DSDP

@misc{ladd1967drilling3,
    author = "Ladd, H. S. and Gross, M. G",
    title = "Drilling on Midway Atoll, Hawaii",
    year = "1967",
    howpublished = "Science, v. 156, p. 1088-1094",
    note = "talkorigins\_source = {true}; raw\_reference = {Ladd, H. S., and Gross, M. G., 1967, Drilling on Midway Atoll, Hawaii: Science, v. 156, p. 1088-1094.}"
}

This paper summarizes the results of the three previous papers in this series, which have shown the presence of a pattern of magnetic anomalies, bilaterally symmetric about the crest of the ridge in the Pacific, Atlantic, and Indian oceans. By assuming that the pattern is caused by a sequence of normally and reversely magnetized blocks that have been produced by sea floor spreading at the axes of the ridges, it is shown that the sequences of blocks correspond to the same geomagnetic time scale. An attempt is made to determine the absolute ages of this time scale using palcomagnetic and paleontological data. The pattern of opening of the oceans is discussed and the implications on continental drift are considered. This pattern is in good agreement with continental drift, in particular with the history of the break up of Gondwanaland.

@article{doi101029jb073i006p02119,
    author = "Heirtzler, J. R. and Dickson, G. O. and Herron, E. M. and Pitman, Walter C. and Pichon, Xavier Le",
    title = "Marine magnetic anomalies, geomagnetic field reversals, and motions of the ocean floor and continents",
    year = "1968",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "This paper summarizes the results of the three previous papers in this series, which have shown the presence of a pattern of magnetic anomalies, bilaterally symmetric about the crest of the ridge in the Pacific, Atlantic, and Indian oceans. By assuming that the pattern is caused by a sequence of normally and reversely magnetized blocks that have been produced by sea floor spreading at the axes of the ridges, it is shown that the sequences of blocks correspond to the same geomagnetic time scale. An attempt is made to determine the absolute ages of this time scale using palcomagnetic and paleontological data. The pattern of opening of the oceans is discussed and the implications on continental drift are considered. This pattern is in good agreement with continental drift, in particular with the history of the break up of Gondwanaland.",
    url = "https://doi.org/10.1029/jb073i006p02119",
    doi = "10.1029/jb073i006p02119",
    openalex = "W2027477351",
    references = "doi101029jb073i006p01959, doi101029jb073i012p03661, doi101029jz072i008p02131, doi101038190854a0, doi101038199947a0, doi101038207343a0, doi101126science15437531164, doi101126science15437551405, doi101130petrologic1962599, openalexw2978227140, sykes1967mechanism"
}

@article{lepinchon1968seafloor5,
    author = "Le Pinchon, X",
    title = "Sea-floor spreading and continental drift",
    year = "1968",
    journal = "Journal of Geophysical Research, v. 73, p. 3661-3697",
    note = "talkorigins\_source = {true}; raw\_reference = {Le Pinchon, X., 1968, Sea-floor spreading and continental drift: Journal of Geophysical Research, v. 73, p. 3661-3697.}"
}

@misc{noble1968deepocean6,
    author = "Noble, C. S. and Naughton, J. J",
    title = "Deep-ocean basalts",
    year = "1968",
    howpublished = "Inert gas and uncertainties in age dating: Science, v. 162, p. 265-267",
    note = "talkorigins\_source = {true}; raw\_reference = {Noble, C. S., and Naughton, J. J., 1968, Deep-ocean basalts: Inert gas and uncertainties in age dating: Science, v. 162, p. 265-267.}"
}

@article{doi1010160025322771900533,
    author = "von Huene, Roland",
    title = "Initial reports of the deep sea drilling project",
    year = "1971",
    journal = "Marine Geology",
    url = "https://doi.org/10.1016/0025-3227(71)90053-3",
    doi = "10.1016/0025-3227(71)90053-3",
    openalex = "W2318152314"
}

@misc{worzel1973initial9,
    author = "Worzel, J. L. et al",
    title = "Initial Reports of the Deep Sea Drilling Program",
    year = "1973",
    howpublished = "Washington, D.C., U.S. Government Printing Office, v. 10",
    note = "talkorigins\_source = {true}; raw\_reference = {Worzel, J. L. et al., 1973, Initial Reports of the Deep Sea Drilling Program: Washington, D.C., U.S. Government Printing Office, v. 10.}"
}

Basalts cored on legs 2 and 3 of the Deep-Sea Drilling Project (DSDP) range in sea floor spreading age from 18 to 67×106 yr. Although many of the basalts are highly altered, fresh glass is usually present. Except for site 2–10 the fresh glasses are petrographically and geochemically similar to mid-Atlantic ridge (MAR) axial basalts. There are no systematic compositional differences as a function of distance from the MAR axis. Two sites contain basalts with olivine (Fo90) phenocrysts, high Mg/Mg + ΣFe, high Ni and Cr abundances, and very low large ion lithophile (LIL) element abundances. These basalts are the best candidates for primary magma recovered from the sea floor; fractional crystallization of such basalt may yield the more evolved basalts typical of the MAR. More fractionated basalts with clinopyroxene phenocrysts occur at twp other sites, but they retain low LIL element abundances. Site 2-10 contains titaniferous augite and is relatively enriched in LIL elements. It is unlikely that this basalt was derived by fractional crystallization from LIL element depleted tholeiites; instead, the site 2-10 basalt requires a different mantle source. These results imply that the upper Atlantic Ocean basement is dominantly LIL element depleted tholeiite.

