the bolide impact, although the coarseness of the fossil record makes testing the effects of Deccan volcanism difficult.

@article{doi101111brv12128,
    author = "Brusatte, Stephen L. and Butler, Richard J. and Barrett, Paul M. and Carrano, Matthew T. and Evans, David C. and Lloyd, Graeme T. and Mannion, Philip D. and Norell, Mark A. and Peppe, Daniel J. and Upchurch, Paul and Williamson, Thomas E.",
    title = "The extinction of the dinosaurs",
    year = "2014",
    journal = "Biological reviews/Biological reviews of the Cambridge Philosophical Society",
    abstract = "Non-avian dinosaurs went extinct 66 million years ago, geologically coincident with the impact of a large bolide (comet or asteroid) during an interval of massive volcanic eruptions and changes in temperature and sea level. There has long been fervent debate about how these events affected dinosaurs. We review a wealth of new data accumulated over the past two decades, provide updated and novel analyses of long-term dinosaur diversity trends during the latest Cretaceous, and discuss an emerging consensus on the extinction's tempo and causes. Little support exists for a global, long-term decline across non-avian dinosaur diversity prior to their extinction at the end of the Cretaceous. However, restructuring of latest Cretaceous dinosaur faunas in North America led to reduced diversity of large-bodied herbivores, perhaps making communities more susceptible to cascading extinctions. The abruptness of the dinosaur extinction suggests a key role for the bolide impact, although the coarseness of the fossil record makes testing the effects of Deccan volcanism difficult.",
    url = "https://doi.org/10.1111/brv.12128",
    doi = "10.1111/brv.12128",
    openalex = "W1515034626",
    references = "alvarez1980extraterrestrial, doi101007s0011400804990, doi101007s1091400569434, doi101016jpalaeo200702037, doi101016jpalaeo200909018, doi101016jpalaeo201206024, doi101016jpalaeo201206027, doi101016s0012825200000374, doi101016s1631071303000063, doi101038ncomms1815, doi101073pnas1211526110, doi101080027246342010483632, doi101126science1116412, doi101126science1156963, doi101126science1177265, doi101126science28454232137, doi1011300091761319910190867ccapct23co2, doi1011300091761320020300123dsproe20co2, doi101139cjes20120185, doi101371journalpone0016574, doi101371journalpone0025186, doi101371journalpone0072579, doi1015259780520941434, doi10166612041, doi102475ajss32313381, horner2011dinosaur, lofgren1990reworking, openalexw2183707334, sloan1986gradual"
}

The Chicxulub asteroid impact (Mexico) and the eruption of the massive Deccan volcanic province (India) are two proposed causes of the end-Cretaceous mass extinction, which includes the demise of nonavian dinosaurs. Despite widespread acceptance of the impact hypothesis, the lack of a high-resolution eruption timeline for the Deccan basalts has prevented full assessment of their relationship to the mass extinction. Here we apply uranium-lead (U-Pb) zircon geochronology to Deccan rocks and show that the main phase of eruptions initiated ~250,000 years before the Cretaceous-Paleogene boundary and that >1.1 million cubic kilometers of basalt erupted in ~750,000 years. Our results are consistent with the hypothesis that the Deccan Traps contributed to the latest Cretaceous environmental change and biologic turnover that culminated in the marine and terrestrial mass extinctions.

@article{doi101126scienceaaa0118,
    author = "Schoene, Blair and Samperton, Kyle M. and Eddy, Michael P. and Keller, Gerta and Adatte, Thierry and Bowring, Samuel A. and Khadri, S. and Gertsch, B.",
    title = "U-Pb geochronology of the Deccan Traps and relation to the end-Cretaceous mass extinction",
    year = "2014",
    journal = "Science",
    abstract = "The Chicxulub asteroid impact (Mexico) and the eruption of the massive Deccan volcanic province (India) are two proposed causes of the end-Cretaceous mass extinction, which includes the demise of nonavian dinosaurs. Despite widespread acceptance of the impact hypothesis, the lack of a high-resolution eruption timeline for the Deccan basalts has prevented full assessment of their relationship to the mass extinction. Here we apply uranium-lead (U-Pb) zircon geochronology to Deccan rocks and show that the main phase of eruptions initiated \textasciitilde 250,000 years before the Cretaceous-Paleogene boundary and that >1.1 million cubic kilometers of basalt erupted in \textasciitilde 750,000 years. Our results are consistent with the hypothesis that the Deccan Traps contributed to the latest Cretaceous environmental change and biologic turnover that culminated in the marine and terrestrial mass extinctions.",
    url = "https://doi.org/10.1126/science.aaa0118",
    doi = "10.1126/science.aaa0118",
    openalex = "W2009674195",
    references = "doi101007s0041000203647, doi1010160009254194001404, doi1010160012821x8390211x, doi1010160016703773902135, doi101016b9780080959757003107, doi101016jchemgeo200503011, doi101016jepsl200902019, doi101016jgca201006017, doi101016s0009254197001599, doi101016s0012821x0000159x, doi101016s1631071303000063, doi1010292006gc001492, doi1010292008jb005644, doi101103physrevc41889, doi101126science1097329, doi101126science1154339, doi101126science1177265, doi101126science1215507, doi101126science1230492, doi101126science1234204, doi1011300091761319980260995adswat23co2, doi1011302014250315, doi101130b309291, doi101130g306831, doi101144gsjgs15420265"
}

