Fungus

More than 13,000 ft of Precambrian and Cambrian sedimentary rocks occur in S.-central Esmeralda County. The succession contains upper Precambrian to Upper Cambrian strata in conformable sequence and appears to be unconformably overlain by the Middle Ordovician Palmetto Formation. The Cambrian rocks are considered to include the oldest Cambrian strata in North America because of the presence of the olenellid trilobite Fallotaspis. Approximately two-thirds of the Precambrian and Lower Cambrian sedimentary rocks are quartzose detrital deposits, similar in thickness and lithologic character to strata of equivalent age in the Inyo Mountains, California. Carbonate rocks dominate the Middle and Upper Cambrian.

@article{doi102475ajs2607530,
    author = "McKee, Edwin H. and Moiola, R. J.",
    title = "Precambrian and Cambrian rocks of south-central Esmeralda County, Nevada",
    year = "1962",
    journal = "American Journal of Science",
    abstract = "More than 13,000 ft of Precambrian and Cambrian sedimentary rocks occur in S.-central Esmeralda County. The succession contains upper Precambrian to Upper Cambrian strata in conformable sequence and appears to be unconformably overlain by the Middle Ordovician Palmetto Formation. The Cambrian rocks are considered to include the oldest Cambrian strata in North America because of the presence of the olenellid trilobite Fallotaspis. Approximately two-thirds of the Precambrian and Lower Cambrian sedimentary rocks are quartzose detrital deposits, similar in thickness and lithologic character to strata of equivalent age in the Inyo Mountains, California. Carbonate rocks dominate the Middle and Upper Cambrian.",
    url = "https://doi.org/10.2475/ajs.260.7.530",
    doi = "10.2475/ajs.260.7.530",
    openalex = "W2326431475"
}

@article{bespalov1965riphean,
    author = "Bespalov, V.F.",
    title = "Riphean and Cambrian of central Asia",
    year = "1965",
    journal = "International Geology Review",
    url = "https://doi.org/10.1080/00206816509474775",
    doi = "10.1080/00206816509474775",
    number = "7",
    openalex = "W1977820629",
    pages = "1237-1251",
    volume = "7"
}

@article{pichova1967microfossils,
    author = "Pichova, N.G.",
    title = "Microfossils of Lower Cambrian and Precambrian deposits in eastern Siberia",
    year = "1967",
    journal = "Review of Palaeobotany and Palynology",
    url = "https://doi.org/10.1016/0034-6667(67)90206-0",
    doi = "10.1016/0034-6667(67)90206-0",
    number = "1-4",
    pages = "31-38",
    volume = "5"
}

@article{sokolov1967allunion,
    author = "Sokolov, B.S.",
    title = "All-Union Symposium on Precambrian and Early Cambrian Paleontology",
    year = "1967",
    journal = "International Geology Review",
    url = "https://doi.org/10.1080/00206816709474507",
    doi = "10.1080/00206816709474507",
    number = "5",
    pages = "743-745",
    volume = "9"
}

Certain worm-like configurations on rocks are recognized as shrinkage-crack infillings. Some genuine Precambrian trace fossils are briefly described. The early Cambrian contains a richer assemblage, including some distinctive and widespread form genera. The study of early trace fossils leads to conclusions not only on facies, but also on the evolution of behaviour and functional morphology in soft-bodied organisms.

@article{doi101111j150239311969tb01258x,
    author = "Glaessner, Martin F.",
    title = "TRACE FOSSILS FROM THE PRECAMBRIAN AND BASAL CAMBRIAN",
    year = "1969",
    journal = "Lethaia",
    abstract = "Certain worm-like configurations on rocks are recognized as shrinkage-crack infillings. Some genuine Precambrian trace fossils are briefly described. The early Cambrian contains a richer assemblage, including some distinctive and widespread form genera. The study of early trace fossils leads to conclusions not only on facies, but also on the evolution of behaviour and functional morphology in soft-bodied organisms.",
    url = "https://doi.org/10.1111/j.1502-3931.1969.tb01258.x",
    doi = "10.1111/j.1502-3931.1969.tb01258.x",
    openalex = "W1975727583",
    references = "doi1010160031018266900113, doi101038scientificamerican036172, doi10108011035896509448903, doi101086626811, doi101111j1469185x1962tb01331x, doi101111j150239311968tb01740x, doi101126science1543750766, doi101130gsab481873, doi101144gsljgs1890046010439, openalexw2170541304, openalexw2586923183"
}

@article{cowie1973stratigraphic,
    author = "Cowie, J.W.",
    title = "Stratigraphic problems of the later precambrian and early cambrian",
    year = "1973",
    journal = "Earth-Science Reviews",
    url = "https://doi.org/10.1016/0012-8252(73)90006-8",
    doi = "10.1016/0012-8252(73)90006-8",
    number = "4",
    openalex = "W2068860450",
    pages = "376-377",
    volume = "9"
}

@article{palmer1975stratigraphic,
    author = "Palmer, A.R.",
    title = "Stratigraphic Problems of the Later Precambrian and Early Cambrian",
    year = "1975",
    journal = "Precambrian Research",
    url = "https://doi.org/10.1016/0301-9268(75)90020-0",
    doi = "10.1016/0301-9268(75)90020-0",
    number = "1",
    openalex = "W272146113",
    pages = "93",
    volume = "2"
}

Twenty-eight species of fifteen genera of Middle Cambrian molluscs are described from tiny phosphatic moulds or silica replicas of the shells. The molluscs were etched from limestones at two sites: one in the earliest Middle Cambrian Coonigan Formation of the Mootwingee area, 130 km northeast of Broken Hill, New South Wales; and another in the middle Middle Cambrian Currant Bush Limestone of the Thorntonia area, 150 km northwest of Mt Isa, Queensland. These unusually diverse collections show that many different kinds of molluscs lived in the tropical Australian seas of the Middle Cambrian and provide new information on the way the molluscan classes Cephalopoda, Gastropoda, Rostro- conchia, and Pelecypoda evolved. In other sections, we discuss the problems of classifying and naming Cambrian molluscs; define a number of terms that can be used to describe shell form (including a new adjective, gyrogastric); reclassify the Class Monoplacophora after incorporating the helcionellacean and bellerophontacean “gastropods”; and outline the early record and history of the Mollusca. New taxa are: the Families Scenellidae (nom. transl. ex Scenellinae Wenz 1938) and Yochelcionellidae; the genera Eotebenna (Yochelcionellidae), Mellopegma (Procarinariidae), and ProtoweneHa (Multifariidae); and the species Helcionella terraustralis, Latouchella accordionata, L. merino, L. penecyrano, Yochelcionella daleki, Y. ostentata, Eotebenna pontifex, E. papilio, Mellopegma georginensis, Stenotheca tepee, S. pojetai, Protowenella flemingi, Pelagiella deltoides, P. corinthiana, and Myonai? queenslandica.

@article{doi10108003115517608619064,
    author = "Runnegar, Bruce and Jell, Peter A.",
    title = "Australian Middle Cambrian molluscs and their bearing on early molluscan evolution",
    year = "1976",
    journal = "Alcheringa An Australasian Journal of Palaeontology",
    abstract = "Twenty-eight species of fifteen genera of Middle Cambrian molluscs are described from tiny phosphatic moulds or silica replicas of the shells. The molluscs were etched from limestones at two sites: one in the earliest Middle Cambrian Coonigan Formation of the Mootwingee area, 130 km northeast of Broken Hill, New South Wales; and another in the middle Middle Cambrian Currant Bush Limestone of the Thorntonia area, 150 km northwest of Mt Isa, Queensland. These unusually diverse collections show that many different kinds of molluscs lived in the tropical Australian seas of the Middle Cambrian and provide new information on the way the molluscan classes Cephalopoda, Gastropoda, Rostro- conchia, and Pelecypoda evolved. In other sections, we discuss the problems of classifying and naming Cambrian molluscs; define a number of terms that can be used to describe shell form (including a new adjective, gyrogastric); reclassify the Class Monoplacophora after incorporating the helcionellacean and bellerophontacean “gastropods”; and outline the early record and history of the Mollusca. New taxa are: the Families Scenellidae (nom. transl. ex Scenellinae Wenz 1938) and Yochelcionellidae; the genera Eotebenna (Yochelcionellidae), Mellopegma (Procarinariidae), and ProtoweneHa (Multifariidae); and the species Helcionella terraustralis, Latouchella accordionata, L. merino, L. penecyrano, Yochelcionella daleki, Y. ostentata, Eotebenna pontifex, E. papilio, Mellopegma georginensis, Stenotheca tepee, S. pojetai, Protowenella flemingi, Pelagiella deltoides, P. corinthiana, and Myonai? queenslandica.",
    url = "https://doi.org/10.1080/03115517608619064",
    doi = "10.1080/03115517608619064",
    openalex = "W2124323345",
    references = "doi101130spe32, doi102475ajs2748833"
}

@article{doi1010160301926878900554,
    author = "Francis, S. and Margulis, L. and Barghoorn, E.",
    title = "On the experimental silicification of microorganisms II. On the time of appearance of eukaryotic organisms in the fossil record",
    year = "1978",
    journal = "Precambrian Research",
    url = "https://www.semanticscholar.org/paper/f8d5b97a1365fb3e184e741a7998ba74dbdd6d72",
    doi = "10.1016/0301-9268(78)90055-4",
    is_oa = "true",
    number = "1",
    pages = "65-100",
    semanticscholar_citation_count = "124",
    semanticscholar_id = "f8d5b97a1365fb3e184e741a7998ba74dbdd6d72",
    volume = "6"
}

Summary The Late Precambrian and Early Cambrian strata in eastern California and Nevada can be divided into 3 facies – the eastern Craton, the White-Inyo, and the Death Valley. These 3 facies supply evidence of 3 trilobite zones – the Fallotaspis, the Nevadella and the Bonnia-Olenellus; the inter-relationships are outlined. Correlations with the Siberian Platform successions are discussed and the Precambrian–Cambrian boundary is tentatively placed within the beds of the upper Reed Dolomite in the White-lnyo Range.

@article{nelson1978late,
    author = "Nelson, C. A.",
    title = "Late Precambrian–Early Cambrian stratigraphic and faunal succession of eastern California and the Precambrian–Cambrian boundary",
    year = "1978",
    journal = "Geological Magazine",
    abstract = "Summary The Late Precambrian and Early Cambrian strata in eastern California and Nevada can be divided into 3 facies – the eastern Craton, the White-Inyo, and the Death Valley. These 3 facies supply evidence of 3 trilobite zones – the Fallotaspis, the Nevadella and the Bonnia-Olenellus; the inter-relationships are outlined. Correlations with the Siberian Platform successions are discussed and the Precambrian–Cambrian boundary is tentatively placed within the beds of the upper Reed Dolomite in the White-lnyo Range.",
    url = "https://doi.org/10.1017/s0016756800041169",
    doi = "10.1017/s0016756800041169",
    number = "2",
    pages = "121-126",
    volume = "115"
}

ON SIGNIFICANCE OF FOSSILS FROM MESOZONAL METAMORPHIC ROCKS OF THE GORY BYSTRZYCKIE AND VICINITIES OF STRONIE ŚLĄSKIE Summary Primitive fossils with features of the Early Paleozoic ones were found in mesozonally alterated gneisses from Wyszki village in the Gory Bystrzyckle Mts, hitherto assigned to the Proterozoic. This locality is stratigraphically lower than that from which Upper Proterozoic flora was recorded (10). Faunal remains of the Early Paleozoic type were also found in mesozonally alterated series of quartzites in the metamorphic area at Goszow in the Gory Bialskie Mts (11). On the basis of these data M. Dumicz (7) presented the following interpretation of geological structure and history of the Klodzko region: (l) Sedimentation continued here from the Precambrian till Orkney phase without breaks, (2) The Early Varisean structural stage is the oldest in the Klodzko region. The author presents evidence for lack of sedimentary continuity (the lack of the Eocambrian and Cambrian). There are also given data presented by other authors (3, 4, 14, 25, 29), evidencing that debris of rocks of the series in which the above mentioned fauna was found at Wyszki and Goszow, occurs in sedimentary rocks of the Eocambrian age in Lutetia, Ordovician age in the Gory Kaczawskie and southern Karkonosze Mts and finally in Early (and possibly Middle) Devonian age from vicinities of Strzelin. It follows that there is no evidence that the metamorphic complex of the Gory Bystrzyckle and Śnieznickie Mts belongs to the same structural stage as the series containing debris of mesozonal rocks. The paper ends with a question given to paleontologists: whether or not this fauna may be interpreted as Proterozoic (as there are no genera on which the stratigraphy of the Paleozoic is based). Some genera of Paleozoic fauna could appear as early as the Proterozoic. According to the present author, the fauna from Wyszki and Goszow strongly enhance search for organic remains in strongly alterated rocks. These finds are, therefore, highly important from the point of view of paleontology but not stratigraphy nor knowledge of geological structure and history of the Klodzko region.