@article{doi101029jb079i035p05507,
    author = "Frey, Frederick A. and Bryan, W. B. and Thompson, Geoffrey",
    title = "Atlantic ocean floor: Geochemistry and petrology of basalts from legs 2 and 3 of the Deep-Sea Drilling Project",
    year = "1974",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Basalts cored on legs 2 and 3 of the Deep-Sea Drilling Project (DSDP) range in sea floor spreading age from 18 to 67×106 yr. Although many of the basalts are highly altered, fresh glass is usually present. Except for site 2–10 the fresh glasses are petrographically and geochemically similar to mid-Atlantic ridge (MAR) axial basalts. There are no systematic compositional differences as a function of distance from the MAR axis. Two sites contain basalts with olivine (Fo90) phenocrysts, high Mg/Mg + ΣFe, high Ni and Cr abundances, and very low large ion lithophile (LIL) element abundances. These basalts are the best candidates for primary magma recovered from the sea floor; fractional crystallization of such basalt may yield the more evolved basalts typical of the MAR. More fractionated basalts with clinopyroxene phenocrysts occur at twp other sites, but they retain low LIL element abundances. Site 2-10 contains titaniferous augite and is relatively enriched in LIL elements. It is unlikely that this basalt was derived by fractional crystallization from LIL element depleted tholeiites; instead, the site 2-10 basalt requires a different mantle source. These results imply that the upper Atlantic Ocean basement is dominantly LIL element depleted tholeiite.",
    url = "https://doi.org/10.1029/jb079i035p05507",
    doi = "10.1029/jb079i035p05507",
    openalex = "W2143836610",
    references = "doi101007bf00371276, doi101007bf00372052, doi1010160012821x70900580, doi1010160012825268901475, doi1010160016703768901087, doi1010160016703770901109, doi101016s0012821x6880010x, doi101038242565a0, doi101093petrology33342, doi101139e67004"
}

@incollection{doi102973dsdpproc251341974,
    author = "Schlich, R. and Simpson, Edward and Vallier, T.L.",
    title = "Regional Aspects of Deep Sea Drilling in the Western Indian Ocean, Leg 25, DSDP",
    year = "1974",
    booktitle = "U.S. Government Printing Office eBooks",
    url = "https://doi.org/10.2973/dsdp.proc.25.134.1974",
    doi = "10.2973/dsdp.proc.25.134.1974",
    openalex = "W2500793984"
}

ABSTRACT Reduction of sediment porosity and increase in density under overburden pressure in the sea floor are important subjects in earth sciences. Data and samples from the Deep Sea Drilling Project allow a new look at these subjects, and are used to establish profiles of laboratory values of density and porosity versus depth in the sea floor. To construct in situ profiles, the results of consolidation tests are used to estimate the amount of elastic rebound (increase in volume) which has occurred after removal of the samples from overburden pressure in the boreholes. In situ profiles of porosity and density versus depth are constructed for some important sediment types: calcareous ooze, siliceous oozes (diatomaceous and radiolarian oozes), pelagic clay, and terrigenous sediments. There is l ss reduction of porosity with depth in the first 100 m in these deep-water sediments than previously supposed: 8 to 9% in pelagic clay, calcareous and terrigenous sediments, and only 4 to 5% in the siliceous sediments. From depths of 300 m the most rebound is in pelagic clay (about 7%), and the least in diatomaceous ooze (about 2%); calcareous ooze and terrigenous sediment should rebound from 300 m about 4 to 5%. Terrigenous sediment, from the surface to 1,000 m depth, probably rebounds a maximum of about 9%. Methods are described and illustrated to predict density and porosity gradients in the sea floor, and to compute the amounts of original sediments necessary to have been compressed to present thicknesses. Slightly over 2,000 m of original sediments would have been required for compr ssion to a present-day thickness of 1,000 m of terrigenous sediments.

@article{doi101306212f6f3c2b2411d78648000102c1865d,
    author = "Hamilton, Edwin L.",
    title = "Variations of Density and Porosity with Depth in Deep-sea Sediments",
    year = "1976",
    journal = "Journal of Sedimentary Research",
    abstract = "ABSTRACT Reduction of sediment porosity and increase in density under overburden pressure in the sea floor are important subjects in earth sciences. Data and samples from the Deep Sea Drilling Project allow a new look at these subjects, and are used to establish profiles of laboratory values of density and porosity versus depth in the sea floor. To construct in situ profiles, the results of consolidation tests are used to estimate the amount of elastic rebound (increase in volume) which has occurred after removal of the samples from overburden pressure in the boreholes. In situ profiles of porosity and density versus depth are constructed for some important sediment types: calcareous ooze, siliceous oozes (diatomaceous and radiolarian oozes), pelagic clay, and terrigenous sediments. There is l ss reduction of porosity with depth in the first 100 m in these deep-water sediments than previously supposed: 8 to 9\% in pelagic clay, calcareous and terrigenous sediments, and only 4 to 5\% in the siliceous sediments. From depths of 300 m the most rebound is in pelagic clay (about 7\%), and the least in diatomaceous ooze (about 2\%); calcareous ooze and terrigenous sediment should rebound from 300 m about 4 to 5\%. Terrigenous sediment, from the surface to 1,000 m depth, probably rebounds a maximum of about 9\%. Methods are described and illustrated to predict density and porosity gradients in the sea floor, and to compute the amounts of original sediments necessary to have been compressed to present thicknesses. Slightly over 2,000 m of original sediments would have been required for compr ssion to a present-day thickness of 1,000 m of terrigenous sediments.",
    url = "https://doi.org/10.1306/212f6f3c-2b24-11d7-8648000102c1865d",
    doi = "10.1306/212f6f3c-2b24-11d7-8648000102c1865d",
    openalex = "W1993200857"
}