@article{doi101016jpalaeo201507002,
    author = "Zhang, Hua and Cao, Changqun and Liu, Xiaolei and Mu, Lin and Zheng, Quan-feng and Liu, Feng and Xiang, Lei and Liu, Lujun and Shen, Shu‐zhong",
    title = "The terrestrial end-Permian mass extinction in South China",
    year = "2015",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2015.07.002",
    doi = "10.1016/j.palaeo.2015.07.002",
    openalex = "W2198101982",
    references = "doi101016jpalaeo201401002, doi101111j14724669201100305x"
}

Bolide impact and flood volcanism compete as leading candidates for the cause of terminal-Cretaceous mass extinctions. High-precision (40)Ar/(39)Ar data indicate that these two mechanisms may be genetically related, and neither can be considered in isolation. The existing Deccan Traps magmatic system underwent a state shift approximately coincident with the Chicxulub impact and the terminal-Cretaceous mass extinctions, after which ~70% of the Traps' total volume was extruded in more massive and more episodic eruptions. Initiation of this new regime occurred within ~50,000 years of the impact, which is consistent with transient effects of impact-induced seismic energy. Postextinction recovery of marine ecosystems was probably suppressed until after the accelerated volcanism waned.

@article{doi101126scienceaac7549,
    author = "Renne, Paul R. and Sprain, Courtney J. and Richards, Mark A. and Self, Stephen and Vanderkluysen, L. and Pande, Kanchan",
    title = "State shift in Deccan volcanism at the Cretaceous-Paleogene boundary, possibly induced by impact",
    year = "2015",
    journal = "Science",
    abstract = "Bolide impact and flood volcanism compete as leading candidates for the cause of terminal-Cretaceous mass extinctions. High-precision (40)Ar/(39)Ar data indicate that these two mechanisms may be genetically related, and neither can be considered in isolation. The existing Deccan Traps magmatic system underwent a state shift approximately coincident with the Chicxulub impact and the terminal-Cretaceous mass extinctions, after which \textasciitilde 70\% of the Traps' total volume was extruded in more massive and more episodic eruptions. Initiation of this new regime occurred within \textasciitilde 50,000 years of the impact, which is consistent with transient effects of impact-induced seismic energy. Postextinction recovery of marine ecosystems was probably suppressed until after the accelerated volcanism waned.",
    url = "https://doi.org/10.1126/science.aac7549",
    doi = "10.1126/science.aac7549",
    openalex = "W2198827077",
    references = "doi101016jcretres200805030, doi101016jgca201106021, doi101016s0012821x0000159x, doi1010292008jb005644, doi101126science1230492, doi101126scienceaaa0118, doi101130b310761"
}

The temporal link between large igneous province (LIP) eruptions and at least half of the major extinctions of the Phanerozoic implies that large scale volcanism is the main driver of mass extinction. Here we review almost twenty biotic crises between the early Cambrian and end Cretaceous and explore potential causal mechanisms. Most extinctions are associated with global warming and proximal killers such as marine anoxia (including the Early/Middle Cambrian, the Late Ordovician, the intra-Silurian, intra-Devonian, end-Permian, and Early Jurassic crises). Many, but not all of these are accompanied by large negative carbon isotope excursions, supporting a volcanogenic origin. Most post-Silurian biocrises affected both terrestrial and marine biospheres, suggesting that atmospheric processes were crucial in driving global extinctions. Volcanogenic-atmospheric kill mechanisms include ocean acidification, toxic metal poisoning, acid rain, and ozone damage and consequent increased UV-B radiation, volcanic darkness, cooling and photosynthetic shutdown, each of which has been implicated in numerous events. Intriguingly, some of the most voluminous LIPs such as the oceanic plateaus of the Cretaceous were emplaced with minimal faunal losses and so volume of magma is not the only factor governing LIP lethality. The missing link might be continental configuration because the best examples of the LIP/extinction relationship occurred during the time of Pangaea. Many of the proximal kill mechanisms in LIP/extinction scenarios are also potential effects of bolide impact, including cooling, warming, acidification and ozone destruction. However, the absence of convincing temporal links between impacts and extinctions other than the Chicxulub-Cretaceous example, suggests that impacts are not the main driver of extinctions. With numerous competing extinction scenarios, and the realisation that some of the purported environmental stresses may once again be driving mass extinction, we explore how experimental biology might inform our understanding of ancient extinctions as well as future crises.