@article{s2bc9e7d708c83b460265408f27d47470e8f7bfe16,
    author = "Oberc, J.",
    title = "Znaczenie skamieniałości w metamorfiku mezozonalnym Gór Bystrzyckich i okolic Stronia Śląskiego",
    year = "1978",
    journal = "Przegląd Geologiczny",
    abstract = "ON SIGNIFICANCE OF FOSSILS FROM MESOZONAL METAMORPHIC ROCKS OF THE GORY BYSTRZYCKIE AND VICINITIES OF STRONIE ŚLĄSKIE Summary Primitive fossils with features of the Early Paleozoic ones were found in mesozonally alterated gneisses from Wyszki village in the Gory Bystrzyckle Mts, hitherto assigned to the Proterozoic. This locality is stratigraphically lower than that from which Upper Proterozoic flora was recorded (10). Faunal remains of the Early Paleozoic type were also found in mesozonally alterated series of quartzites in the metamorphic area at Goszow in the Gory Bialskie Mts (11). On the basis of these data M. Dumicz (7) presented the following interpretation of geological structure and history of the Klodzko region: (l) Sedimentation continued here from the Precambrian till Orkney phase without breaks, (2) The Early Varisean structural stage is the oldest in the Klodzko region. The author presents evidence for lack of sedimentary continuity (the lack of the Eocambrian and Cambrian). There are also given data presented by other authors (3, 4, 14, 25, 29), evidencing that debris of rocks of the series in which the above mentioned fauna was found at Wyszki and Goszow, occurs in sedimentary rocks of the Eocambrian age in Lutetia, Ordovician age in the Gory Kaczawskie and southern Karkonosze Mts and finally in Early (and possibly Middle) Devonian age from vicinities of Strzelin. It follows that there is no evidence that the metamorphic complex of the Gory Bystrzyckle and Śnieznickie Mts belongs to the same structural stage as the series containing debris of mesozonal rocks. The paper ends with a question given to paleontologists: whether or not this fauna may be interpreted as Proterozoic (as there are no genera on which the stratigraphy of the Paleozoic is based). Some genera of Paleozoic fauna could appear as early as the Proterozoic. According to the present author, the fauna from Wyszki and Goszow strongly enhance search for organic remains in strongly alterated rocks. These finds are, therefore, highly important from the point of view of paleontology but not stratigraphy nor knowledge of geological structure and history of the Klodzko region.",
    url = "https://www.semanticscholar.org/paper/bc9e7d708c83b460265408f27d47470e8f7bfe16",
    is_oa = "true",
    openalex = "W2582826234",
    semanticscholar_id = "bc9e7d708c83b460265408f27d47470e8f7bfe16"
}

@misc{german1979finds1,
    author = "German, T. N",
    title = "Finds of Riphean fungus, in Paleontology of the Precambrian and Early Cambrian [in Russian]",
    year = "1979",
    howpublished = "Leningrad, Nauka, p. 129-136",
    note = "talkorigins\_source = {true}; raw\_reference = {German, T. N., 1979, Finds of Riphean fungus, in Paleontology of the Precambrian and Early Cambrian [in Russian]: Leningrad, Nauka, p. 129-136.}"
}

@article{doi101016030192688290050x,
    author = "Brasier, Martin D.",
    title = "Sea-level changes, facies changes and the late Precambrian—Early cambrian evolutionary explosion",
    year = "1982",
    journal = "Precambrian Research",
    url = "https://doi.org/10.1016/0301-9268(82)90050-x",
    doi = "10.1016/0301-9268(82)90050-x",
    openalex = "W2062227426",
    references = "doi102475ajs2748833"
}

@article{openalexw2603635224,
    author = "Crimes, T. P. and Anderson, Michael M.",
    title = "Trace fossils from late Precambrian-Early Cambrian strata of southeastern Newfoundland (Canada); temporal and environmental implications",
    year = "1985",
    journal = "Journal of Paleontology",
    openalex = "W2603635224",
    references = "doi101002gj3350070104, doi101007978140203609529, doi101111j150239311969tb01258x, doi101130009176131973169pswaan20co2, doi101139e83050, doi103931erara11638, hiscott1982tidal, openalexw2344228935, openalexw3116078484, openalexw3171394321, openalexw560220492, openalexw574363047"
}

The Burin Peninsula exhibits an exceptionally thick and essentially continuous succession of marine strata through the Precambrian–Cambrian transition. Fossils are abundant and include trace fossils, small shelly fossils, vendotaenid algae, soft-bodied megafossils, and microfossils. The Burin Peninsula is readily accessible and has long been considered a potential area for a Precambrian–Cambrian boundary stratotype.A continuous section through the upper part of member 1 and all of member 2 of the Chapel Island Formation is exposed at Fortune Head, and this section is herein proposed as a global stratotype for the Precambrian–Cambrian boundary. The boundary horizon is located 2.4 m above the base of member 2 of the Chapel Island Formation. This horizon marks the base of the basal Cambrian Phycodes pedum (ichnofossil) Zone and immediately overlies the top of the Late Precambrian Harlaniella podolica (ichnofossil) Zone. Shelly fossils (sabelliditids) first appear a few metres below the proposed boundary. Soft-bodied megafossils, carbonaceous impressions of vendotaenid algae, and organic-walled microfossils occur both below and above this boundary and enhance global correlation with this section.Fossils of the Rusophycus avalonensis (ichnofossil) Zone first appear midway through member 2 (approximately 135 m above the proposed boundary) and occur commonly throughout the upper part of the Chapel Island Formation and the overlying Random Formation. Calcareous small shelly fossils (?Circotheca sp.) appear near the top of member 2 (approximately 400 m above the proposed boundary), and a more diverse Aldanella attleborensis small shelly fossil assemblage characterizes the uppermost strata of member 3 and all of member 4 of the Chapel Island Formation (approximately 550–650 m above the proposed boundary). The lowest trilobites, representatives of the Callavia broeggeri Zone, first appear more than 1000 m above the proposed Precambrian–Cambrian boundary.

@article{doi101139e87124,
    author = "Narbonne, Guy M. and Myrow, Paul M. and Landing, Ed and Anderson, Michael M.",
    title = "A candidate stratotype for the Precambrian–Cambrian boundary, Fortune Head, Burin Peninsula, southeastern Newfoundland",
    year = "1987",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "The Burin Peninsula exhibits an exceptionally thick and essentially continuous succession of marine strata through the Precambrian–Cambrian transition. Fossils are abundant and include trace fossils, small shelly fossils, vendotaenid algae, soft-bodied megafossils, and microfossils. The Burin Peninsula is readily accessible and has long been considered a potential area for a Precambrian–Cambrian boundary stratotype.A continuous section through the upper part of member 1 and all of member 2 of the Chapel Island Formation is exposed at Fortune Head, and this section is herein proposed as a global stratotype for the Precambrian–Cambrian boundary. The boundary horizon is located 2.4 m above the base of member 2 of the Chapel Island Formation. This horizon marks the base of the basal Cambrian Phycodes pedum (ichnofossil) Zone and immediately overlies the top of the Late Precambrian Harlaniella podolica (ichnofossil) Zone. Shelly fossils (sabelliditids) first appear a few metres below the proposed boundary. Soft-bodied megafossils, carbonaceous impressions of vendotaenid algae, and organic-walled microfossils occur both below and above this boundary and enhance global correlation with this section.Fossils of the Rusophycus avalonensis (ichnofossil) Zone first appear midway through member 2 (approximately 135 m above the proposed boundary) and occur commonly throughout the upper part of the Chapel Island Formation and the overlying Random Formation. Calcareous small shelly fossils (?Circotheca sp.) appear near the top of member 2 (approximately 400 m above the proposed boundary), and a more diverse Aldanella attleborensis small shelly fossil assemblage characterizes the uppermost strata of member 3 and all of member 4 of the Chapel Island Formation (approximately 550–650 m above the proposed boundary). The lowest trilobites, representatives of the Callavia broeggeri Zone, first appear more than 1000 m above the proposed Precambrian–Cambrian boundary.",
    url = "https://doi.org/10.1139/e87-124",
    doi = "10.1139/e87-124",
    openalex = "W2152030224",
    references = "cloud1982the, doi101017s0016756800015922, doi101111j150239311969tb01258x, doi101111j150239311970tb01265x, doi101126science2174562783, doi101130mem158p33, doi101139e78010, doi1023072412725, doi102475ajs2748833, doi105281zenodo16572510, hiscott1982tidal, openalexw2611846784, openalexw3116078484"
}

The latest Proterozoic to Early Cambrian sequences of the Amadeus and Georgina Basins of central Australia have yielded abundant and diverse trace fossils. Those of the Arumbera Sandstone are particularly significant because recent studies of that unit have shown that it is lithologically uniform and spans the Proterozoic-Cambrian boundary with no discernible break. In our studies of this and other units we have been able to distinguish four assemblages of trace fossils forming a succession that we interpret as due to the evolution of bioturbating animals. The lowest strata examined occur immediately above the upper of the two Proterozoic glacial units that are widespread in Australia and comprise the Grant Bluff and Elyuah Formations of the Georgina Basin and the lower Pertatataka Formation (Cyclops Member and below) of the Amadeus Basin. These units lack definite trace fossils, despite having lithofacies comparable with those containing traces higher in the sequence. The probable fossil medusa Bunyerichnus dalgarnoi occurs at this level in the Adelaide Geosyncline, but no trace fossils are known from equivalent strata anywhere in Australia. The lack of trace fossils is significant and we draw attention to it by defining this as Assemblage 0. Assemblage 1 consists only of Planolites ballandus from the lower Elkera Formation of the Georgina Basin. This ‘assemblage’ predates the Ediacara fauna. Assemblage 2 contains trace fossils that in the Adelaide Geosyncline occur with the Ediacara fauna. Vertical burrows are rare in this assemblage although depressions comparable to the lower ends of U-shaped burrows have been recorded from the Adelaide Geosyncline and vertical pit-shaped traces (Hormosiroidea arumbera ichnosp. nov.) are reported here from the Central Mount Stuart Formation, Georgina Basin. Simple horizontal trails and burrows (Planolites sp.), chains of faecal pellets (Neonereites sp.) and arthropod scratch marks (Monomorphichnus sp.) also occur in this assemblage. Assemblage 3 is distinguished by its abundance and diversity of taxa, many of which are large and conspicuous — 35 ichnofossil taxa are recognised. This assemblage is characterised by the presence of deep vertical and complex subhorizontal burrows. It includes the following traces: Curvolithus aequus ichnosp. nov., Curvolithus sp., Didymaulichnus lyelli, D. miettensis, Gordia arcuata, Gordia sp., Gyrochorte sp., Helminthopsis irregularis, Muensteria sp., Nereites sp., Palaeophycus alternatus, P. canalis ichnosp. nov., P. tubularis, Phycodes pedum, Plagiogmus arcuatus, Planolites ballandus, P. beverlyensis, Torrowangea rosei, Treptichnus sp., Diplocraterion parallelum, Diplocraterion sp., Hormosiroidea arumbera ichnosp. nov., Skolithos ramosus ichnosp. nov., S. verticalis, Diplichnites sp., Monomorphichnus bilinearis and M. lineatus. Assemblage 3 occurs in the Uratanna, Parachilna and Lintiss Vale Formations of the Adelaide Geosyncline, Arumbera Sandstone members 3 and 4 in the Amadeus Basin, and the Donkey Creek beds and Mt Baldwin Formation in the Georgina Basin, amongst other units. There is sufficient sedimentological information available to indicate that the succession of assemblages cannot be attributed to environmental changes or to the colonisation of new habitats, and is best interpreted as due to evolution. Very similar successions occur worldwide at this time. Comparisons with all major sections from which trace fossils have been described, including key sections in southern China, the Baltic region and Newfoundland, indicate that Assemblage 3 is Early Cambrian (Tommotian to early Atdabanian) and Assemblages 0–2 are latest Proterozoic (Ediacarian, Vendian).