Deep‐sea drilling in the Antarctic region (Deep‐Sea Drilling Project legs 28, 29, 35, and 36) has provided many new data about the development of circum‐Antarctic circulation and the closely related glacial evolution of Antarctica. The Antarctic continent has been in a high‐latitude position since the middle to late Mesozoic. Glaciation commenced much later, in the middle Tertiary, demonstrating that near‐polar position is not sufficient for glacial development. Instead, continental glaciation developed as the present‐day Southern Ocean circulation system became established when obstructing land masses moved aside. During the Paleocene (t = ∼65 to 55 m.y. ago), Australia and Antarctica were joined. In the early Eocene (t = ∼55 m.y. ago), Australia began to drift northward from Antarctica, forming an ocean, although circum‐Antarctic flow was blocked by the continental South Tasman Rise and Tasmania. During the Eocene (t = 55 to 38 m.y. ago) the Southern Ocean was relatively warm and the continent largely nonglaciated. Cool temperate vegetation existed in some regions. By the late Eocene (t = ∼39 m.y. ago) a shallow water connection had developed between the southern Indian and Pacific oceans over the South Tasman Rise. The first major climatic‐glacial threshold was crossed 38 m.y. ago near the Eocene‐Oligocene boundary, when substantial Antarctic sea ice began to form. This resulted in a rapid temperature drop in bottom waters of about 5°C and a major crisis in deep‐sea faunas. Thermohaline oceanic circulation was initiated at this time much like that of the present day. The resulting change in climatic regime increased bottom water activity over wide areas of the deep ocean basins, creating much sediment erosion, especially in western parts of oceans. A major (∼2000 m) and apparently rapid deepening also occurred in the calcium carbonate compensation depth (CCD). This climatic threshold was crossed as a result of the gradual isolation of Antarctica from Australia and perhaps the opening of the Drake Passage. During the Oligocene (t = 38 to 22 m.y. ago), widespread glaciation probably occurred throughout Antarctica, although no ice cap existed. By the middle to late Oligocene (t = ∼30 to 25 m.y. ago), deep‐seated circum‐Antarctic flow had developed south of the South Tasman Rise, as this had separated sufficiently from Victoria Land, Antarctica. Major reorganization resulted in southern hemisphere deep‐sea sediment distribution patterns. The next principal climatic threshold was crossed during the middle Miocene (t = 14 to 11 m.y. ago) when the Antarctic ice cap formed. This occurred at about the time of closure of the Australian‐Indonesian deep‐sea passage. During the early Miocene, calcareous biogenic sediments began to be displaced northward by siliceous biogenic sediments with higher rates of sedimentation reflecting the beginning of circulation related to the development of the Antarctic Convergence. Since the middle Miocene the East Antarctic ice cap has remained a semipermanent feature exhibiting some changes in volume. The most important of these occurred during the latest Miocene (t = ∼5 m.y. ago) when ice volumes increased beyond those of the present day. This event was related to global climatic cooling, a rapid northward movement of about 300 km of the Antarctic Convergence, and a eustatic sea level drop that may have been partly responsible for the isolation of the Mediterranean basin. Northern hemisphere ice sheet development began about 2.5–3 m.y. ago, representing the next major global climatic threshold, and was followed by the well‐known major oscillations in northern ice sheets. In the Southern Ocean the Quaternary marks a peak in activity of oceanic circulation as reflected by widespread deep‐sea erosion, very high biogenic productivity at the Antarctic Convergence and resulting high rates of biogenic sedimentation, and maximum northward distribution of ice‐rafted debris.

@article{doi101029jc082i027p03843,
    author = "Kennett, James P.",
    title = "Cenozoic evolution of Antarctic glaciation, the circum-Antarctic Ocean, and their impact on global paleoceanography",
    year = "1977",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "Deep‐sea drilling in the Antarctic region (Deep‐Sea Drilling Project legs 28, 29, 35, and 36) has provided many new data about the development of circum‐Antarctic circulation and the closely related glacial evolution of Antarctica. The Antarctic continent has been in a high‐latitude position since the middle to late Mesozoic. Glaciation commenced much later, in the middle Tertiary, demonstrating that near‐polar position is not sufficient for glacial development. Instead, continental glaciation developed as the present‐day Southern Ocean circulation system became established when obstructing land masses moved aside. During the Paleocene (t = ∼65 to 55 m.y. ago), Australia and Antarctica were joined. In the early Eocene (t = ∼55 m.y. ago), Australia began to drift northward from Antarctica, forming an ocean, although circum‐Antarctic flow was blocked by the continental South Tasman Rise and Tasmania. During the Eocene (t = 55 to 38 m.y. ago) the Southern Ocean was relatively warm and the continent largely nonglaciated. Cool temperate vegetation existed in some regions. By the late Eocene (t = ∼39 m.y. ago) a shallow water connection had developed between the southern Indian and Pacific oceans over the South Tasman Rise. The first major climatic‐glacial threshold was crossed 38 m.y. ago near the Eocene‐Oligocene boundary, when substantial Antarctic sea ice began to form. This resulted in a rapid temperature drop in bottom waters of about 5°C and a major crisis in deep‐sea faunas. Thermohaline oceanic circulation was initiated at this time much like that of the present day. The resulting change in climatic regime increased bottom water activity over wide areas of the deep ocean basins, creating much sediment erosion, especially in western parts of oceans. A major (∼2000 m) and apparently rapid deepening also occurred in the calcium carbonate compensation depth (CCD). This climatic threshold was crossed as a result of the gradual isolation of Antarctica from Australia and perhaps the opening of the Drake Passage. During the Oligocene (t = 38 to 22 m.y. ago), widespread glaciation probably occurred throughout Antarctica, although no ice cap existed. By the middle to late Oligocene (t = ∼30 to 25 m.y. ago), deep‐seated circum‐Antarctic flow had developed south of the South Tasman Rise, as this had separated sufficiently from Victoria Land, Antarctica. Major reorganization resulted in southern hemisphere deep‐sea sediment distribution patterns. The next principal climatic threshold was crossed during the middle Miocene (t = 14 to 11 m.y. ago) when the Antarctic ice cap formed. This occurred at about the time of closure of the Australian‐Indonesian deep‐sea passage. During the early Miocene, calcareous biogenic sediments began to be displaced northward by siliceous biogenic sediments with higher rates of sedimentation reflecting the beginning of circulation related to the development of the Antarctic Convergence. Since the middle Miocene the East Antarctic ice cap has remained a semipermanent feature exhibiting some changes in volume. The most important of these occurred during the latest Miocene (t = ∼5 m.y. ago) when ice volumes increased beyond those of the present day. This event was related to global climatic cooling, a rapid northward movement of about 300 km of the Antarctic Convergence, and a eustatic sea level drop that may have been partly responsible for the isolation of the Mediterranean basin. Northern hemisphere ice sheet development began about 2.5–3 m.y. ago, representing the next major global climatic threshold, and was followed by the well‐known major oscillations in northern ice sheets. In the Southern Ocean the Quaternary marks a peak in activity of oceanic circulation as reflected by widespread deep‐sea erosion, very high biogenic productivity at the Antarctic Convergence and resulting high rates of biogenic sedimentation, and maximum northward distribution of ice‐rafted debris.",
    url = "https://doi.org/10.1029/jc082i027p03843",
    doi = "10.1029/jc082i027p03843",
    openalex = "W2016564007",
    references = "doi1010160025322771900533, doi1010160025322777900457, doi1010160033589473900525, doi1010160033589476900478, doi101017s0032247400063804, doi101038260513a0, doi101086626295, doi102475ajs2683193, doi102973dsdpproc291171975, doi102973dsdpproc291975"
}