@article{doi101016jpalaeo201611005,
    author = "Bond, David P.G. and Grasby, Stephen E.",
    title = "On the causes of mass extinctions",
    year = "2016",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    abstract = "The temporal link between large igneous province (LIP) eruptions and at least half of the major extinctions of the Phanerozoic implies that large scale volcanism is the main driver of mass extinction. Here we review almost twenty biotic crises between the early Cambrian and end Cretaceous and explore potential causal mechanisms. Most extinctions are associated with global warming and proximal killers such as marine anoxia (including the Early/Middle Cambrian, the Late Ordovician, the intra-Silurian, intra-Devonian, end-Permian, and Early Jurassic crises). Many, but not all of these are accompanied by large negative carbon isotope excursions, supporting a volcanogenic origin. Most post-Silurian biocrises affected both terrestrial and marine biospheres, suggesting that atmospheric processes were crucial in driving global extinctions. Volcanogenic-atmospheric kill mechanisms include ocean acidification, toxic metal poisoning, acid rain, and ozone damage and consequent increased UV-B radiation, volcanic darkness, cooling and photosynthetic shutdown, each of which has been implicated in numerous events. Intriguingly, some of the most voluminous LIPs such as the oceanic plateaus of the Cretaceous were emplaced with minimal faunal losses and so volume of magma is not the only factor governing LIP lethality. The missing link might be continental configuration because the best examples of the LIP/extinction relationship occurred during the time of Pangaea. Many of the proximal kill mechanisms in LIP/extinction scenarios are also potential effects of bolide impact, including cooling, warming, acidification and ozone destruction. However, the absence of convincing temporal links between impacts and extinctions other than the Chicxulub-Cretaceous example, suggests that impacts are not the main driver of extinctions. With numerous competing extinction scenarios, and the realisation that some of the purported environmental stresses may once again be driving mass extinction, we explore how experimental biology might inform our understanding of ancient extinctions as well as future crises.",
    url = "https://doi.org/10.1016/j.palaeo.2016.11.005",
    doi = "10.1016/j.palaeo.2016.11.005",
    openalex = "W2552047291",
    references = "alvarez1980extraterrestrial, doi101007bf01821208, doi1010160031018284900415, doi1010160034666780900226, doi101016jearscirev200708008, doi101016jearscirev200910009, doi101016jepsl200905028, doi101016jgca201006017, doi101016jgca201106021, doi101016jgeobios201111001, doi101016jpalaeo200507010, doi101016jpalaeo200702037, doi101016jpalaeo201703014, doi101016s0012825202001046, doi101016s0031018298001175, doi101016s0169534703000934, doi101016s0967065397848259, doi101017s0016756807003895, doi101017s0094837300003778, doi1010291998rg000054, doi10102996rg03038, doi10102997je01743, doi101029gb002i004p00299, doi101038227930a0, doi101038367231a0, doi101038nature04095, doi101038nature09678, doi101038ngeo1475, doi101038ngeo1649, doi101073pnas1110395108, doi101073pnas1211526110, doi10108010292389409380462, doi101086648217, doi101098rstb19890092, doi101098rstb19980195, doi101111j150239312002tb00081x, doi101126sciadv1400253, doi101126science1097329, doi101126science1213454, doi101126science1230492, doi101126science1234204, doi101126science20844481095, doi101126science21545391501, doi101126scienceaaa0118, doi10113000167606198596567defie20co2, doi1011300091761319910190867ccapct23co2, doi1011300091761319950230495ejmeag23co2, doi1011300091761319980260995adswat23co2, doi1011300091761320020300251tameat20co2, doi101130081372356655, doi1011302014250502, doi101130g322301, doi101130g327071, doi101130spe89p63, doi101144gsjgs15420265, doi101146annurevearth042711105329, doi1016660094837320040300522oeamdo20co2, openalexw1832764887, openalexw2596223166"
}

The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8±3.3 °C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change.