@article{doi10108003115518908527821,
    author = "Walter, M. R. and Elphinstone, Robyn and Heys, G.R.",
    title = "Proterozoic and Early Cambrian trace fossils from the Amadeus and Georgina Basins, central Australia",
    year = "1989",
    journal = "Alcheringa An Australasian Journal of Palaeontology",
    abstract = "The latest Proterozoic to Early Cambrian sequences of the Amadeus and Georgina Basins of central Australia have yielded abundant and diverse trace fossils. Those of the Arumbera Sandstone are particularly significant because recent studies of that unit have shown that it is lithologically uniform and spans the Proterozoic-Cambrian boundary with no discernible break. In our studies of this and other units we have been able to distinguish four assemblages of trace fossils forming a succession that we interpret as due to the evolution of bioturbating animals. The lowest strata examined occur immediately above the upper of the two Proterozoic glacial units that are widespread in Australia and comprise the Grant Bluff and Elyuah Formations of the Georgina Basin and the lower Pertatataka Formation (Cyclops Member and below) of the Amadeus Basin. These units lack definite trace fossils, despite having lithofacies comparable with those containing traces higher in the sequence. The probable fossil medusa Bunyerichnus dalgarnoi occurs at this level in the Adelaide Geosyncline, but no trace fossils are known from equivalent strata anywhere in Australia. The lack of trace fossils is significant and we draw attention to it by defining this as Assemblage 0. Assemblage 1 consists only of Planolites ballandus from the lower Elkera Formation of the Georgina Basin. This ‘assemblage’ predates the Ediacara fauna. Assemblage 2 contains trace fossils that in the Adelaide Geosyncline occur with the Ediacara fauna. Vertical burrows are rare in this assemblage although depressions comparable to the lower ends of U-shaped burrows have been recorded from the Adelaide Geosyncline and vertical pit-shaped traces (Hormosiroidea arumbera ichnosp. nov.) are reported here from the Central Mount Stuart Formation, Georgina Basin. Simple horizontal trails and burrows (Planolites sp.), chains of faecal pellets (Neonereites sp.) and arthropod scratch marks (Monomorphichnus sp.) also occur in this assemblage. Assemblage 3 is distinguished by its abundance and diversity of taxa, many of which are large and conspicuous — 35 ichnofossil taxa are recognised. This assemblage is characterised by the presence of deep vertical and complex subhorizontal burrows. It includes the following traces: Curvolithus aequus ichnosp. nov., Curvolithus sp., Didymaulichnus lyelli, D. miettensis, Gordia arcuata, Gordia sp., Gyrochorte sp., Helminthopsis irregularis, Muensteria sp., Nereites sp., Palaeophycus alternatus, P. canalis ichnosp. nov., P. tubularis, Phycodes pedum, Plagiogmus arcuatus, Planolites ballandus, P. beverlyensis, Torrowangea rosei, Treptichnus sp., Diplocraterion parallelum, Diplocraterion sp., Hormosiroidea arumbera ichnosp. nov., Skolithos ramosus ichnosp. nov., S. verticalis, Diplichnites sp., Monomorphichnus bilinearis and M. lineatus. Assemblage 3 occurs in the Uratanna, Parachilna and Lintiss Vale Formations of the Adelaide Geosyncline, Arumbera Sandstone members 3 and 4 in the Amadeus Basin, and the Donkey Creek beds and Mt Baldwin Formation in the Georgina Basin, amongst other units. There is sufficient sedimentological information available to indicate that the succession of assemblages cannot be attributed to environmental changes or to the colonisation of new habitats, and is best interpreted as due to evolution. Very similar successions occur worldwide at this time. Comparisons with all major sections from which trace fossils have been described, including key sections in southern China, the Baltic region and Newfoundland, indicate that Assemblage 3 is Early Cambrian (Tommotian to early Atdabanian) and Assemblages 0–2 are latest Proterozoic (Ediacarian, Vendian).",
    url = "https://doi.org/10.1080/03115518908527821",
    doi = "10.1080/03115518908527821",
    openalex = "W1965216306",
    references = "cowie1973stratigraphic, doi1010160301926885900518, doi101038321832a0, doi10108003115519508619270, doi101111j150239311969tb01258x, doi101126science972526482b, doi101139e87124, openalexw2315002392, openalexw2344228935, openalexw2603635224, openalexw589153876"
}

Acritarchs in the sedimentologically continuous, shallow-marine, Upper Vendian - Lower Cambrian subsurface sequence of the Lublin Slope, East European Platform (EEP), Poland are abundant and well-preserved. Forty-five form-species were recovered, and their taxonomic status is revised. Three new form-genera are erected. Asteridium n.gen. and Heliosphaeridium n. gen. include species with solid and hollow processes, respectively, previously referred to Micrhystridium Deflandre. Globosphaeridium n.gen. includes acritarchs with solid processes formerly attributed to Baltisphaeridium Eisenack. The genus Skiagia is emended. Microfossil preservation yields information on the thermal history of the Lublin basin. The acritarch succession in the Lublin Slope forms the basis for a new Lower Cambrian zonation, in ascending order the Asteridium tornaturn - Comasphaeridium velvetum, Skiagia ornata - Fimbriaglomerella membranacea, Heliosphaeridium dissimilare - Skiagia ciliosa, and Volkovia dentifera - Liepaina plana Assemblage-zones. A significant radiation at the upper part of the Włodawa Formation and within the Mazowsze Formation involves taxa of the Asteridiumtornatum - Comasphaeridium velvetum assemblage taken to mark the Pre cambrian-Cambrian boundary. The Kaplonosy IG-1 drillcore is proposed as reference section for the boundary. The Upper Vendian - Lower Cambrian biostratigraphy in Poland is revised. The Sabellidites-Vendotaenia Interval-zone is proposed, the range of the Platysolenites antiquissimus Zone is revised, and the Holmia kjerulfi Assemblage-zone is recognized. The Protolenus zone remains as an informal zone. Parts of the investigated sequence are correlated with the Schmidtiellus mickwitzi Zone elsewhere. The early Cambrian Mobergella Zone and the Klimontovian Stage are rejected. The Precambrian-Cambrian boundary is discussed in light of acritarch evidence from sequences in the East European, Baltoscandian, Siberian, South China and Avalon Platforms. The acritarch zone contemporaneous with the earliest trilobite zone in the Baltoscandian Platform and the EEP embraces part of the Tommotian and Meishucunian strata in Siberia and China. Units underlying the Tommotian in Siberia may be Cambrian. Lower Cambrian rocks of the EEP, the Baltoscandian Platform, and the Scandinavian Caledonides, are correlated on the basis of acritarchs.

@incollection{doi10182618200374742199101,
    author = "Moczydłowska, Małgorzata",
    title = "Acritarch biostratigraphy of the Lower Cambrian and the Precambrian-Cambrian boundary in southeastern Poland",
    year = "1991",
    booktitle = "Fossils and strata",
    abstract = "Acritarchs in the sedimentologically continuous, shallow-marine, Upper Vendian - Lower Cambrian subsurface sequence of the Lublin Slope, East European Platform (EEP), Poland are abundant and well-preserved. Forty-five form-species were recovered, and their taxonomic status is revised. Three new form-genera are erected. Asteridium n.gen. and Heliosphaeridium n. gen. include species with solid and hollow processes, respectively, previously referred to Micrhystridium Deflandre. Globosphaeridium n.gen. includes acritarchs with solid processes formerly attributed to Baltisphaeridium Eisenack. The genus Skiagia is emended. Microfossil preservation yields information on the thermal history of the Lublin basin. The acritarch succession in the Lublin Slope forms the basis for a new Lower Cambrian zonation, in ascending order the Asteridium tornaturn - Comasphaeridium velvetum, Skiagia ornata - Fimbriaglomerella membranacea, Heliosphaeridium dissimilare - Skiagia ciliosa, and Volkovia dentifera - Liepaina plana Assemblage-zones. A significant radiation at the upper part of the Włodawa Formation and within the Mazowsze Formation involves taxa of the Asteridiumtornatum - Comasphaeridium velvetum assemblage taken to mark the Pre cambrian-Cambrian boundary. The Kaplonosy IG-1 drillcore is proposed as reference section for the boundary. The Upper Vendian - Lower Cambrian biostratigraphy in Poland is revised. The Sabellidites-Vendotaenia Interval-zone is proposed, the range of the Platysolenites antiquissimus Zone is revised, and the Holmia kjerulfi Assemblage-zone is recognized. The Protolenus zone remains as an informal zone. Parts of the investigated sequence are correlated with the Schmidtiellus mickwitzi Zone elsewhere. The early Cambrian Mobergella Zone and the Klimontovian Stage are rejected. The Precambrian-Cambrian boundary is discussed in light of acritarch evidence from sequences in the East European, Baltoscandian, Siberian, South China and Avalon Platforms. The acritarch zone contemporaneous with the earliest trilobite zone in the Baltoscandian Platform and the EEP embraces part of the Tommotian and Meishucunian strata in Siberia and China. Units underlying the Tommotian in Siberia may be Cambrian. Lower Cambrian rocks of the EEP, the Baltoscandian Platform, and the Scandinavian Caledonides, are correlated on the basis of acritarchs.",
    url = "https://doi.org/10.18261/8200374742-1991-01",
    doi = "10.18261/8200374742-1991-01",
    openalex = "W4385659530",
    references = "doi1010079783642964466, doi1010160012825272901316, doi1010160012825273900925, doi1010160016703784900899, doi1010160301926887900015, doi1010160301926887900441, doi1010160377839888900023, doi101017s0022336000036465, doi101017s0263593300010051, doi101038321832a0, doi101038333313a0, doi101038scientificamerican0779122, doi101073pnas492158, doi10108011035898209455245, doi101130001676061972831299peboto20co2, doi101139e83050, doi10182618200093301197301, doi1018814epiiugs1985v8i2003, doi1023071484559, doi1023071485622, doi1034194bullgguv1346676, nelson1978late, openalexw2026796374, openalexw2603635224, openalexw2753647789, openalexw353142951, schidlowski1988a, tappan1970geobiologic, vidal1985earths"
}

An explosive episode of biological diversification occurred near the beginning of the Cambrian period. Evolutionary rates in the Cambrian have been difficult to quantify accurately because of a lack of high-precision ages. Currently, uranium-lead zircon geochronology is the most powerful method for dating rocks of Cambrian age. Uranium-lead zircon data from lower Cambrian rocks located in northeast Siberia indicate that the Cambrian period began at approximately 544 million years ago and that its oldest (Manykaian) stage lasted no less than 10 million years. Other data indicate that the Tommotian and Atdabanian stages together lasted only 5 to 10 million years. The resulting compression of Early Cambrian time accentuates the rapidity of both the faunal diversification and subsequent Cambrian turnover.

@article{doi101126science11539488,
    author = "Bowring, Samuel A. and Grotzinger, J. P. and Isachsen, C. E. and Knoll, Andrew H. and Pelechaty, Shane M. and Kolosov, Peter",
    title = "Calibrating Rates of Early Cambrian Evolution",
    year = "1993",
    journal = "Science",
    abstract = "An explosive episode of biological diversification occurred near the beginning of the Cambrian period. Evolutionary rates in the Cambrian have been difficult to quantify accurately because of a lack of high-precision ages. Currently, uranium-lead zircon geochronology is the most powerful method for dating rocks of Cambrian age. Uranium-lead zircon data from lower Cambrian rocks located in northeast Siberia indicate that the Cambrian period began at approximately 544 million years ago and that its oldest (Manykaian) stage lasted no less than 10 million years. Other data indicate that the Tommotian and Atdabanian stages together lasted only 5 to 10 million years. The resulting compression of Early Cambrian time accentuates the rapidity of both the faunal diversification and subsequent Cambrian turnover.",
    url = "https://doi.org/10.1126/science.11539488",
    doi = "10.1126/science.11539488",
    openalex = "W2080974066",
    references = "doi101017s0094837300005649, doi101017s0094837300005972, doi101017s0094837300006539"
}

The presence of calcareous algae of Girvanella Nickolson et Etheridge, Subtifloria Maslov, Renalcis Vologdin is proven in the Upper-Riphean Dashkinskaya Suite of the Yenisei Ridge, Rechkinskaya, Turukhanskaya, Burovaya suites on the Turukhan Uplift, and Chenchinskaya Suite of the Patomskoe Upland in East Siberia. Now the conclusion is made that algae got the posibility for calcifying and preserving in sediments already in the Upper Riphean rather than near the Precambrian — Cambrian boundary as was considered before. Thus, taking into account finds of calcareous algae of Girvanella, Subtifloria, and Renalcis the earlier conclusion that their hosted deposits are older than Late Vendian – Early Cambrian seems to be erroneous.