We establish a simple relation between subsidence and age for both normal ocean floor and the aseismic ridges in the Indian Ocean. This subsidence is accounted for by the cooling and contraction of the lithospheric plate as it moves away from a center of spreading. We use the relation between subsidence and age to construct paleobathymetric charts of the ocean for the early Oligocene (36 m.y.b.p.), the early Eocene (53 m.y.b.p.) and the late Cretaceous (70 m.y.b.p.). We conclude from these charts that the Indian Ocean between the middle Cretaceous and the Oligocene may have been separated by the Ninetyeast Ridge/Kerguelen Plateau complex and the Madagascar, Amirantes, Mascarene, Chagos complex into three basins which were not connected at depths below 2,000 m. We discuss the implications these complexes and the active mid-ocean ridge axis may have had for deep water circulation patterns in the Indian Ocean. As an example of the application of these charts we use 19 drill sites to reconstruct the past history of the Calcite Compensation Depth (CCD) in the Indian Ocean. The average depth of this boundary shallows from more than 4,500 m at present to 4,000 m in the Oligocène and remains approximately constant till the Campanian. In the Wharton Basin it shallows in the Albian and Aptian. Major differences from the average in the Northern Arabian Sea and the Australia and Antarctic Basins can be accounted for by proximity to the continental shelf and the presence of bottom water in the Antarctic Circumpolar Current. We assume a constant CCD of 4,000 m for the rest of the Indian Ocean and compute the surface distribution of carbonate and clay sediments in the Oligocene. The shallowing of the CCD results in a marked reduction in the surface distribution of calcareous sediments between the present and the Oligocene. The reason for such a dramatic diminution of carbonate sediments is not known.

@incollection{doi101029sp009p0025,
    author = "Sclater, John G. and Abbott, Dallas and Thiede, Jörn",
    title = "Paleobathymetry and sediments of the Indian Ocean",
    year = "1977",
    booktitle = "American Geophysical Union eBooks",
    abstract = "We establish a simple relation between subsidence and age for both normal ocean floor and the aseismic ridges in the Indian Ocean. This subsidence is accounted for by the cooling and contraction of the lithospheric plate as it moves away from a center of spreading. We use the relation between subsidence and age to construct paleobathymetric charts of the ocean for the early Oligocene (36 m.y.b.p.), the early Eocene (53 m.y.b.p.) and the late Cretaceous (70 m.y.b.p.). We conclude from these charts that the Indian Ocean between the middle Cretaceous and the Oligocene may have been separated by the Ninetyeast Ridge/Kerguelen Plateau complex and the Madagascar, Amirantes, Mascarene, Chagos complex into three basins which were not connected at depths below 2,000 m. We discuss the implications these complexes and the active mid-ocean ridge axis may have had for deep water circulation patterns in the Indian Ocean. As an example of the application of these charts we use 19 drill sites to reconstruct the past history of the Calcite Compensation Depth (CCD) in the Indian Ocean. The average depth of this boundary shallows from more than 4,500 m at present to 4,000 m in the Oligocène and remains approximately constant till the Campanian. In the Wharton Basin it shallows in the Albian and Aptian. Major differences from the average in the Northern Arabian Sea and the Australia and Antarctic Basins can be accounted for by proximity to the continental shelf and the presence of bottom water in the Antarctic Circumpolar Current. We assume a constant CCD of 4,000 m for the rest of the Indian Ocean and compute the surface distribution of carbonate and clay sediments in the Oligocene. The shallowing of the CCD results in a marked reduction in the surface distribution of calcareous sediments between the present and the Oligocene. The reason for such a dramatic diminution of carbonate sediments is not known.",
    url = "https://doi.org/10.1029/sp009p0025",
    doi = "10.1029/sp009p0025",
    openalex = "W1582151101",
    references = "doi102973dsdpproc251341974"
}

@misc{langseth1977the4,
    author = "Langseth, M",
    title = "The seafloor and the Earth's heat engine",
    year = "1977",
    howpublished = "Lamont-Doherty Geological Observatory Yearbook, v. 4, p. 41-44",
    note = "talkorigins\_source = {true}; raw\_reference = {Langseth, M., 1977, The seafloor and the Earth's heat engine: Lamont-Doherty Geological Observatory Yearbook, v. 4, p. 41-44.}"
}

@article{doi101038282677a0,
    author = "Eppley, Richard W. and Peterson, Bruce J.",
    title = "Particulate organic matter flux and planktonic new production in the deep ocean",
    year = "1979",
    journal = "Nature",
    url = "https://doi.org/10.1038/282677a0",
    doi = "10.1038/282677a0",
    openalex = "W2078114051",
    references = "doi1010160002157176900601, doi1010160011747175900224, doi1010160031018268900473, doi101016019801497990089x, doi101029jc084ic06p03218, doi1023072402277, doi104319lo19671220196, doi104319lo19721750738, doi104319lo19792430483, openalexw102554850"
}

@misc{hall1979deep2,
    author = "Hall, J. M. and Robinson, P. T",
    title = "Deep crustal drilling in the north Atlantic Ocean",
    year = "1979",
    howpublished = "Science, v. 204, p. 573-586",
    note = "talkorigins\_source = {true}; raw\_reference = {Hall, J. M., and Robinson, P. T., 1979, Deep crustal drilling in the north Atlantic Ocean: Science, v. 204, p. 573-586.}"
}

@misc{woodruff1981miocene8,
    author = "Woodruff, F. and Savin, S. M. and Douglas, R. G",
    title = "Miocene stable isotope record",
    year = "1981",
    howpublished = "a detailed deep Pacific Ocean Study and its paleoclimatic implications: Science, v. 212, p. 665-668",
    note = "talkorigins\_source = {true}; raw\_reference = {Woodruff, F., Savin, S. M., and Douglas, R. G., 1981, Miocene stable isotope record: a detailed deep Pacific Ocean Study and its paleoclimatic implications: Science, v. 212, p. 665-668.}"
}

@misc{dansgaard1982a1,
    author = "Dansgaard, W. et al",
    title = "A new Greenland deep ice core",
    year = "1982",
    howpublished = "Science, v. 218, p. 1273-1277",
    note = "talkorigins\_source = {true}; raw\_reference = {Dansgaard, W. et al., 1982, A new Greenland deep ice core: Science, v. 218, p. 1273-1277.}"
}

A project to objectively analyze historical ocean temperature, salinity, oxygen, and percent oxygen saturation data for the world ocean has recently been completed at the National Oceanic and Atmospheric Administration's (NOAA) Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey. The results of the project are being made available through distribution of the Climatological Atlas of the World Ocean (NOAA Professional Paper No. 13), and through distribution of magnetic tapes containing the objective analyses. The sources of data used in the project were the Station Data, Mechanical Bathythermograph, and Expendable Bathythermograph files of the National Oceanographic Data Center (NODC) in Washington, D.C., updated through 1977–1978. The raw data were subjected to quality control procedures, averaged by one‐degree squares, and then used as input to an objective analysis procedure that fills in one‐degree squares containing no data and smooths the results. Due to the lack of synoptic observations for the world ocean, the historical data are composited by annual, seasonal, and (for temperature) monthly periods.