@article{doi101038ncomms12079,
    author = "Petersen, Sierra and Dutton, Andrea and Lohmann, Kyger C.",
    title = "End-Cretaceous extinction in Antarctica linked to both Deccan volcanism and meteorite impact via climate change",
    year = "2016",
    journal = "Nature Communications",
    abstract = "The cause of the end-Cretaceous (KPg) mass extinction is still debated due to difficulty separating the influences of two closely timed potential causal events: eruption of the Deccan Traps volcanic province and impact of the Chicxulub meteorite. Here we combine published extinction patterns with a new clumped isotope temperature record from a hiatus-free, expanded KPg boundary section from Seymour Island, Antarctica. We document a 7.8±3.3 °C warming synchronous with the onset of Deccan Traps volcanism and a second, smaller warming at the time of meteorite impact. Local warming may have been amplified due to simultaneous disappearance of continental or sea ice. Intra-shell variability indicates a possible reduction in seasonality after Deccan eruptions began, continuing through the meteorite event. Species extinction at Seymour Island occurred in two pulses that coincide with the two observed warming events, directly linking the end-Cretaceous extinction at this site to both volcanic and meteorite events via climate change.",
    url = "https://doi.org/10.1038/ncomms12079",
    doi = "10.1038/ncomms12079",
    openalex = "W2465856649",
    references = "doi101016jgloplacha201312007, doi1011300091761319980260995adswat23co2, doi101666070341"
}

It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous–Palaeogene (K–Pg) extinction event. We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10–20 Myr prior to the K–Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K–Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K–Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.

@article{doi101098rspb20160256,
    author = "Grossnickle, David M. and Newham, Elis",
    title = "Therian mammals experience an ecomorphological radiation during the Late Cretaceous and selective extinction at the K–Pg boundary",
    year = "2016",
    journal = "Proceedings of the Royal Society B Biological Sciences",
    abstract = "It is often postulated that mammalian diversity was suppressed during the Mesozoic Era and increased rapidly after the Cretaceous–Palaeogene (K–Pg) extinction event. We test this hypothesis by examining macroevolutionary patterns in early therian mammals, the group that gave rise to modern placentals and marsupials. We assess morphological disparity and dietary trends using morphometric analyses of lower molars, and we evaluate generic level taxonomic diversity patterns using techniques that account for sampling biases. In contrast with the suppression hypothesis, our results suggest that an ecomorphological diversification of therians began 10–20 Myr prior to the K–Pg extinction event, led by disparate metatherians and Eurasian faunas. This diversification is concurrent with ecomorphological radiations of multituberculate mammals and flowering plants, suggesting that mammals as a whole benefitted from the ecological rise of angiosperms. In further contrast with the suppression hypothesis, therian disparity decreased immediately after the K–Pg boundary, probably due to selective extinction against ecological specialists and metatherians. However, taxonomic diversity trends appear to have been decoupled from disparity patterns, remaining low in the Cretaceous and substantially increasing immediately after the K–Pg extinction event. The conflicting diversity and disparity patterns suggest that earliest Palaeocene extinction survivors, especially eutherian dietary generalists, underwent rapid taxonomic diversification without considerable morphological diversification.",
    url = "https://doi.org/10.1098/rspb.2016.0256",
    doi = "10.1098/rspb.2016.0256",
    openalex = "W2412707313",
    references = "doi101098rspb20132110, doi101111brv12164, doi1011302014250315, doi1012066231, doi10166612041"
}

@article{doi101016jgr201712002,
    author = "Keller, Gerta and Mateo, Paula and Punekar, Jahnavi and Khozyem, Hassan and Gertsch, B. and Spangenberg, Jorge E. and Bitchong, André Mbabi and Adatte, Thierry",
    title = "Environmental changes during the Cretaceous-Paleogene mass extinction and Paleocene-Eocene Thermal Maximum: Implications for the Anthropocene",
    year = "2017",
    journal = "Gondwana Research",
    url = "https://doi.org/10.1016/j.gr.2017.12.002",
    doi = "10.1016/j.gr.2017.12.002",
    openalex = "W2780054537",
    references = "doi101007s1091400569434, doi101016jepsl200801015, doi101016s003101820100476x, doi101016s0031018203005728, doi101016s0377839803000215, doi1011302014250315"
}