@article{doi102113rgg199334860,
    author = "Terleev, A.",
    title = "CALCAREOUS ALGAE ( CALCIOBIONTA ) IN THE RIPHEAN DEPOSITS OF EAST SIBERIA",
    year = "1993",
    journal = "Russian Geology and Geophysics",
    abstract = "The presence of calcareous algae of Girvanella Nickolson et Etheridge, Subtifloria Maslov, Renalcis Vologdin is proven in the Upper-Riphean Dashkinskaya Suite of the Yenisei Ridge, Rechkinskaya, Turukhanskaya, Burovaya suites on the Turukhan Uplift, and Chenchinskaya Suite of the Patomskoe Upland in East Siberia. Now the conclusion is made that algae got the posibility for calcifying and preserving in sediments already in the Upper Riphean rather than near the Precambrian — Cambrian boundary as was considered before. Thus, taking into account finds of calcareous algae of Girvanella, Subtifloria, and Renalcis the earlier conclusion that their hosted deposits are older than Late Vendian – Early Cambrian seems to be erroneous.",
    url = "https://www.semanticscholar.org/paper/a2a3bd19408015f41317df2899e793b3a55b3b6f",
    doi = "10.2113/rgg.1993.34.8.60",
    is_oa = "true",
    number = "8",
    pages = "60-67",
    semanticscholar_id = "a2a3bd19408015f41317df2899e793b3a55b3b6f",
    volume = "34"
}

Abstract Articulated halkieriids of Halkieria evangelista sp. nov. are described from the Sirius Passet fauna in the Lower Cambrian Buen Formation of Peary Land, North Greenland. Three zones of sclerites are recognizable: obliquely inclined rows of dorsal palmates, quincuncially inserted lateral cultrates and imbricated bundles of ventro-lateral siculates. In addition there is a prominent shell at both ends, each with radial ornamentation. Both sclerites and shells were probably calcareous, but increase in body size led to insertion of additional sclerites but marginal accretion of the shells. The ventral sole was soft and, in life, presumably muscular. Recognizable features of internal anatomy include a gut trace and possible musculature, inferred from imprints on the interior of the anterior shell. Halkieriids are closely related to the Middle Cambrian Wixaxia, best known from the Burgess Shale: this clade appears to have played an important role in early protostome evolution. From an animal fairly closely related to Wixaxia arose the polychaete annelids; the bundles of siculate sclerites prefigure the neurochaetae whereas the dorsal notochaetae derive from the palmates. Wixaxia appears to have a relic shell and a similar structure in the sternaspid polychaetes may be an evolutionary remnant. The primitive state in extant polychaetes is best expressed in groups such as chrysopetalids, aphroditaceans and amphinomids. The homology between polychaete chaetae and the mantle setae of brachiopods is one line of evidence to suggest that the latter phylum arose from a juvenile halkieriid in which the posterior shell was first in juxtaposition to the anterior and rotated beneath it to provide the bivalved condition of an ancestral brachiopod. H. evangelista sp. nov. has shells which resemble those of a brachiopod; in particular the posterior one. From predecessors of the halkieriids known as siphogonuchitids it is possible that both chitons (polyplacophorans) and conchiferan molluscs arose. The hypothesis of halkieriids and their relatives having a key role in annelid—brachiopod—mollusc evolution is in accord with some earlier proposals and recent evidence from molecular biology. It casts doubt, however, on a number of favoured concepts including the primitive annelid being oligochaetoid and a burrower, the brachiopods being deuterostomes and the coelom being an archaic feature of metazoans. Rather, the annelid coelom arose as a functional consequence of the transition from a creeping halkieriid to a polychaete with stepping parapodial locomotion.

@article{doi101098rstb19950029,
    author = "Morris, Simon Conway and Peel, John S.",
    title = "Articulated halkieriids from the Lower Cambrian of North Greenland and their role in early protostome evolution",
    year = "1995",
    journal = "Philosophical Transactions of the Royal Society B Biological Sciences",
    abstract = "Abstract Articulated halkieriids of Halkieria evangelista sp. nov. are described from the Sirius Passet fauna in the Lower Cambrian Buen Formation of Peary Land, North Greenland. Three zones of sclerites are recognizable: obliquely inclined rows of dorsal palmates, quincuncially inserted lateral cultrates and imbricated bundles of ventro-lateral siculates. In addition there is a prominent shell at both ends, each with radial ornamentation. Both sclerites and shells were probably calcareous, but increase in body size led to insertion of additional sclerites but marginal accretion of the shells. The ventral sole was soft and, in life, presumably muscular. Recognizable features of internal anatomy include a gut trace and possible musculature, inferred from imprints on the interior of the anterior shell. Halkieriids are closely related to the Middle Cambrian Wixaxia, best known from the Burgess Shale: this clade appears to have played an important role in early protostome evolution. From an animal fairly closely related to Wixaxia arose the polychaete annelids; the bundles of siculate sclerites prefigure the neurochaetae whereas the dorsal notochaetae derive from the palmates. Wixaxia appears to have a relic shell and a similar structure in the sternaspid polychaetes may be an evolutionary remnant. The primitive state in extant polychaetes is best expressed in groups such as chrysopetalids, aphroditaceans and amphinomids. The homology between polychaete chaetae and the mantle setae of brachiopods is one line of evidence to suggest that the latter phylum arose from a juvenile halkieriid in which the posterior shell was first in juxtaposition to the anterior and rotated beneath it to provide the bivalved condition of an ancestral brachiopod. H. evangelista sp. nov. has shells which resemble those of a brachiopod; in particular the posterior one. From predecessors of the halkieriids known as siphogonuchitids it is possible that both chitons (polyplacophorans) and conchiferan molluscs arose. The hypothesis of halkieriids and their relatives having a key role in annelid—brachiopod—mollusc evolution is in accord with some earlier proposals and recent evidence from molecular biology. It casts doubt, however, on a number of favoured concepts including the primitive annelid being oligochaetoid and a burrower, the brachiopods being deuterostomes and the coelom being an archaic feature of metazoans. Rather, the annelid coelom arose as a functional consequence of the transition from a creeping halkieriid to a polychaete with stepping parapodial locomotion.",
    url = "https://doi.org/10.1098/rstb.1995.0029",
    doi = "10.1098/rstb.1995.0029",
    openalex = "W2001586405",
    references = "doi101007978148992427812, doi1010160301926885900518, doi101017s0022336000037057, doi101038326181a0, doi101038345802a0, doi101038361219a0, doi101098rstb19790006, doi101098rstb19850005, doi101111j143904691975tb00509x, doi101111j146363951991tb00312x, doi101111j146364091991tb00303x, doi101111j150239311969tb01258x, doi101111j150239311993tb01502x, doi101126science2224620163, doi101126science2464928339, doi101126science3277277, doi101144gsjgs14940631, doi101146annureves10110179001551, doi105962bhltitle8596, morris1979the, morris1987a, openalexw2138270429, openalexw2302261279, openalexw2754161204, openalexw589153876"
}

Ediacara-type fossils are rare in the southwestern United States, and Cambrian occurrences of soft-bodied Ediacaran-type fossils are extremely rare. We report both discoidal and frondlike fossils comparable to Ediacaran taxa from the western edge of the Great Basin. We describe one specimen of a discoidal fossil, referred to the form species?Tirasiana disciformis, from the upper member of the Lower Cambrian Wood Canyon Formation from the Salt Spring Hills, California. Two fragmentary specimens of frond-like soft-bodied fossils are described from the middle member of the Lower Cambrian Poleta Formation in the White Mountains, California, and the upper member of the Wood Canyon Formation in the southern Kelso Mountains, California. On the basis of similarities with fossils from the lower member of the Wood Canyon Formation and from the Spitzkopf Member of the Urusis Formation of Namibia, these specimens are interpreted as cf. Swartpuntia. All fossils were collected from strata containing diagnostic Early Cambrian body and trace fossils, and thus add to previous reports of complex Ediacaran forms in Cambrian marine environments. In this region, Swartpuntia persists through several hundred meters of section, spanning at least two trilobite zones.

@article{doi1016660022336020000740731ecetff20co2,
    author = "Hagadorn, James W. and Fedo, Christopher M. and Waggoner, Ben",
    title = "EARLY CAMBRIAN EDIACARAN-TYPE FOSSILS FROM CALIFORNIA",
    year = "2000",
    journal = "Journal of Paleontology",
    abstract = "Ediacara-type fossils are rare in the southwestern United States, and Cambrian occurrences of soft-bodied Ediacaran-type fossils are extremely rare. We report both discoidal and frondlike fossils comparable to Ediacaran taxa from the western edge of the Great Basin. We describe one specimen of a discoidal fossil, referred to the form species?Tirasiana disciformis, from the upper member of the Lower Cambrian Wood Canyon Formation from the Salt Spring Hills, California. Two fragmentary specimens of frond-like soft-bodied fossils are described from the middle member of the Lower Cambrian Poleta Formation in the White Mountains, California, and the upper member of the Wood Canyon Formation in the southern Kelso Mountains, California. On the basis of similarities with fossils from the lower member of the Wood Canyon Formation and from the Spitzkopf Member of the Urusis Formation of Namibia, these specimens are interpreted as cf. Swartpuntia. All fossils were collected from strata containing diagnostic Early Cambrian body and trace fossils, and thus add to previous reports of complex Ediacaran forms in Cambrian marine environments. In this region, Swartpuntia persists through several hundred meters of section, spanning at least two trilobite zones.",
    url = "https://doi.org/10.1666/0022-3360(2000)074<0731:ecetff>2.0.co;2",
    doi = "10.1666/0022-3360(2000)074<0731:ecetff>2.0.co;2",
    openalex = "W2180142056",
    references = "doi101126science1403568820, doi101126science1543750766"
}

@misc{s29b964a24bf7f480376d9baafc6defa626fa593ba,
    author = "Myrow, P. and Pope, M. and Goodge, J. and Fischer, W. and Palmer, A. R.",
    title = "tectonism in the central Transantarctic Mountains , Antarctica Depositional history of pre-Devonian strata and timing of Ross orogenic",
    year = "2002",
    url = "https://www.semanticscholar.org/paper/9b964a24bf7f480376d9baafc6defa626fa593ba",
    is_oa = "true",
    semanticscholar_id = "9b964a24bf7f480376d9baafc6defa626fa593ba"
}

@article{doi101017s0022336000043535,
    author = "Forey, P.",
    title = "Jeffrey S. Levington 2001. Genetics, Paleontology and Macroevolution , second edition. Cambridge University Press, Cambridge, 617 p. (paperback, ISBN 0 521 00550 7, hardback ISBN 0 521 80317 9)",
    year = "2003",
    journal = "Journal of Paleontology",
    url = "https://www.semanticscholar.org/paper/797c5ae366c44d234246b85fd48121e677eedb08",
    doi = "10.1017/S0022336000043535",
    is_oa = "true",
    number = "1",
    pages = "199-200",
    semanticscholar_id = "797c5ae366c44d234246b85fd48121e677eedb08",
    volume = "77"
}

Biostratigraphic, carbon isotope, and U-Pb zircon geochronological data from the Ara Group of Oman indicate an abrupt last appearance of Cloudina and Namacalathus coincident with a large-magnitude, but short-lived negative excursion in the carbon isotope composition of seawater that is globally coincident with the Precambrian-Cambrian boundary. U-Pb zircon age data from an intercalated ash bed directly define this negative excursion to be at 542.0 ± 0.3 Ma, consistent with previous age constraints from Siberia and Namibia. Combined with the global biostratigraphic record, these new data strengthen hypotheses invoking mass extinction within terminal Proterozoic ecosystems at or near the Precambrian-Cambrian boundary.