@article{doi101029eo064i049p0096202,
    author = "Levitus, Sydney",
    title = "Climatological Atlas of the World Ocean",
    year = "1983",
    journal = "Eos",
    abstract = "A project to objectively analyze historical ocean temperature, salinity, oxygen, and percent oxygen saturation data for the world ocean has recently been completed at the National Oceanic and Atmospheric Administration's (NOAA) Geophysical Fluid Dynamics Laboratory, Princeton, New Jersey. The results of the project are being made available through distribution of the Climatological Atlas of the World Ocean (NOAA Professional Paper No. 13), and through distribution of magnetic tapes containing the objective analyses. The sources of data used in the project were the Station Data, Mechanical Bathythermograph, and Expendable Bathythermograph files of the National Oceanographic Data Center (NODC) in Washington, D.C., updated through 1977–1978. The raw data were subjected to quality control procedures, averaged by one‐degree squares, and then used as input to an objective analysis procedure that fills in one‐degree squares containing no data and smooths the results. Due to the lack of synoptic observations for the world ocean, the historical data are composited by annual, seasonal, and (for temperature) monthly periods.",
    url = "https://doi.org/10.1029/eo064i049p00962-02",
    doi = "10.1029/eo064i049p00962-02",
    openalex = "W2000756370"
}

New data and new estimates from old data show that rivers with large sediment loads (annual discharges greater than about tons) contribute about tons of suspended sediment to the ocean yearly. Extrapolating available data for all drainage basins, the total suspended sediment delivered by all rivers to the oceans is about tons annually; bedload and flood discharges may account for an additional tons. About 70% of this total is derived from southern Asia and the larger islands in the Pacific and Indian Oceans, where sediment yields are much greater than for other drainage basins.

@article{doi101086628741,
    author = "Milliman, John D. and Meade, Robert H.",
    title = "World-Wide Delivery of River Sediment to the Oceans",
    year = "1983",
    journal = "The Journal of Geology",
    abstract = "New data and new estimates from old data show that rivers with large sediment loads (annual discharges greater than about tons) contribute about tons of suspended sediment to the ocean yearly. Extrapolating available data for all drainage basins, the total suspended sediment delivered by all rivers to the oceans is about tons annually; bedload and flood discharges may account for an additional tons. About 70\% of this total is derived from southern Asia and the larger islands in the Pacific and Indian Oceans, where sediment yields are much greater than for other drainage basins.",
    url = "https://doi.org/10.1086/628741",
    doi = "10.1086/628741",
    openalex = "W2041158780",
    references = "doi1010160025322781901663, doi101029wr004i004p00737, doi101038278161a0, doi1010970001069419610800000029, doi101130001676061967781203tgotar20co2, doi1011300091761319764105dotist20co2, doi101130gsabp2911, doi101306m20377, doi102110pec7203, doi102110pec7217"
}

@misc{smith1985source7,
    author = "Smith, G. M",
    title = "Source of marine magnetic anomalies; some results from DSDP Leg 83",
    year = "1985",
    howpublished = "Geology, v. 13, p. 162-165",
    note = "talkorigins\_source = {true}; raw\_reference = {Smith, G. M., 1985, Source of marine magnetic anomalies; some results from DSDP Leg 83: Geology, v. 13, p. 162-165.}"
}

Two stable equilibria have been obtained from a global model of the coupled ocean-atmosphere system developed at the Geophysical Fluid Dynamics Laboratory of NOAA. The model used for this study consists of general circulation models of the atmosphere and the world oceans and a simple model of land surface. Starting from two different initial conditions, “asynchronous” time integrations of the coupled model, under identical boundary conditions, lead to two stable equilibria. In one equilibrium, the North Atlantic Oman has a vigorous thermohaline circulation and relatively saline and warm surface water. In the other equilibrium, there is no thermohaline circulation, and an intense halocline exists in the surface layer at high latitudes. In both integration the, air-sea exchange of water is adjusted to remove a systematic bias of the model that surpresses the thermohaline circulation in the North Atlantic. Nevertheless these results raise the intriguing possibility that the coupled system may have at least two equilibria. They also suggest that the themohaline overturning in the North Atlantic is mainly responsible for making the surface salinity of the northern North Atlantic higher than that of the northern North Pacific. Finally, a discussion is made on the paleoclimatic implications of these results for the large and abrupt transition between the Alleröd and Younger Dryas events which occurred about 11 000 years ago.

@article{doi1011751520044219880010841tseoac20co2,
    author = "Manabe, Syukuro and Stouffer, Ronald J.",
    title = "Two Stable Equilibria of a Coupled Ocean-Atmosphere Model",
    year = "1988",
    journal = "Journal of Climate",
    abstract = "Two stable equilibria have been obtained from a global model of the coupled ocean-atmosphere system developed at the Geophysical Fluid Dynamics Laboratory of NOAA. The model used for this study consists of general circulation models of the atmosphere and the world oceans and a simple model of land surface. Starting from two different initial conditions, “asynchronous” time integrations of the coupled model, under identical boundary conditions, lead to two stable equilibria. In one equilibrium, the North Atlantic Oman has a vigorous thermohaline circulation and relatively saline and warm surface water. In the other equilibrium, there is no thermohaline circulation, and an intense halocline exists in the surface layer at high latitudes. In both integration the, air-sea exchange of water is adjusted to remove a systematic bias of the model that surpresses the thermohaline circulation in the North Atlantic. Nevertheless these results raise the intriguing possibility that the coupled system may have at least two equilibria. They also suggest that the themohaline overturning in the North Atlantic is mainly responsible for making the surface salinity of the northern North Atlantic higher than that of the northern North Pacific. Finally, a discussion is made on the paleoclimatic implications of these results for the large and abrupt transition between the Alleröd and Younger Dryas events which occurred about 11 000 years ago.",
    url = "https://doi.org/10.1175/1520-0442(1988)001<0841:tseoac>2.0.co;2",
    doi = "10.1175/1520-0442(1988)001<0841:tseoac>2.0.co;2",
    openalex = "W2083356111",
    references = "doi1010160079661182900064, doi101357002224083788520207"
}