@article{doi101016jpalaeo201703014,
    author = "Ernst, Richard E. and Youbi, Nasrrddine",
    title = "How Large Igneous Provinces affect global climate, sometimes cause mass extinctions, and represent natural markers in the geological record",
    year = "2017",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/j.palaeo.2017.03.014",
    doi = "10.1016/j.palaeo.2017.03.014",
    openalex = "W2602434750",
    references = "alvarez1980extraterrestrial, doi101007978364270831215, doi101016c20090644421, doi101016jearscirev200708008, doi101016jgloplacha201312007, doi101016jpalaeo200706013, doi101016jpalaeo201005036, doi101016jpalaeo201611005, doi101016jprecamres200704021, doi1010179781316225523, doi1010291998rg000054, doi1010292008jb005644, doi1010292009gc002788, doi101029jc086ic10p09776, doi101038nature02599, doi101038nature13068, doi10108008120090500170393, doi101098rstb19980195, doi101126science1116412, doi101126science1161648, doi101126science1183325, doi101126science1214697, doi101126science1234204, doi101126science21545391501, doi101126science23547931156, doi101126scienceaaa0118, doi1011270078042120120020, doi1011300091761319910190867ccapct23co2, doi1011302014250502, doi101130g306831, doi101146annurevearth33092203122654, doi104202app20110058, doi105860choice465038"
}

Mass extinction events are short-lived and characterized by catastrophic biosphere collapse and subsequent reorganization. Their abrupt nature necessitates a similarly short-lived trigger, and large igneous province magmatism is often implicated. However, large igneous provinces are long-lived compared to mass extinctions. Therefore, if large igneous provinces are an effective trigger, a subinterval of magmatism must be responsible for driving deleterious environmental effects. The onset of Earth's most severe extinction, the end-Permian, coincided with an abrupt change in the emplacement style of the contemporaneous Siberian Traps large igneous province, from dominantly flood lavas to sill intrusions. Here we identify the initial emplacement pulse of laterally extensive sills as the critical deadly interval. Heat from these sills exposed untapped volatile-fertile sediments to contact metamorphism, likely liberating the massive greenhouse gas volumes needed to drive extinction. These observations suggest that large igneous provinces characterized by sill complexes are more likely to trigger catastrophic global environmental change than their flood basalt- and/or dike-dominated counterparts.Although the mass end-Permian extinction is linked to large igneous provinces, its trigger remains unclear. Here, the authors propose that the abrupt change from flood lavas to sills resulted in the heating of sediments and led to the release of large-scale greenhouse gases to drive the end-Permian extinction.

@article{doi101038s41467017000839,
    author = "Burgess, Seth D. and Muirhead, James D. and Bowring, Samuel A.",
    title = "Initial pulse of Siberian Traps sills as the trigger of the end-Permian mass extinction",
    year = "2017",
    journal = "Nature Communications",
    abstract = "Mass extinction events are short-lived and characterized by catastrophic biosphere collapse and subsequent reorganization. Their abrupt nature necessitates a similarly short-lived trigger, and large igneous province magmatism is often implicated. However, large igneous provinces are long-lived compared to mass extinctions. Therefore, if large igneous provinces are an effective trigger, a subinterval of magmatism must be responsible for driving deleterious environmental effects. The onset of Earth's most severe extinction, the end-Permian, coincided with an abrupt change in the emplacement style of the contemporaneous Siberian Traps large igneous province, from dominantly flood lavas to sill intrusions. Here we identify the initial emplacement pulse of laterally extensive sills as the critical deadly interval. Heat from these sills exposed untapped volatile-fertile sediments to contact metamorphism, likely liberating the massive greenhouse gas volumes needed to drive extinction. These observations suggest that large igneous provinces characterized by sill complexes are more likely to trigger catastrophic global environmental change than their flood basalt- and/or dike-dominated counterparts.Although the mass end-Permian extinction is linked to large igneous provinces, its trigger remains unclear. Here, the authors propose that the abrupt change from flood lavas to sills resulted in the heating of sediments and led to the release of large-scale greenhouse gases to drive the end-Permian extinction.",
    url = "https://doi.org/10.1038/s41467-017-00083-9",
    doi = "10.1038/s41467-017-00083-9",
    openalex = "W2737540514",
    references = "doi101016jpalaeo201005036, doi101016jpalaeo201611005, doi101016jpalaeo201703014, doi101126science1213454, doi101126science1230492, doi101126science1234204, doi101126scienceaaa0118, doi101130g306831"
}