@article{doi1011300091761320030310431eocana20co2,
    author = "Amthor, Joachim E. and Grotzinger, J. P. and Schröder, Stefan and Bowring, Samuel A. and Ramezani, Jahandar and Martin, Mark W. and Matter, Albert",
    title = "Extinction of Cloudina and Namacalathus at the Precambrian-Cambrian boundary in Oman",
    year = "2003",
    journal = "Geology",
    abstract = "Biostratigraphic, carbon isotope, and U-Pb zircon geochronological data from the Ara Group of Oman indicate an abrupt last appearance of Cloudina and Namacalathus coincident with a large-magnitude, but short-lived negative excursion in the carbon isotope composition of seawater that is globally coincident with the Precambrian-Cambrian boundary. U-Pb zircon age data from an intercalated ash bed directly define this negative excursion to be at 542.0 ± 0.3 Ma, consistent with previous age constraints from Siberia and Namibia. Combined with the global biostratigraphic record, these new data strengthen hypotheses invoking mass extinction within terminal Proterozoic ecosystems at or near the Precambrian-Cambrian boundary.",
    url = "https://doi.org/10.1130/0091-7613(2003)031<0431:eocana>2.0.co;2",
    doi = "10.1130/0091-7613(2003)031<0431:eocana>2.0.co;2",
    openalex = "W2075619059",
    references = "doi101016s0016703798000593, doi101017s001675680100509x, doi101073pnas092150999, doi101126science11539488, doi101126science2705236598, doi101126science28454232129, doi10113000917613200028143ctfftt20co2, doi1011300091761320010290995oaatpc20co2, doi1016660094837320000260334cmitsr20co2, doi102110jsr681223"
}

The Precambrian-Cambrian boundary presents an interesting stratigraphic conundrum: the trace fossil used to mark and correlate the base of the Cambrian, Treptichnus pedum, is restricted to siliciclastic facies, whereas biomineralized fossils and chemostratigraphic signals are most commonly obtained from carbonate-dominated sections. Thus, it is difficult to correlate directly between many of the Precambrian-Cambrian boundary sections, and to assess details of the timing of evolutionary events that transpired during this interval of time. Thick sections in the White-Inyo region of eastern California and western Nevada, USA, contain mixed siliciclastic-carbonate lithofacies, and therefore promote correlation between these classic, well-studied lithologic end-members. An integrated stratigraphic approach was applied to the White-Inyo succession, combining lithologic, paleontologic, and chemostratigraphic data, in order to address the temporal framework within the basin, and to facilitate worldwide correlation of the boundary. Results from the southern Great Basin demonstrate that the negative δ13C excursion that is ubiquitous in carbonate-dominated successions containing small shelly fossils occurs within stratigraphic uncertainty of the first occurrence of T. pedum. This global geochemical marker thus provides a link with the primary biostratigraphic indicator for the Precambrian-Cambrian boundary.

@article{doi102110sedred200314,
    author = "Corsetti, Frank A. and Hagadorn, James W.",
    title = "The Precambrian-Cambrian Transition in the Southern Great Basin, USA",
    year = "2003",
    journal = "The Sedimentary Record",
    abstract = "The Precambrian-Cambrian boundary presents an interesting stratigraphic conundrum: the trace fossil used to mark and correlate the base of the Cambrian, Treptichnus pedum, is restricted to siliciclastic facies, whereas biomineralized fossils and chemostratigraphic signals are most commonly obtained from carbonate-dominated sections. Thus, it is difficult to correlate directly between many of the Precambrian-Cambrian boundary sections, and to assess details of the timing of evolutionary events that transpired during this interval of time. Thick sections in the White-Inyo region of eastern California and western Nevada, USA, contain mixed siliciclastic-carbonate lithofacies, and therefore promote correlation between these classic, well-studied lithologic end-members. An integrated stratigraphic approach was applied to the White-Inyo succession, combining lithologic, paleontologic, and chemostratigraphic data, in order to address the temporal framework within the basin, and to facilitate worldwide correlation of the boundary. Results from the southern Great Basin demonstrate that the negative δ13C excursion that is ubiquitous in carbonate-dominated successions containing small shelly fossils occurs within stratigraphic uncertainty of the first occurrence of T. pedum. This global geochemical marker thus provides a link with the primary biostratigraphic indicator for the Precambrian-Cambrian boundary.",
    url = "https://doi.org/10.2110/sedred.2003.1.4",
    doi = "10.2110/sedred.2003.1.4",
    openalex = "W2181560488",
    references = "doi1010160012825285900017, doi1010160301926894000708, doi101073pnas94136600, doi101126science11539488, doi101126science1543750766, doi101126science2705236598, doi101126science28454232129, doi10113000167606196273139lcswmc20co2, doi101306d42695672b2611d78648000102c1865d, doi101306m26490c5, doi103133pp620, nelson1978late, openalexw1533729466, openalexw1594946638"
}

Ichnofossils Arenicolites, Didymaulichnus, Gordia, Helminthopsis, Monomorphichnus, Phycodes pedum and Planolites A, B and C are described from the Late Precambrian -Middle Cambrian Pele La Group exposed in the Tang chu - Wachi La sector of the Bhutan Himalaya. The Precambrian-Cambrian boundary in this section is tentatively placed below the Phycodes pedum level, in the middle part of the Maneting Formation. The volcanics of the Singhi Formation, occurring at the base of the Pele La Group represent an important Neoproterozoic event.

@article{tangri2003late,
    author = "Tangri, S. K. and Bhargava, O. N. and Pande, A. C.",
    title = "Late Precambrian - Early Cambrian Trace Fossils from Tethyan Himalaya, Bhutan and their Bearing on the Precambrian-Cambrian Boundary",
    year = "2003",
    journal = "Journal of the Geological Society of India",
    abstract = "Ichnofossils Arenicolites, Didymaulichnus, Gordia, Helminthopsis, Monomorphichnus, Phycodes pedum and Planolites A, B and C are described from the Late Precambrian -Middle Cambrian Pele La Group exposed in the Tang chu - Wachi La sector of the Bhutan Himalaya. The Precambrian-Cambrian boundary in this section is tentatively placed below the Phycodes pedum level, in the middle part of the Maneting Formation. The volcanics of the Singhi Formation, occurring at the base of the Pele La Group represent an important Neoproterozoic event.",
    url = "https://doi.org/10.17491/jgsi/2003/620605",
    doi = "10.17491/jgsi/2003/620605",
    number = "6",
    openalex = "W2601914186",
    pages = "706-716",
    volume = "62",
    references = "doi101002gj3350070104, doi1010160031018279901123, doi101111j150239311969tb01258x, doi101126science282538680, doi1017491jgsi1982230405, doi1017491jgsi1983240403, doi1017491jgsi1988320304, doi1017491jgsi1998510507, doi10182618200376656199701, doi102110pec85350021"
}

We present a δ 13 C record from the Anti-Atlas mountains of Morocco and place it in the context of a detailed regional tectonostratigraphy. We place the litho- and chemostratigraphic record in a temporal framework using precision U–Pb zircon geochronology of ashes interbedded with the same carbonate units that provide δ 13 C data. The variations in δ 13 C of carbonate occur on a wide range of time scales, suggesting that different mechanisms are involved, including non-steady state release of isotopically depleted carbon reservoirs on short (<100 000 years) time scales and changes in nutrient recycling and organic carbon burial on longer (≥1 Ma) time scales. Through a correlation with more fossiliferous, albeit condensed, sections in Siberia, we examine the pattern of cyclic δ 13 C variation in the context of the reappearance and diversification of skeletonized metazoa during the Early Cambrian.

@article{doi101139e05062,
    author = "Maloof, Adam C. and Schrag, Daniel P. and Crowley, James L. and Bowring, Samuel A.",
    title = "An expanded record of Early Cambrian carbon cycling from the Anti-Atlas Margin, Morocco",
    year = "2005",
    journal = "Canadian Journal of Earth Sciences",
    abstract = "We present a δ 13 C record from the Anti-Atlas mountains of Morocco and place it in the context of a detailed regional tectonostratigraphy. We place the litho- and chemostratigraphic record in a temporal framework using precision U–Pb zircon geochronology of ashes interbedded with the same carbonate units that provide δ 13 C data. The variations in δ 13 C of carbonate occur on a wide range of time scales, suggesting that different mechanisms are involved, including non-steady state release of isotopically depleted carbon reservoirs on short (<100 000 years) time scales and changes in nutrient recycling and organic carbon burial on longer (≥1 Ma) time scales. Through a correlation with more fossiliferous, albeit condensed, sections in Siberia, we examine the pattern of cyclic δ 13 C variation in the context of the reappearance and diversification of skeletonized metazoa during the Early Cambrian.",
    url = "https://doi.org/10.1139/e05-062",
    doi = "10.1139/e05-062",
    openalex = "W2141398750",
    references = "doi1010160016703773902135, doi101016001670378290165x, doi101016030442039500008f, doi101016jpalwor200610016, doi101016s0009254199000819, doi10102995pa02087, doi10103822941, doi101086628978, doi101103physrevc41889, doi10113000917613200028299ptdvus20co2, doi101139p66090, doi102475ajs2837641, openalexw1552913007"
}

Trilobites from the Lower Cambrian succession at Angorichina in the eastern Flinders Ranges, South Australia, are described. Silicified material from the Mernmerna Formation reveals the presence of a new assemblage from the Pararaia bunyerooensis Zone, including the eponymous species, Yorkella aff. australis, Eoredlichia sp., Redlichia sp., and the new species Wutingaspis euryoptilos and Yunnanocephalus macromelos. Trilobites of the Pararaia bunyerooensis Zone show a strong affinity with those from the Yu'anshan Member of the Heilinpu Formation in Chengjiang and Jinning Counties, Yunnan Province, southwest China. The Pararaia bunyerooensis Zone is correlated with the Yunnanocephalus Assemblage subzone (upper Eoredlichia–Wutingaspis Zone) of the Chiungchussuan (=Qiongzhusian) Stage of China. Additional trilobites from Angorichina include Elicicola calva from the Wilkawillina Limestone, Estaingia occipitospina (Jell) new combination from the Oraparinna Shale, and Redlichia guizhouensis Zhou from the Wirrealpa Limestone. Australian Early Cambrian trilobite biozonation is reviewed, with discussion of distinct assemblages within the Pararaia janeae Zone that have the potential for zonal subdivision, and evidence to support the placement of the northern Australian Ordian/Early Templetonian Stage within the late Early Cambrian.A possible paedomorphic lineage between Pararaia bunyerooensis and P. janeae is proposed. Adult specimens of P. janeae retain juvenile characteristics of the progenitor P. bunyerooensis. Retardation in onset of maturity in P. janeae resulted in the attainment of a larger adult size than in P. bunyerooensis, indicating the former species evolved via neoteny.