@article{doi101038342637a0,
    author = "Fairbanks, Richard G.",
    title = "A 17,000-year glacio-eustatic sea level record: influence of glacial melting rates on the Younger Dryas event and deep-ocean circulation",
    year = "1989",
    journal = "Nature",
    url = "https://doi.org/10.1038/342637a0",
    doi = "10.1038/342637a0",
    openalex = "W2094394939",
    references = "doi1010160031018281900973, doi1010160033589478900339, doi101016003358947890100x, doi1010160033589484900929, doi101029pa003i001p00001, doi101029pa003i006p00635, doi101038330035a0, doi101038339532a0, doi101038341318a0, doi101126science23648081547"
}

The conditions necessary for compressive and tensile failure of well bores drilled into crystalline rock can be adequately represented by simple elastic failure criteria, and analysis of well bore failure can provide constraints on the magnitudes of in situ stresses if the strength of the rock is known. When applied to several boreholes drilled into continental crust where there is relatively complete knowledge of stress magnitudes, these criteria enable us to predict the depth at which compressive failure of the well bores is observed. In oceanic crust, breakouts have been observed at depths below 700 m below sea floor in Deep Sea Drilling Project (DSDP) hole 504B, drilled into 5.9 Ma crust south of the Costa Rica Rift, and near the bottom of DSDP hole 395A, drilled into 7.3 Ma crust west of the Mid–Atlantic Ridge. In both cases the azimuth of maximum horizontal compressive stress is roughly perpendicular to the ridge axis. As the unconfined compressive strengths of basalt samples from DSDP hole 504B are generally above 200 MPa (Bauer and Handin, 1985), the existence of breakouts in DSDP holes 395A and 504B requires a highly compressional stress state, where S hmin ∼ S v and S Hmax ≥ 100 Mpa at about 500 m subbasement. These results are consistent with the state of stress inferred from compressional (strike‐slip and reverse faulting) earthquake focal mechanisms in young oceanic crust. As ridge push forces are relatively small in young oceanic crust, we concur with previous suggestions that the high horizontal compressive stresses result from the thermoelastic effects of a convectively cooled upper crustal layer overlying a conductively cooling lithosphere.

@article{doi101029jb095ib06p09305,
    author = "Moos, Daniel and Zoback, Mark D.",
    title = "Utilization of observations of well bore failure to constrain the orientation and magnitude of crustal stresses: Application to continental, Deep Sea Drilling Project, and Ocean Drilling Program boreholes",
    year = "1990",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "The conditions necessary for compressive and tensile failure of well bores drilled into crystalline rock can be adequately represented by simple elastic failure criteria, and analysis of well bore failure can provide constraints on the magnitudes of in situ stresses if the strength of the rock is known. When applied to several boreholes drilled into continental crust where there is relatively complete knowledge of stress magnitudes, these criteria enable us to predict the depth at which compressive failure of the well bores is observed. In oceanic crust, breakouts have been observed at depths below 700 m below sea floor in Deep Sea Drilling Project (DSDP) hole 504B, drilled into 5.9 Ma crust south of the Costa Rica Rift, and near the bottom of DSDP hole 395A, drilled into 7.3 Ma crust west of the Mid–Atlantic Ridge. In both cases the azimuth of maximum horizontal compressive stress is roughly perpendicular to the ridge axis. As the unconfined compressive strengths of basalt samples from DSDP hole 504B are generally above 200 MPa (Bauer and Handin, 1985), the existence of breakouts in DSDP holes 395A and 504B requires a highly compressional stress state, where S hmin ∼ S v and S Hmax ≥ 100 Mpa at about 500 m subbasement. These results are consistent with the state of stress inferred from compressional (strike‐slip and reverse faulting) earthquake focal mechanisms in young oceanic crust. As ridge push forces are relatively small in young oceanic crust, we concur with previous suggestions that the high horizontal compressive stresses result from the thermoelastic effects of a convectively cooled upper crustal layer overlying a conductively cooling lithosphere.",
    url = "https://doi.org/10.1029/jb095ib06p09305",
    doi = "10.1029/jb095ib06p09305",
    openalex = "W2035630376",
    references = "doi101007bf00876528, doi1010160040195179900817, doi1010160148906274922050, doi101017cbo9780511735349, doi101029jb085ib11p06113, doi101029jb085ib11p06248, doi101126science23848301105, doi101130mem97, doi102118686g, openalexw3118324657"
}

@book{doi101007bfb0010382,
    author = "Stein, Ruediger",
    title = "Accumulation of organic carbon in marine sediments: results from the Deep Sea Drilling Project/Ocean Drilling Program (DSDP/ODP)",
    year = "1991",
    url = "https://doi.org/10.1007/bfb0010382",
    doi = "10.1007/bfb0010382",
    openalex = "W1655966245"
}

We used sediment traps to define the particulate fluxes of barium and organic carbon and investigate the use of barium as a proxy for ocean fertility. Strong correlations between C org and Ba fluxes indicate a link between upper ocean biological processes and barium flux to the seafloor. The ratio of organic carbon to barium decreases systematically with water depth. Data from 10 sites indicate that organic debris settling from the 200‐m depth has a C org /Ba ratio of approximately 200. The systematic decrease in this ratio with increasing water depth results from the simultaneous decay of organic matter and uptake of Ba in settling particles. This behavior provides additional evidence that the formation of barite in oceanic particles is a consequence of decomposition/uptake in microenvironments rather than the secretion of barite by specific organisms. The decrease of the Corg/Ba ratio with depth is greatest in the North Pacific followed by the equatorial Pacific and is lowest in the western Atlantic. Since this spatial pattern is consistent with the variations in the deep‐ocean barium contents which increase along the path of bottom water flow from the Atlantic to the North Pacific, it suggests that the particulate barium uptake and flux is enhanced by higher barium contents in the intermediate and deep waters of the ocean. Consequently, we have combined our particle flux data with existing water column Ba data to define an algorithm relating new productivity, dissolved barium contents, water depth, and particulate barium flux. This relationship provides a basis of applying barium flux measurements in sediments to estimating new production. In order to use barium as an indicator of productivity, it will be necessary to evaluate inputs from hydrothermal and aluminosilicate sources and xenophyophors. The application of a sequential leach procedure to the trap material indicates that 50‐70% of the Ba in settling particles is in the form of barite and the remaining is adsorbed or bound to carbonates. Normative analysis demonstrates that in nearshore areas the contribution of barium from aluminosilicate sources can dominate that from biogenic inputs. It appears that normative estimates of biogenic barium contents can be made with accuracy if less than 50% of the Ba is associated with aluminosilicates; i.e., is of terrigenous origin. Since diagenetic mobilization of Ba can occur in reduced and suboxic sediments, highly productive nearshore areas also are likely to be inappropriate sites to use Ba measurements as productivity indicators. Comparisons between the rain rates of particulate Ba to the seafloor and the burial rate indicate that approximately 30% of the Ba rain is preserved. Although the preservation factor does not appear to be constant, it may be possible to predict the extent of preservation from an empirical relationship with the mass accumulation rate. These observations indicate that measurement of Ba burial fluxes in sediments can provide quantitative information on the paleoproductivity of the oceans. Joining the relationship between barium rain and burial with the barium and organic carbon algorithm, we make estimates of the new production in the northern California Current during the last 18,000 years. This calculation suggests that new production was at least a factor of 2 lower at this site during the last glacial maximum.