Frogs (Anura) are one of the most diverse groups of vertebrates and comprise nearly 90% of living amphibian species. Their worldwide distribution and diverse biology make them well-suited for assessing fundamental questions in evolution, ecology, and conservation. However, despite their scientific importance, the evolutionary history and tempo of frog diversification remain poorly understood. By using a molecular dataset of unprecedented size, including 88-kb characters from 95 nuclear genes of 156 frog species, in conjunction with 20 fossil-based calibrations, our analyses result in the most strongly supported phylogeny of all major frog lineages and provide a timescale of frog evolution that suggests much younger divergence times than suggested by earlier studies. Unexpectedly, our divergence-time analyses show that three species-rich clades (Hyloidea, Microhylidae, and Natatanura), which together comprise ∼88% of extant anuran species, simultaneously underwent rapid diversification at the Cretaceous-Paleogene (K-Pg) boundary (KPB). Moreover, anuran families and subfamilies containing arboreal species originated near or after the KPB. These results suggest that the K-Pg mass extinction may have triggered explosive radiations of frogs by creating new ecological opportunities. This phylogeny also reveals relationships such as Microhylidae being sister to all other ranoid frogs and African continental lineages of Natatanura forming a clade that is sister to a clade of Eurasian, Indian, Melanesian, and Malagasy lineages. Biogeographical analyses suggest that the ancestral area of modern frogs was Africa, and their current distribution is largely associated with the breakup of Pangaea and subsequent Gondwanan fragmentation.

@article{doi101073pnas1704632114,
    author = "Feng, Yanjie and Blackburn, David C. and Liang, Dan and Hillis, David M. and Wake, David B. and Cannatella, David C. and Zhang, Peng",
    title = "Phylogenomics reveals rapid, simultaneous diversification of three major clades of Gondwanan frogs at the Cretaceous–Paleogene boundary",
    year = "2017",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Frogs (Anura) are one of the most diverse groups of vertebrates and comprise nearly 90\% of living amphibian species. Their worldwide distribution and diverse biology make them well-suited for assessing fundamental questions in evolution, ecology, and conservation. However, despite their scientific importance, the evolutionary history and tempo of frog diversification remain poorly understood. By using a molecular dataset of unprecedented size, including 88-kb characters from 95 nuclear genes of 156 frog species, in conjunction with 20 fossil-based calibrations, our analyses result in the most strongly supported phylogeny of all major frog lineages and provide a timescale of frog evolution that suggests much younger divergence times than suggested by earlier studies. Unexpectedly, our divergence-time analyses show that three species-rich clades (Hyloidea, Microhylidae, and Natatanura), which together comprise ∼88\% of extant anuran species, simultaneously underwent rapid diversification at the Cretaceous-Paleogene (K-Pg) boundary (KPB). Moreover, anuran families and subfamilies containing arboreal species originated near or after the KPB. These results suggest that the K-Pg mass extinction may have triggered explosive radiations of frogs by creating new ecological opportunities. This phylogeny also reveals relationships such as Microhylidae being sister to all other ranoid frogs and African continental lineages of Natatanura forming a clade that is sister to a clade of Eurasian, Indian, Melanesian, and Malagasy lineages. Biogeographical analyses suggest that the ancestral area of modern frogs was Africa, and their current distribution is largely associated with the breakup of Pangaea and subsequent Gondwanan fragmentation.",
    url = "https://doi.org/10.1073/pnas.1704632114",
    doi = "10.1073/pnas.1704632114",
    openalex = "W2731841059",
    references = "doi101073pnas1110395108, doi101073pnas1211526110, doi101126science1064706, doi101126science1229237, doi101126science1230492, doi1012060003009020062970001tatol20co2, doi1026879424"
}

@article{doi101016jgr201805007,
    author = "Heindel, Katrin and Foster, William J. and Richoz, Sylvain and Birgel, Daniel and Roden, Vanessa Julie and Baud, Aymon and Brandner, Rainer and Krystyn, Leopold and Mohtat, Tayebeh and Koşun, Erdal and Twitchett, Richard J. and Reitner, Joachim and Peckmann, Jörn",
    title = "The formation of microbial-metazoan bioherms and biostromes following the latest Permian mass extinction",
    year = "2018",
    journal = "Gondwana Research",
    url = "https://doi.org/10.1016/j.gr.2018.05.007",
    doi = "10.1016/j.gr.2018.05.007",
    openalex = "W2808657626",
    references = "doi10108001490450490438757, doi101111j14724669201100305x"
}