@article{doi10166600223360200781116ectfaf20co2,
    author = "Paterson, John R. and Brock, Glenn A.",
    title = "EARLY CAMBRIAN TRILOBITES FROM ANGORICHINA, FLINDERS RANGES, SOUTH AUSTRALIA, WITH A NEW ASSEMBLAGE FROM THE PARARAIA BUNYEROOENSIS ZONE",
    year = "2007",
    journal = "Journal of Paleontology",
    abstract = "Trilobites from the Lower Cambrian succession at Angorichina in the eastern Flinders Ranges, South Australia, are described. Silicified material from the Mernmerna Formation reveals the presence of a new assemblage from the Pararaia bunyerooensis Zone, including the eponymous species, Yorkella aff. australis, Eoredlichia sp., Redlichia sp., and the new species Wutingaspis euryoptilos and Yunnanocephalus macromelos. Trilobites of the Pararaia bunyerooensis Zone show a strong affinity with those from the Yu'anshan Member of the Heilinpu Formation in Chengjiang and Jinning Counties, Yunnan Province, southwest China. The Pararaia bunyerooensis Zone is correlated with the Yunnanocephalus Assemblage subzone (upper Eoredlichia–Wutingaspis Zone) of the Chiungchussuan (=Qiongzhusian) Stage of China. Additional trilobites from Angorichina include Elicicola calva from the Wilkawillina Limestone, Estaingia occipitospina (Jell) new combination from the Oraparinna Shale, and Redlichia guizhouensis Zhou from the Wirrealpa Limestone. Australian Early Cambrian trilobite biozonation is reviewed, with discussion of distinct assemblages within the Pararaia janeae Zone that have the potential for zonal subdivision, and evidence to support the placement of the northern Australian Ordian/Early Templetonian Stage within the late Early Cambrian.A possible paedomorphic lineage between Pararaia bunyerooensis and P. janeae is proposed. Adult specimens of P. janeae retain juvenile characteristics of the progenitor P. bunyerooensis. Retardation in onset of maturity in P. janeae resulted in the attainment of a larger adult size than in P. bunyerooensis, indicating the former species evolved via neoteny.",
    url = "https://doi.org/10.1666/0022-3360(2007)81[116:ectfaf]2.0.co;2",
    doi = "10.1666/0022-3360(2007)81[116:ectfaf]2.0.co;2",
    openalex = "W2186726138",
    references = "doi104095100784"
}

Abstract Data on the first appearances of major animal groups with mineralized skeletons on the Siberian Platform and worldwide are revised and summarized herein with references to an improved carbon isotope stratigraphy and radiometric dating in order to reconstruct the Cambrian radiation (popularly known as the ‘Cambrian explosion’) with a higher precision and provide a basis for the definition of Cambrian Stages 2 to 4. The Lophotrochozoa and, probably, Chaetognatha were first among protostomians to achieve biomineralization during the Terreneuvian Epoch, mainly the Fortunian Age. Fast evolutionary radiation within the Lophotrochozoa was followed by radiation of the sclerotized and biomineralized Ecdysozoa during Stage 3. The first mineralized skeletons of the Deuterostomia, represented by echinoderms, appeared in the middle of Cambrian Stage 3. The fossil record of sponges and cnidarians suggests that they acquired biomineralized skeletons in the late Neoproterozoic, but diversification of both definite sponges and cnidarians was in parallel to that of bilaterians. The distribution of calcium carbonate skeletal mineralogies from the upper Ediacaran to lower Cambrian reflects fluctuations in the global ocean chemistry and shows that the Cambrian radiation occurred mainly during a time of aragonite and high-magnesium calcite seas.

@article{doi101017s0016756811000720,
    author = "Kouchinsky, Artem and Bengtson, Stefan and Runnegar, Bruce and Skovsted, Christian B. and Steiner, Michael and Vendrasco, Michael J.",
    title = "Chronology of early Cambrian biomineralization",
    year = "2011",
    journal = "Geological Magazine",
    abstract = "Abstract Data on the first appearances of major animal groups with mineralized skeletons on the Siberian Platform and worldwide are revised and summarized herein with references to an improved carbon isotope stratigraphy and radiometric dating in order to reconstruct the Cambrian radiation (popularly known as the ‘Cambrian explosion’) with a higher precision and provide a basis for the definition of Cambrian Stages 2 to 4. The Lophotrochozoa and, probably, Chaetognatha were first among protostomians to achieve biomineralization during the Terreneuvian Epoch, mainly the Fortunian Age. Fast evolutionary radiation within the Lophotrochozoa was followed by radiation of the sclerotized and biomineralized Ecdysozoa during Stage 3. The first mineralized skeletons of the Deuterostomia, represented by echinoderms, appeared in the middle of Cambrian Stage 3. The fossil record of sponges and cnidarians suggests that they acquired biomineralized skeletons in the late Neoproterozoic, but diversification of both definite sponges and cnidarians was in parallel to that of bilaterians. The distribution of calcium carbonate skeletal mineralogies from the upper Ediacaran to lower Cambrian reflects fluctuations in the global ocean chemistry and shows that the Cambrian radiation occurred mainly during a time of aragonite and high-magnesium calcite seas.",
    url = "https://doi.org/10.1017/s0016756811000720",
    doi = "10.1017/s0016756811000720",
    openalex = "W2127465210",
    references = "bengtson1976the, brasier1987microfossils, doi101002jemt10217, doi101002jezb21090, doi10100797814615074751, doi10100797814899242787, doi101016c20090644421, doi101016jpalaeo200401022, doi101016jpalaeo200703046, doi101016jpalaeo200902013, doi101016jpalwor200610014, doi101016s0031018298001096, doi101017s0022336000024963, doi101017s0022336000034879, doi101017s0022336000036465, doi101038326181a0, doi101038nature06614, doi101038nature07673, doi101093icb431166, doi101098rspb20063761, doi101111j109636421995tb00110x, doi101111j150239311975tb01311x, doi101111j150239311999tb00547x, doi101126science1107765, doi101126science2705236598, doi101127zdgg1111959434, doi101130g25094a1, doi101146annurevearth33092203122519, doi101666100651, doi10182618200067378198301, doi101826182003741571989, doi104202app20090058, doi105860choice304422, doi105860choice465038, doi105962bhltitle66379, morris1987a, openalexw2473761340, openalexw2598873191, openalexw3127114020, openalexw587905045, tiwari1999organicwalled"
}

Diverse bilaterian clades emerged apparently within a few million years during the early Cambrian, and various environmental, developmental, and ecological causes have been proposed to explain this abrupt appearance. A compilation of the patterns of fossil and molecular diversification, comparative developmental data, and information on ecological feeding strategies indicate that the major animal clades diverged many tens of millions of years before their first appearance in the fossil record, demonstrating a macroevolutionary lag between the establishment of their developmental toolkits during the Cryogenian [(850 to 635 million years ago (Ma)], and the later ecological success of metazoans during the Ediacaran (635 to 541 Ma) and Cambrian (541 to 488 Ma) periods. We argue that this diversification involved new forms of developmental regulation, as well as innovations in networks of ecological interaction within the context of permissive environmental circumstances.

@article{doi101126science1206375,
    author = "Erwin, Douglas H. and Laflamme, Marc and Tweedt, Sarah M. and Sperling, Erik A. and Pisani, Davide and Peterson, Kevin J.",
    title = "The Cambrian Conundrum: Early Divergence and Later Ecological Success in the Early History of Animals",
    year = "2011",
    journal = "Science",
    abstract = "Diverse bilaterian clades emerged apparently within a few million years during the early Cambrian, and various environmental, developmental, and ecological causes have been proposed to explain this abrupt appearance. A compilation of the patterns of fossil and molecular diversification, comparative developmental data, and information on ecological feeding strategies indicate that the major animal clades diverged many tens of millions of years before their first appearance in the fossil record, demonstrating a macroevolutionary lag between the establishment of their developmental toolkits during the Cryogenian [(850 to 635 million years ago (Ma)], and the later ecological success of metazoans during the Ediacaran (635 to 541 Ma) and Cambrian (541 to 488 Ma) periods. We argue that this diversification involved new forms of developmental regulation, as well as innovations in networks of ecological interaction within the context of permissive environmental circumstances.",
    url = "https://doi.org/10.1126/science.1206375",
    doi = "10.1126/science.1206375",
    openalex = "W2111414198",
    references = "doi101016jasd200910002, doi101016jpalwor200610016, doi101017s000632310000548x, doi101017s0016756800007603, doi101017s0016756811000720, doi101017s0022336000036465, doi101017s009483730001681x, doi101017s1089332600001133, doi10103835318, doi101038nature04894, doi101038nature05345, doi101038nature06811, doi101038nature09038, doi101038ngeo934, doi101073pnas0902322106, doi10108000241160410004764, doi10108003115510508619300, doi101093bioinformaticsbtg180, doi101093bioinformaticsbtp368, doi101093molbevmsl150, doi101093molbevmsm193, doi101098rstb20090038, doi101111j150239311989tb01332x, doi101111j150239311990tb01373x, doi101111j155856461987tb02459x, doi101126science1113832, doi101126science1135013, doi101126science1139158, doi101126science28454232129, doi1011300091761319940220179pcbgsr23co2, doi1011300091761320030310431eocana20co2, doi101144gsjgs14940607, doi101146annurevearth33092203122519, doi101146annurevecolsys35112202130124, doi101371journalpbio0040088, doi101371journalpbio1000602, doi101371journalpone0001121, doi101371journalpone0009586, doi10166609102r1, doi101826182003769311997, doi1018900012965819970781946paneoo20co2, doi1023072409086, doi10247510200701, doi104202app20090058, doi105962bhltitle82303"
}

A current paradigm accepts the presence of weakly biomineralized animals only, barely above a low metazoan grade of organization in the terminal Neoproterozoic (Ediacaran), and a later, early Cambrian burst of well skeletonized animals. Here we report new assemblages of primarily calcareous shelly fossils from upper Ediacaran (553-542 Ma) carbonates of Spain and Russia (Siberian Platform). The problematic organism Cloudina is found in the Yudoma Group of the southeastern Siberian Platform and different skeletal taxa have been discovered in the terminal Neoproterozoic of several provinces of Spain. New data on the morphology and microstructure of Ediacaran skeletal fossils Cloudina and Namacalathus indicate that the Neoproterozoic skeletal organisms were already reasonably advanced. In total, at least 15 skeletal metazoan genera are recorded worldwide within this interval. This number is comparable with that known for the basal early Cambrian. These data reveal that the terminal Neoproterozoic skeletal bloom was a real precursor of the Cambrian radiation. Cloudina, the oldest animal with a mineralised skeleton on the Siberian Platform, characterises the uppermost Ediacaran strata of the Ust'-Yudoma Formation. While in Siberia Cloudina co-occurs with small skeletal fossils of Cambrian aspect, in Spain Cloudina-bearing carbonates and other Ediacaran skeletal fossils alternate with strata containing rich trace fossil assemblages. These finds treated together provide a possibility to correlate transitional Neoproterozoic-lower Cambrian strata around the world. Such a correlation concurs with available isotope and radiometric data and indicates that typical Ediacaran shelly fossils have not crossed the Precambrian-Cambrian boundary.

@article{doi104202app20100074,
    author = "Zhuravlev, Andrey Yu. and Liñán, Eladio and Vintaned, José Antonio Gámez and Debrenne, Françoise and Fedorov, Aleksandr B.",
    title = "New Finds of Skeletal Fossils in the Terminal Neoproterozoic of the Siberian Platform and Spain",
    year = "2011",
    journal = "Acta Palaeontologica Polonica",
    abstract = "A current paradigm accepts the presence of weakly biomineralized animals only, barely above a low metazoan grade of organization in the terminal Neoproterozoic (Ediacaran), and a later, early Cambrian burst of well skeletonized animals. Here we report new assemblages of primarily calcareous shelly fossils from upper Ediacaran (553-542 Ma) carbonates of Spain and Russia (Siberian Platform). The problematic organism Cloudina is found in the Yudoma Group of the southeastern Siberian Platform and different skeletal taxa have been discovered in the terminal Neoproterozoic of several provinces of Spain. New data on the morphology and microstructure of Ediacaran skeletal fossils Cloudina and Namacalathus indicate that the Neoproterozoic skeletal organisms were already reasonably advanced. In total, at least 15 skeletal metazoan genera are recorded worldwide within this interval. This number is comparable with that known for the basal early Cambrian. These data reveal that the terminal Neoproterozoic skeletal bloom was a real precursor of the Cambrian radiation. Cloudina, the oldest animal with a mineralised skeleton on the Siberian Platform, characterises the uppermost Ediacaran strata of the Ust'-Yudoma Formation. While in Siberia Cloudina co-occurs with small skeletal fossils of Cambrian aspect, in Spain Cloudina-bearing carbonates and other Ediacaran skeletal fossils alternate with strata containing rich trace fossil assemblages. These finds treated together provide a possibility to correlate transitional Neoproterozoic-lower Cambrian strata around the world. Such a correlation concurs with available isotope and radiometric data and indicates that typical Ediacaran shelly fossils have not crossed the Precambrian-Cambrian boundary.",
    url = "https://doi.org/10.4202/app.2010.0074",
    doi = "10.4202/app.2010.0074",
    openalex = "W2021151202",
    references = "doi102110sedred200314"
}

@article{doi101134s1028334x12080028,
    author = "Buchko, I. V. and Sorokin, A. A. and Kudryashov, N.",
    title = "Age and tectonic position of the early paleozoic Malyi Khingan Terrane in the Eastern part of the Central Asian fold belt",
    year = "2012",
    journal = "Doklady Earth Sciences",
    url = "https://www.semanticscholar.org/paper/678b18ea45ddef523f5967895359f00f6f0e5e7f",
    doi = "10.1134/S1028334X12080028",
    is_oa = "true",
    number = "2",
    pages = "929-933",
    semanticscholar_citation_count = "11",
    semanticscholar_id = "678b18ea45ddef523f5967895359f00f6f0e5e7f",
    volume = "445"
}