@article{doi10102992pa00181,
    author = "Dymond, Jack and Suess, Erwin and Lyle, Mitchell W",
    title = "Barium in Deep‐Sea Sediment: A Geochemical Proxy for Paleoproductivity",
    year = "1992",
    journal = "Paleoceanography",
    abstract = "We used sediment traps to define the particulate fluxes of barium and organic carbon and investigate the use of barium as a proxy for ocean fertility. Strong correlations between C org and Ba fluxes indicate a link between upper ocean biological processes and barium flux to the seafloor. The ratio of organic carbon to barium decreases systematically with water depth. Data from 10 sites indicate that organic debris settling from the 200‐m depth has a C org /Ba ratio of approximately 200. The systematic decrease in this ratio with increasing water depth results from the simultaneous decay of organic matter and uptake of Ba in settling particles. This behavior provides additional evidence that the formation of barite in oceanic particles is a consequence of decomposition/uptake in microenvironments rather than the secretion of barite by specific organisms. The decrease of the Corg/Ba ratio with depth is greatest in the North Pacific followed by the equatorial Pacific and is lowest in the western Atlantic. Since this spatial pattern is consistent with the variations in the deep‐ocean barium contents which increase along the path of bottom water flow from the Atlantic to the North Pacific, it suggests that the particulate barium uptake and flux is enhanced by higher barium contents in the intermediate and deep waters of the ocean. Consequently, we have combined our particle flux data with existing water column Ba data to define an algorithm relating new productivity, dissolved barium contents, water depth, and particulate barium flux. This relationship provides a basis of applying barium flux measurements in sediments to estimating new production. In order to use barium as an indicator of productivity, it will be necessary to evaluate inputs from hydrothermal and aluminosilicate sources and xenophyophors. The application of a sequential leach procedure to the trap material indicates that 50‐70\% of the Ba in settling particles is in the form of barite and the remaining is adsorbed or bound to carbonates. Normative analysis demonstrates that in nearshore areas the contribution of barium from aluminosilicate sources can dominate that from biogenic inputs. It appears that normative estimates of biogenic barium contents can be made with accuracy if less than 50\% of the Ba is associated with aluminosilicates; i.e., is of terrigenous origin. Since diagenetic mobilization of Ba can occur in reduced and suboxic sediments, highly productive nearshore areas also are likely to be inappropriate sites to use Ba measurements as productivity indicators. Comparisons between the rain rates of particulate Ba to the seafloor and the burial rate indicate that approximately 30\% of the Ba rain is preserved. Although the preservation factor does not appear to be constant, it may be possible to predict the extent of preservation from an empirical relationship with the mass accumulation rate. These observations indicate that measurement of Ba burial fluxes in sediments can provide quantitative information on the paleoproductivity of the oceans. Joining the relationship between barium rain and burial with the barium and organic carbon algorithm, we make estimates of the new production in the northern California Current during the last 18,000 years. This calculation suggests that new production was at least a factor of 2 lower at this site during the last glacial maximum.",
    url = "https://doi.org/10.1029/92pa00181",
    doi = "10.1029/92pa00181",
    openalex = "W2156433034",
    references = "doi101038282677a0, doi101038329408a0, doi101038331341a0, doi104319lo19671220196, doi104319lo19842920236"
}

@article{doi1010160031018294902518,
    author = "Flower, B. P. and Kennett, James P.",
    title = "The middle Miocene climatic transition: East Antarctic ice sheet development, deep ocean circulation and global carbon cycling",
    year = "1994",
    journal = "Palaeogeography Palaeoclimatology Palaeoecology",
    url = "https://doi.org/10.1016/0031-0182(94)90251-8",
    doi = "10.1016/0031-0182(94)90251-8",
    openalex = "W2165473271",
    references = "doi101007bf02861083, doi101016004724849090011y, doi1010160305440386900580, doi101016s0047248485800026, doi10102990jb02015, doi101029gm032, doi101029jc082i027p03843, doi101029pa002i001p00001, doi101029pa004i004p00413, doi101038307620a0, doi101126science23547931156, doi1011300091761319920200569eoiseo23co2, doi101146annurevea05050177001535, doi1023071485903, doi102973dsdpproc291171975, openalexw609835849"
}

Estimates of the magnitudes and spatial distribution of potential oceanic methane hydrate reservoirs have been made from pressure‐temperature phase relations and a plausible range of thermal gradients, sediment porosities, and pore fillings taken from published sources, based on two major theories of gas hydrate formation (1) in situ bacterial production and (2) pore fluid expulsion models. The implications of these two models on eventual atmospheric methane release, due to global warming, are briefly examined. The calculated range of methane volumes in oceanic gas hydrates is 26.4 to 139.1 × 10 15 m 3, with the most likely value on the lower end of this range. The results for the bacterial model show a preferential distribution of hydrates at mid‐ to high latitudes, with an equatorial enhancement in the case of the fluid migration model. The latter model also generates a deeper and thicker hydrate stability zone at most latitudes than does the former. Preliminary results suggest that the hydrate distribution predicted by the fluid migration model may be more consistent with observations. However, this preliminary finding is based on a very limited sample size, and there are high uncertainties in the assumptions. The volume of methane hydrate within the uppermost l m of the hydrate stability zone and within 1°‐2°C of the equilibrium curve, assuming in situ bacterial generation, is 0.93–6.32 × 10 12 m 3, or 0.0035–0.012% of the maximal estimated hydrate reservoir. Nevertheless this volume, if released uniformly over the next 100 years, is comparable to current CH 4 release rates for several important CH 4 sources. Corresponding CH 4 volumes calculated using the fluid migration model are nearly 2 orders of magnitude lower.