Mass extinction at the Cretaceous-Paleogene (K-Pg) boundary coincides with the Chicxulub bolide impact and also falls within the broader time frame of Deccan trap emplacement. Critically, though, empirical evidence as to how either of these factors could have driven observed extinction patterns and carbon cycle perturbations is still lacking. Here, using boron isotopes in foraminifera, we document a geologically rapid surface-ocean pH drop following the Chicxulub impact, supporting impact-induced ocean acidification as a mechanism for ecological collapse in the marine realm. Subsequently, surface water pH rebounded sharply with the extinction of marine calcifiers and the associated imbalance in the global carbon cycle. Our reconstructed water-column pH gradients, combined with Earth system modeling, indicate that a partial ∼50% reduction in global marine primary productivity is sufficient to explain observed marine carbon isotope patterns at the K-Pg, due to the underlying action of the solubility pump. While primary productivity recovered within a few tens of thousands of years, inefficiency in carbon export to the deep sea lasted much longer. This phased recovery scenario reconciles competing hypotheses previously put forward to explain the K-Pg carbon isotope records, and explains both spatially variable patterns of change in marine productivity across the event and a lack of extinction at the deep sea floor. In sum, we provide insights into the drivers of the last mass extinction, the recovery of marine carbon cycling in a postextinction world, and the way in which marine life imprints its isotopic signal onto the geological record.

@article{doi101073pnas1905989116,
    author = "Henehan, Michael J. and Ridgwell, Andy and Thomas, Ellen and Zhang, Shuang and Alegret, Laia and Schmidt, Daniela N. and Rae, James and Witts, James D. and Landman, Neil H. and Greene, Sarah E. and Huber, Brian T. and Super, J. R. and Planavsky, Noah J. and Hull, Pincelli M.",
    title = "Rapid ocean acidification and protracted Earth system recovery followed the end-Cretaceous Chicxulub impact",
    year = "2019",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Mass extinction at the Cretaceous-Paleogene (K-Pg) boundary coincides with the Chicxulub bolide impact and also falls within the broader time frame of Deccan trap emplacement. Critically, though, empirical evidence as to how either of these factors could have driven observed extinction patterns and carbon cycle perturbations is still lacking. Here, using boron isotopes in foraminifera, we document a geologically rapid surface-ocean pH drop following the Chicxulub impact, supporting impact-induced ocean acidification as a mechanism for ecological collapse in the marine realm. Subsequently, surface water pH rebounded sharply with the extinction of marine calcifiers and the associated imbalance in the global carbon cycle. Our reconstructed water-column pH gradients, combined with Earth system modeling, indicate that a partial ∼50\% reduction in global marine primary productivity is sufficient to explain observed marine carbon isotope patterns at the K-Pg, due to the underlying action of the solubility pump. While primary productivity recovered within a few tens of thousands of years, inefficiency in carbon export to the deep sea lasted much longer. This phased recovery scenario reconciles competing hypotheses previously put forward to explain the K-Pg carbon isotope records, and explains both spatially variable patterns of change in marine productivity across the event and a lack of extinction at the deep sea floor. In sum, we provide insights into the drivers of the last mass extinction, the recovery of marine carbon cycling in a postextinction world, and the way in which marine life imprints its isotopic signal onto the geological record.",
    url = "https://doi.org/10.1073/pnas.1905989116",
    doi = "10.1073/pnas.1905989116",
    openalex = "W2980427729",
    references = "doi101016jgloplacha201901020, doi101016jpalaeo200702037, doi101126scienceaau2422"
}

Temporal correlation between some continental flood basalt eruptions and mass extinctions has been proposed to indicate causality, with eruptive volatile release driving environmental degradation and extinction. We tested this model for the Deccan Traps flood basalt province, which, along with the Chicxulub bolide impact, is implicated in the Cretaceous-Paleogene (K-Pg) extinction approximately 66 million years ago. We estimated Deccan eruption rates with uranium-lead (U-Pb) zircon geochronology and resolved four high-volume eruptive periods. According to this model, maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction. These findings support extinction models that incorporate both catastrophic events as drivers of environmental deterioration associated with the K-Pg extinction and its aftermath.