One of the greatest challenges in science lies in disentangling causality in complex, coupled systems. This is illustrated no better than in the dynamic interplay between the Earth and life. The early evolution and diversification of animals occurred within a backdrop of global change, yet reconstructing the potential role of the environment in this evolutionary transition is challenging. In the 200 million years from the end-Cryogenian to the Ordovician, enigmatic Ediacaran fauna explored body plans, animals diversified and began to biomineralize, forever changing the ocean's chemical cycles, and the biological community in shallow marine ecosystems transitioned from a microbial one to an animal one. In the following dissertation, a multi-faceted approach combining macro- and micro-scale analyses is presented that draws on the sedimentology, geochemistry and paleontology of the rocks that span this transition to better constrain the potential environmental changes during this interval. In Chapter 1, the potential of clumped isotope thermometry in deep time is explored by assessing the importance of burial and diagenesis on the thermometer. Eocene- to Precambrian-aged carbonates from the Sultanate of Oman were analyzed from current burial depths of 350-5850 meters. Two end-member styles of diagenesis independent of burial depth were observed. Chapters 2, 3 and 4 explore the fallibility of the Ediacaran carbon isotope record and aspects of the sedimentology and geochemistry of the rocks preserving the largest negative carbon isotope excursion on record---the Shuram Excursion. Chapter 2 documents the importance of temperature, fluid composition and mineralogy on the delta 18-O min record and interrogates the bulk trace metal signal. Chapter 3 explores the spatial variability in delta 13-C recorded in the transgressive Johnnie Oolite and finds a north-to-south trend recording the onset of the excursion. Chapter 4 investigates the nature of seafloor precipitation during this excursion and more broadly. We document the potential importance of microbial respiratory reactions on the carbonate chemistry of the sediment-water interface through time. Chapter 5 investigates the latest Precambrian sedimentary record in carbonates from the Sultanate of Oman, including how delta 13-C and delta 34-S CAS vary across depositional and depth gradients. A new model for the correlation of the Buah and Ara formations across Oman is presented. Isotopic results indicate delta 13-C varies with relative eustatic change and delta 34-S CAS may vary in absolute magnitude across Oman. Chapter 6 investigates the secular rise in delta 18-Omin in the early Paleozoic by using clumped isotope geochemistry on calcitic and phosphatic fossils from the Cambrian and Ordovician. Results do not indicate extreme delta 18-O seawater depletion and instead suggest warmer equatorial temperatures across the early Paleozoic.

@article{doi107907kfjx7s28,
    author = "Bergmann, K.",
    title = "Constraints on the Carbon Cycle and Climate During the Early Evolution of Animals",
    year = "2013",
    abstract = "One of the greatest challenges in science lies in disentangling causality in complex, coupled systems. This is illustrated no better than in the dynamic interplay between the Earth and life. The early evolution and diversification of animals occurred within a backdrop of global change, yet reconstructing the potential role of the environment in this evolutionary transition is challenging. In the 200 million years from the end-Cryogenian to the Ordovician, enigmatic Ediacaran fauna explored body plans, animals diversified and began to biomineralize, forever changing the ocean's chemical cycles, and the biological community in shallow marine ecosystems transitioned from a microbial one to an animal one. In the following dissertation, a multi-faceted approach combining macro- and micro-scale analyses is presented that draws on the sedimentology, geochemistry and paleontology of the rocks that span this transition to better constrain the potential environmental changes during this interval. In Chapter 1, the potential of clumped isotope thermometry in deep time is explored by assessing the importance of burial and diagenesis on the thermometer. Eocene- to Precambrian-aged carbonates from the Sultanate of Oman were analyzed from current burial depths of 350-5850 meters. Two end-member styles of diagenesis independent of burial depth were observed. Chapters 2, 3 and 4 explore the fallibility of the Ediacaran carbon isotope record and aspects of the sedimentology and geochemistry of the rocks preserving the largest negative carbon isotope excursion on record---the Shuram Excursion. Chapter 2 documents the importance of temperature, fluid composition and mineralogy on the delta 18-O min record and interrogates the bulk trace metal signal. Chapter 3 explores the spatial variability in delta 13-C recorded in the transgressive Johnnie Oolite and finds a north-to-south trend recording the onset of the excursion. Chapter 4 investigates the nature of seafloor precipitation during this excursion and more broadly. We document the potential importance of microbial respiratory reactions on the carbonate chemistry of the sediment-water interface through time. Chapter 5 investigates the latest Precambrian sedimentary record in carbonates from the Sultanate of Oman, including how delta 13-C and delta 34-S CAS vary across depositional and depth gradients. A new model for the correlation of the Buah and Ara formations across Oman is presented. Isotopic results indicate delta 13-C varies with relative eustatic change and delta 34-S CAS may vary in absolute magnitude across Oman. Chapter 6 investigates the secular rise in delta 18-Omin in the early Paleozoic by using clumped isotope geochemistry on calcitic and phosphatic fossils from the Cambrian and Ordovician. Results do not indicate extreme delta 18-O seawater depletion and instead suggest warmer equatorial temperatures across the early Paleozoic.",
    url = "https://www.semanticscholar.org/paper/4449bfb4c0daa9c1b4dc1a66756835f483fa1bfb",
    doi = "10.7907/KFJX-7S28.",
    is_oa = "true",
    openalex = "W2122373698",
    semanticscholar_citation_count = "20",
    semanticscholar_id = "4449bfb4c0daa9c1b4dc1a66756835f483fa1bfb"
}

Ediacaran and early Cambrian strata in NW Canada contain abundant trace fossils that record the progressive development of complex behavior in early animal evolution. Five feeding groups can be recognized: microbial grazing, deposit-feeding, deposit-feeding/predatory, filter-feeding/predatory, and arthropod tracks and trails. The lower Blueflower Formation (ca. 560–550 Ma) contains abundant burrows that completely cover bedding surfaces with small (∼1 mm diameter) cylindrical burrows that were strictly restricted to microbial bedding surfaces and exhibited only primitive and inconsistent avoidance strategies. The upper Blueflower contains three-dimensional avoidance burrows and rare filter-feeding or possibly predatory burrows, suggesting increased behavioral responses in food gathering that marked the beginning of the agronomic revolution in substrate utilization. Cambrian strata of the Ingta Formation contain systematically meandering burrows and more diverse feeding strategies, including the onset of treptichnid probing burrows that may reflect predation. These observations imply that Ediacaran burrowers were largely characterized by crude, two-dimensional avoidance meanders that represented simple behavioral responses of individual burrowers to sensory information, and that the subsequent development of more diverse and complex feeding patterns with genetically programmed search pathways occurred during the earliest stages of the Cambrian explosion. These observations further imply that changes occurred in both the food source and substrate during the ecological transition from Proterozoic matgrounds to Phanerozoic mixgrounds.

@article{doi10166613066,
    author = "Carbone, Calla and Narbonne, Guy M.",
    title = "When Life Got Smart: The Evolution of Behavioral Complexity Through the Ediacaran and Early Cambrian of NW Canada",
    year = "2014",
    journal = "Journal of Paleontology",
    abstract = "Ediacaran and early Cambrian strata in NW Canada contain abundant trace fossils that record the progressive development of complex behavior in early animal evolution. Five feeding groups can be recognized: microbial grazing, deposit-feeding, deposit-feeding/predatory, filter-feeding/predatory, and arthropod tracks and trails. The lower Blueflower Formation (ca. 560–550 Ma) contains abundant burrows that completely cover bedding surfaces with small (∼1 mm diameter) cylindrical burrows that were strictly restricted to microbial bedding surfaces and exhibited only primitive and inconsistent avoidance strategies. The upper Blueflower contains three-dimensional avoidance burrows and rare filter-feeding or possibly predatory burrows, suggesting increased behavioral responses in food gathering that marked the beginning of the agronomic revolution in substrate utilization. Cambrian strata of the Ingta Formation contain systematically meandering burrows and more diverse feeding strategies, including the onset of treptichnid probing burrows that may reflect predation. These observations imply that Ediacaran burrowers were largely characterized by crude, two-dimensional avoidance meanders that represented simple behavioral responses of individual burrowers to sensory information, and that the subsequent development of more diverse and complex feeding patterns with genetically programmed search pathways occurred during the earliest stages of the Cambrian explosion. These observations further imply that changes occurred in both the food source and substrate during the ecological transition from Proterozoic matgrounds to Phanerozoic mixgrounds.",
    url = "https://doi.org/10.1666/13-066",
    doi = "10.1666/13-066",
    openalex = "W2127681197",
    references = "doi101016jearscirev201303008, doi101038nature10689, doi101130g308291, morris1980shelly"
}

@article{s2ff0e7239d2abf8e96e8b4bb0cd77eb7bd8659ba0,
    author = "Daragan-Suschova, L. A. and Petrov, O. and Daragan-Suschov, Yu. I.",
    title = "On the Issue of Barents-Kara Region Basement Age, Russian Arctic*",
    year = "2014",
    url = "https://www.semanticscholar.org/paper/ff0e7239d2abf8e96e8b4bb0cd77eb7bd8659ba0",
    is_oa = "true",
    semanticscholar_id = "ff0e7239d2abf8e96e8b4bb0cd77eb7bd8659ba0"
}

Abstract Well-preserved microfossils occur in abundance through more than 1000 m of lower Mesoproterozoic siliciclastic rocks composing the Roper Group, Northern Territory, Australia. The Roper assemblage includes 34 taxa, five interpreted unambiguously as eukaryotes, nine as possible eukaryotes (including Blastanosphaira kokkoda new genus and new species, a budding spheromorph with thin chagrinate walls), eight as possible or probable cyanobacteria, and 12 incertae sedis. Taxonomic richness is highest in inshore facies, and populations interpreted as unambiguous or probable eukaryotes occur most abundantly in coastal and proximal shelf shales. Phylogenetic placement within the Eukarya is difficult, and molecular clock estimates suggest that preserved microfossils may belong, in part or in toto, to stem group eukaryotes (forms that diverged before the last common ancestor of extant eukaryotes, or LECA) or stem lineages within major clades of the eukaryotic crown group (after LECA). Despite this, Roper fossils provide direct or inferential evidence for many basic features of eukaryotic biology, including a dynamic cytoskeleton and membrane system that enabled cells to change shape, life cycles that include resting cysts coated by decay-resistant biopolymers, reproduction by budding and binary division, osmotrophy, and simple multicellularity. The diversity, environmental range, and ecological importance of eukaryotes, however, were lower than in later Neoproterozoic and Phanerozoic ecosystems.