@article{doi101126scienceaau2422,
    author = "Schoene, Blair and Eddy, Michael P. and Samperton, Kyle M. and Keller, C. Brenhin and Keller, Gerta and Adatte, Thierry and Khadri, S.",
    title = "U-Pb constraints on pulsed eruption of the Deccan Traps across the end-Cretaceous mass extinction",
    year = "2019",
    journal = "Science",
    abstract = "Temporal correlation between some continental flood basalt eruptions and mass extinctions has been proposed to indicate causality, with eruptive volatile release driving environmental degradation and extinction. We tested this model for the Deccan Traps flood basalt province, which, along with the Chicxulub bolide impact, is implicated in the Cretaceous-Paleogene (K-Pg) extinction approximately 66 million years ago. We estimated Deccan eruption rates with uranium-lead (U-Pb) zircon geochronology and resolved four high-volume eruptive periods. According to this model, maximum eruption rates occurred before and after the K-Pg extinction, with one such pulse initiating tens of thousands of years prior to both the bolide impact and extinction. These findings support extinction models that incorporate both catastrophic events as drivers of environmental deterioration associated with the K-Pg extinction and its aftermath.",
    url = "https://doi.org/10.1126/science.aau2422",
    doi = "10.1126/science.aau2422",
    openalex = "W2915414273",
    references = "doi1010160016703773902135, doi101016jchemgeo200210001, doi101016jchemgeo200503011, doi101016jepsl200902019, doi101016jepsl201209054, doi101016jgca201505026, doi101016s0009254197001599, doi101016s0016703799002045, doi1010292008jb005644, doi10105100046361201116836, doi10106311699114, doi101103physrev77789, doi101103physrevc41889, doi101126science1154339, doi101126science1215507, doi101126science1230492, doi101126scienceaaa0118, doi1011270078042120120020, doi1011300091761319980260995adswat23co2, doi1011302014250502, doi101130b309291, doi101130b310761, doi101130b318901, doi101130g306831"
}

@article{doi101016jgloplacha2020103312,
    author = "Keller, Gerta and Mateo, Paula and Monkenbusch, Johannes and Thibault, Nicolas and Punekar, Jahnavi and Spangenberg, Jorge E. and Abramovich, Sigal and Ashckenazi‐Polivoda, Sarit and Schoene, Blair and Eddy, Michael P. and Samperton, Kyle M. and Khadri, S. and Adatte, Thierry",
    title = "Mercury linked to Deccan Traps volcanism, climate change and the end-Cretaceous mass extinction",
    year = "2020",
    journal = "Global and Planetary Change",
    url = "https://doi.org/10.1016/j.gloplacha.2020.103312",
    doi = "10.1016/j.gloplacha.2020.103312",
    openalex = "W3083573130",
    references = "doi101016jepsl200801015, doi101073pnas2006087117, doi101126scienceaau2422, doi10247508201801"
}

The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.

@article{doi101126scienceaay5055,
    author = "Hull, Pincelli M. and Bornemann, André and Penman, Donald E. and Henehan, Michael J. and Norris, Richard D. and Wilson, Paul A. and Blum, Peter and Alegret, Laia and Batenburg, Sietske J. and Bown, Paul R. and Bralower, Timothy J. and Cournède, C. and Deutsch, A. and Donner, Barbara and Friedrich, Oliver and Jehle, Sofie and Kim, Hojung and Kroon, Dick and Lippert, Peter C. and Loroch, Dominik and Moebius, Iris and Moriya, Kazuyoshi and Peppe, Daniel J. and Ravizza, G. and Röhl, Ursula and Schueth, Jonathan D. and Sepúlveda, Julio and Sexton, Philip F. and Sibert, Elizabeth C and Śliwińska, Kasia K. and Summons, Roger E. and Thomas, Ellen and Westerhold, Thomas and Whiteside, Jessica H. and Yamaguchi, Tatsuhiko and Zachos, James C.",
    title = "On impact and volcanism across the Cretaceous-Paleogene boundary",
    year = "2020",
    journal = "Science",
    abstract = "The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction. We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic outgassing. We found support for major outgassing beginning and ending distinctly before the impact, with only the impact coinciding with mass extinction and biologically amplified carbon cycle change. Our models show that these extinction-related carbon cycle changes would have allowed the ocean to absorb massive amounts of carbon dioxide, thus limiting the global warming otherwise expected from postextinction volcanism.",
    url = "https://doi.org/10.1126/science.aay5055",
    doi = "10.1126/science.aay5055",
    openalex = "W2999541819",
    references = "doi101016jepsl200902019, doi1010292008jb005644, doi101073pnas1319253111, doi101098rspb20181194, doi101126science2825387276, doi101126scienceaaa0118, doi101126scienceaau2422, doi1011300091761319980260995adswat23co2, doi101130b318901"
}