@article{doi101017jpa2016124,
    author = "Javaux, Emmanuelle and Knoll, Andrew H.",
    title = "Micropaleontology of the lower Mesoproterozoic Roper Group, Australia, and implications for early eukaryotic evolution",
    year = "2016",
    journal = "Journal of Paleontology",
    abstract = "Abstract Well-preserved microfossils occur in abundance through more than 1000 m of lower Mesoproterozoic siliciclastic rocks composing the Roper Group, Northern Territory, Australia. The Roper assemblage includes 34 taxa, five interpreted unambiguously as eukaryotes, nine as possible eukaryotes (including Blastanosphaira kokkoda new genus and new species, a budding spheromorph with thin chagrinate walls), eight as possible or probable cyanobacteria, and 12 incertae sedis. Taxonomic richness is highest in inshore facies, and populations interpreted as unambiguous or probable eukaryotes occur most abundantly in coastal and proximal shelf shales. Phylogenetic placement within the Eukarya is difficult, and molecular clock estimates suggest that preserved microfossils may belong, in part or in toto, to stem group eukaryotes (forms that diverged before the last common ancestor of extant eukaryotes, or LECA) or stem lineages within major clades of the eukaryotic crown group (after LECA). Despite this, Roper fossils provide direct or inferential evidence for many basic features of eukaryotic biology, including a dynamic cytoskeleton and membrane system that enabled cells to change shape, life cycles that include resting cysts coated by decay-resistant biopolymers, reproduction by budding and binary division, osmotrophy, and simple multicellularity. The diversity, environmental range, and ecological importance of eukaryotes, however, were lower than in later Neoproterozoic and Phanerozoic ecosystems.",
    url = "https://doi.org/10.1017/jpa.2016.124",
    doi = "10.1017/jpa.2016.124",
    openalex = "W2245961040",
    references = "doi101017cbo9780511601064, doi101073pnas1110633108, doi10108003115517808527785, doi101093molbevmsh075, doi1010990022128711111, doi101126science1061457, doi101126science1069651, doi101126science1221748, doi101128mmbr0502411, doi101146annurevearth271313, doi1016660094837320000260386bpngns20co2, doi102110palo2013p13005r"
}

@article{doi101017jpa2017100,
    author = "Foote, M.",
    title = "Presentation of the 2014 Charles Schuchert Award of the Paleontological Society to Shanan E. Peters",
    year = "2017",
    journal = "Journal of Paleontology",
    url = "https://www.cambridge.org/core/services/aop-cambridge-core/content/view/2A16A8DBE222A1E4C57DB1B864AB8A14/S0022336017001007a.pdf/div-class-title-presentation-of-the-2014-charles-schuchert-award-of-the-paleontological-society-to-shanan-e-peters-div.pdf",
    doi = "10.1017/JPA.2017.100",
    is_oa = "true",
    number = "6",
    pages = "1326-1327",
    semanticscholar_id = "dd067aa6ba04fb4e6cfb5004d326f3da8cbf0e3a",
    volume = "91"
}

Euarthropoda is one of the best-preserved fossil animal groups and has been the most diverse animal phylum for over 500 million years. Fossil Konservat-Lagerstätten, such as Burgess Shale-type deposits (BSTs), show the evolution of the euarthropod stem lineage during the Cambrian from 518 million years ago (Ma). The stem lineage includes nonbiomineralized groups, such as Radiodonta (e.g., Anomalocaris) that provide insight into the step-by-step construction of euarthropod morphology, including the exoskeleton, biramous limbs, segmentation, and cephalic structures. Trilobites are crown group euarthropods that appear in the fossil record at 521 Ma, before the stem lineage fossils, implying a ghost lineage that needs to be constrained. These constraints come from the trace fossil record, which show the first evidence for total group Euarthropoda (e.g., Cruziana, Rusophycus) at around 537 Ma. A deep Precambrian root to the euarthropod evolutionary lineage is disproven by a comparison of Ediacaran and Cambrian lagerstätten. BSTs from the latest Ediacaran Period (e.g., Miaohe biota, 550 Ma) are abundantly fossiliferous with algae but completely lack animals, which are also missing from other Ediacaran windows, such as phosphate deposits (e.g., Doushantuo, 560 Ma). This constrains the appearance of the euarthropod stem lineage to no older than 550 Ma. While each of the major types of fossil evidence (BSTs, trace fossils, and biomineralized preservation) have their limitations and are incomplete in different ways, when taken together they allow a coherent picture to emerge of the origin and subsequent radiation of total group Euarthropoda during the Cambrian.

@article{doi101073pnas1719962115,
    author = "Daley, Allison C. and Antcliffe, Jonathan B. and Drage, Harriet B. and Pates, Stephen",
    title = "Early fossil record of Euarthropoda and the Cambrian Explosion",
    year = "2018",
    journal = "Proceedings of the National Academy of Sciences",
    abstract = "Euarthropoda is one of the best-preserved fossil animal groups and has been the most diverse animal phylum for over 500 million years. Fossil Konservat-Lagerstätten, such as Burgess Shale-type deposits (BSTs), show the evolution of the euarthropod stem lineage during the Cambrian from 518 million years ago (Ma). The stem lineage includes nonbiomineralized groups, such as Radiodonta (e.g., Anomalocaris) that provide insight into the step-by-step construction of euarthropod morphology, including the exoskeleton, biramous limbs, segmentation, and cephalic structures. Trilobites are crown group euarthropods that appear in the fossil record at 521 Ma, before the stem lineage fossils, implying a ghost lineage that needs to be constrained. These constraints come from the trace fossil record, which show the first evidence for total group Euarthropoda (e.g., Cruziana, Rusophycus) at around 537 Ma. A deep Precambrian root to the euarthropod evolutionary lineage is disproven by a comparison of Ediacaran and Cambrian lagerstätten. BSTs from the latest Ediacaran Period (e.g., Miaohe biota, 550 Ma) are abundantly fossiliferous with algae but completely lack animals, which are also missing from other Ediacaran windows, such as phosphate deposits (e.g., Doushantuo, 560 Ma). This constrains the appearance of the euarthropod stem lineage to no older than 550 Ma. While each of the major types of fossil evidence (BSTs, trace fossils, and biomineralized preservation) have their limitations and are incomplete in different ways, when taken together they allow a coherent picture to emerge of the origin and subsequent radiation of total group Euarthropoda during the Cambrian.",
    url = "https://doi.org/10.1073/pnas.1719962115",
    doi = "10.1073/pnas.1719962115",
    openalex = "W2803773655",
    references = "doi101016b9780444594259000196, doi101016jcub201509066, doi101016jearscirev201303008, doi101016jearscirev201606008, doi101016jearscirev201707017, doi101016jpalwor200610005, doi101017s000632310000548x, doi101017s1089332600002837, doi101038376053a0, doi101038nature07673, doi101038nature10689, doi101038nature11874, doi101038nature12520, doi101038nature13414, doi101038nature14256, doi101038ncomms3485, doi101073pnas1111784109, doi101098rstb19750033, doi101098rstb20140313, doi101111brv12168, doi101111j10960031201200413x, doi101126science1107765, doi101126science1169514, doi101126science1206375, doi101126science2745287568, doi101144gsjgs14940607, doi101146annurevearth33092203122519, doi101186s1286201710887, doi101666061301, doi10166612056"
}

Burgess Shale-type fossil Lagerstätten provide the best evidence for deciphering the biotic patterns and magnitude of the Cambrian explosion. Here, we report a Lagerstätte from South China, the Qingjiang biota (~518 million years old), which is dominated by soft-bodied taxa from a distal shelf setting. The Qingjiang biota is distinguished by pristine carbonaceous preservation of labile organic features, a very high proportion of new taxa (~53%), and preliminary taxonomic diversity that suggests it could rival the Chengjiang and Burgess Shale biotas. Defining aspects of the Qingjiang biota include a high abundance of cnidarians, including both medusoid and polypoid forms; new taxa resembling extant kinorhynchs; and abundant larval or juvenile forms. This distinctive composition holds promise for providing insights into the evolution of Cambrian ecosystems across environmental gradients.

@article{doi101126scienceaau8800,
    author = "Fu, Dongjing and Tong, Guanghui and Dai, Tao and Liu, Wei and Yang, Yuning and Zhang, Yuan and Cui, Linhao and Li, Luoyang and Yun, Hao and Wu, Yu and Sun, Ao and Liu, Cong and Pei, Wenrui and Gaines, Robert R. and Zhang, Xingliang",
    title = "The Qingjiang biota—A Burgess Shale–type fossil Lagerstätte from the early Cambrian of South China",
    year = "2019",
    journal = "Science",
    abstract = "Burgess Shale-type fossil Lagerstätten provide the best evidence for deciphering the biotic patterns and magnitude of the Cambrian explosion. Here, we report a Lagerstätte from South China, the Qingjiang biota (\textasciitilde 518 million years old), which is dominated by soft-bodied taxa from a distal shelf setting. The Qingjiang biota is distinguished by pristine carbonaceous preservation of labile organic features, a very high proportion of new taxa (\textasciitilde 53\%), and preliminary taxonomic diversity that suggests it could rival the Chengjiang and Burgess Shale biotas. Defining aspects of the Qingjiang biota include a high abundance of cnidarians, including both medusoid and polypoid forms; new taxa resembling extant kinorhynchs; and abundant larval or juvenile forms. This distinctive composition holds promise for providing insights into the evolution of Cambrian ecosystems across environmental gradients.",
    url = "https://doi.org/10.1126/science.aau8800",
    doi = "10.1126/science.aau8800",
    openalex = "W2923733494",
    references = "doi1010029781118896372, doi101007s114340140419y, doi1010160016703795000382, doi101016b9780444594259000196, doi101016jearscirev201707017, doi101016jpalwor201510001, doi101017s108933260000276x, doi101038nature11874, doi101038ncomms4210, doi101073pnas1111784109, doi101073pnas1719962115, doi101111j14754983200700656x, doi101130g24961a1, doi101144jgs1582211, doi101144jgs2015083, doi10166612056, doi102110palo2009p09004r"
}

@article{sharma2021precambrian,
    author = "Sharma, Mukund and Singh, Veeru Kant and Pandey, Santosh K. and Ansari, Arif H. and Shukla, Yogmaya and Ahmad, Shamim and Kumar, Yogesh and Singh, Divya",
    title = "Precambrian and early Cambrian palaeobiology of India: Quo Vadis",
    year = "2021",
    journal = "Proceedings of the Indian National Science Academy",
    url = "https://doi.org/10.1007/s43538-021-00029-2",
    doi = "10.1007/s43538-021-00029-2",
    number = "2",
    openalex = "W3173571870",
    pages = "199-233",
    volume = "87",
    references = "doi101038384055a0, doi101038nature04764, doi101038nature06811, doi101038nature13068, doi101038nmicrobiol201648, doi101038s4146701600096, doi101073pnas1110633108, doi101073pnas87124576, doi101126science1206375, doi1023071485834"
}

@book{crossref2022precambrian,
    title = "Precambrian Paleontology",
    year = "2022",
    booktitle = "Frontiers Research Topics",
    url = "https://doi.org/10.3389/978-2-83250-118-4",
    doi = "10.3389/978-2-83250-118-4"
}

The great oxidation event (GOE), ~2.4 billion years ago, caused fundamental changes to the chemistry of Earth's surface environments. However, the effect of these changes on the biosphere is unknown, due to a worldwide lack of well-preserved fossils from this time. Here, we investigate exceptionally preserved, large spherical aggregate (SA) microfossils permineralised in chert from the c. 2.4 Ga Turee Creek Group in Western Australia. Field and petrographic observations, Raman spectroscopic mapping, and in situ carbon isotopic analyses uncover insights into the morphology, habitat, reproduction and metabolism of this unusual form, whose distinctive, SA morphology has no known counterpart in the fossil record. Comparative analysis with microfossils from before the GOE reveals the large SA microfossils represent a step-up in cellular organisation. Morphological comparison to extant micro-organisms indicates the SAs have more in common with coenobial algae than coccoidal bacteria, emphasising the complexity of this microfossil form. The remarkable preservation here provides a unique window into the biosphere, revealing an increase in the complexity of life coinciding with the GOE.

@article{doi101111gbi12576,
    author = "Barlow, Erica V. and House, Christopher H. and Liu, Ming‐Chang and Wetherington, Maxwell and Kranendonk, Martin J. Van",
    title = "Distinctive microfossil supports early Paleoproterozoic rise in complex cellular organisation",
    year = "2023",
    journal = "Geobiology",
    abstract = "The great oxidation event (GOE), \textasciitilde 2.4 billion years ago, caused fundamental changes to the chemistry of Earth's surface environments. However, the effect of these changes on the biosphere is unknown, due to a worldwide lack of well-preserved fossils from this time. Here, we investigate exceptionally preserved, large spherical aggregate (SA) microfossils permineralised in chert from the c. 2.4 Ga Turee Creek Group in Western Australia. Field and petrographic observations, Raman spectroscopic mapping, and in situ carbon isotopic analyses uncover insights into the morphology, habitat, reproduction and metabolism of this unusual form, whose distinctive, SA morphology has no known counterpart in the fossil record. Comparative analysis with microfossils from before the GOE reveals the large SA microfossils represent a step-up in cellular organisation. Morphological comparison to extant micro-organisms indicates the SAs have more in common with coenobial algae than coccoidal bacteria, emphasising the complexity of this microfossil form. The remarkable preservation here provides a unique window into the biosphere, revealing an increase in the complexity of life coinciding with the GOE.",
    url = "https://doi.org/10.1111/gbi.12576",
    doi = "10.1111/gbi.12576",
    openalex = "W4387420905",
    references = "doi101016jtim200507008, doi101016s0009254199000832, doi101038nrmicro2365, doi101073pnas1110633108, doi101126science1473658563, doi101126science2605108640, doi101146annurevarplant56032604144052, doi1023072260522, doi1023072879, doi105860choice403394"
}