@article{doi10102994gb00766,
    author = "Gornitz, Vivien and Fung, Inez",
    title = "Potential distribution of methane hydrates in the world's oceans",
    year = "1994",
    journal = "Global Biogeochemical Cycles",
    abstract = "Estimates of the magnitudes and spatial distribution of potential oceanic methane hydrate reservoirs have been made from pressure‐temperature phase relations and a plausible range of thermal gradients, sediment porosities, and pore fillings taken from published sources, based on two major theories of gas hydrate formation (1) in situ bacterial production and (2) pore fluid expulsion models. The implications of these two models on eventual atmospheric methane release, due to global warming, are briefly examined. The calculated range of methane volumes in oceanic gas hydrates is 26.4 to 139.1 × 10 15 m 3, with the most likely value on the lower end of this range. The results for the bacterial model show a preferential distribution of hydrates at mid‐ to high latitudes, with an equatorial enhancement in the case of the fluid migration model. The latter model also generates a deeper and thicker hydrate stability zone at most latitudes than does the former. Preliminary results suggest that the hydrate distribution predicted by the fluid migration model may be more consistent with observations. However, this preliminary finding is based on a very limited sample size, and there are high uncertainties in the assumptions. The volume of methane hydrate within the uppermost l m of the hydrate stability zone and within 1°‐2°C of the equilibrium curve, assuming in situ bacterial generation, is 0.93–6.32 × 10 12 m 3, or 0.0035–0.012\% of the maximal estimated hydrate reservoir. Nevertheless this volume, if released uniformly over the next 100 years, is comparable to current CH 4 release rates for several important CH 4 sources. Corresponding CH 4 volumes calculated using the fluid migration model are nearly 2 orders of magnitude lower.",
    url = "https://doi.org/10.1029/94gb00766",
    doi = "10.1029/94gb00766",
    openalex = "W2136375698",
    references = "doi101007bfb0010382, doi1010160009254188901040, doi101016s0016699506800574, doi10102991rg00969, doi10102993rg00268, doi101029eo064i049p0096202, doi101029gb002i004p00299, doi101038342637a0, doi101086628741, doi1010970001069419730500000019, doi1012019781420008494"
}

High‐resolution benthic oxygen isotope and dust flux records from Ocean Drilling Program site 659 have been analyzed to extend the astronomically calibrated isotope timescale for the Atlantic from 2.85 Ma back to 5 Ma. Spectral analysis of the δ 18 O record indicates that the 41‐kyr period of Earth's orbital obliquity dominates the Pliocene record. This is shown to be true regardless of fundamental changes in the Earth's climate during the Pliocene. However, the cycles of Sahelian aridity fluctuations indicate a shift in spectral character near 3 Ma. From the early Pliocene to 3 Ma, the periodicities were dominantly precessional (19 and 23 kyr) and remained strong until 1.5 Ma. Subsequent to 3 Ma, the variance at the obliquity period (41 kyr) increased. The timescale tuned to precession suggests that the Pliocene was longer than previously estimated by more than 0.5 m.y. The tuned ages for the magnetic boundaries Gauss/Gilbert and Top Cochiti are about 6–8% older than the ages of the conventional timescale. A major phase of Pliocene northern hemisphere ice growth occurred between 3.15 Ma and 2.5 Ma. This was marked by a gradual increase in glacial Atlantic δ 18 O values of 1‰ and an increase in amplitude variations by up to 1.5‰, much larger than in the Pacific deepwater record (site 846). The first maxima occured in cold stages G6‐96 between 2.7 Ma and 2.45 Ma. Prior to 3 Ma, the isotope record is characterized by predominantly low amplitude fluctuations (< 0.7‰.). When obliquity forcing was at its minimum between 4.15 and 3.6 Ma and during the Kaena interval, δ 18 O amplitude fluctuations were minimal. From 4.9 to 4.3 Ma, the δ 18 O values decreased by about 0.5‰, reaching a long‐term minimum at 4.15 Ma, suggesting higher deepwater temperatures or a deglaciation. Deepwater cooling and/or an increase in ice volume is indicated by a series of short‐term δ 18 O fluctuations between 3.8 and 3.6 Ma.

@article{doi10102994pa00208,
    author = "Tiedemann, Ralf and Sarnthein, Michael and Shackleton, Nicholas J",
    title = "Astronomic timescale for the Pliocene Atlantic δ 18 O and dust flux records of Ocean Drilling Program Site 659",
    year = "1994",
    journal = "Paleoceanography",
    abstract = "High‐resolution benthic oxygen isotope and dust flux records from Ocean Drilling Program site 659 have been analyzed to extend the astronomically calibrated isotope timescale for the Atlantic from 2.85 Ma back to 5 Ma. Spectral analysis of the δ 18 O record indicates that the 41‐kyr period of Earth's orbital obliquity dominates the Pliocene record. This is shown to be true regardless of fundamental changes in the Earth's climate during the Pliocene. However, the cycles of Sahelian aridity fluctuations indicate a shift in spectral character near 3 Ma. From the early Pliocene to 3 Ma, the periodicities were dominantly precessional (19 and 23 kyr) and remained strong until 1.5 Ma. Subsequent to 3 Ma, the variance at the obliquity period (41 kyr) increased. The timescale tuned to precession suggests that the Pliocene was longer than previously estimated by more than 0.5 m.y. The tuned ages for the magnetic boundaries Gauss/Gilbert and Top Cochiti are about 6–8\% older than the ages of the conventional timescale. A major phase of Pliocene northern hemisphere ice growth occurred between 3.15 Ma and 2.5 Ma. This was marked by a gradual increase in glacial Atlantic δ 18 O values of 1‰ and an increase in amplitude variations by up to 1.5‰, much larger than in the Pacific deepwater record (site 846). The first maxima occured in cold stages G6‐96 between 2.7 Ma and 2.45 Ma. Prior to 3 Ma, the isotope record is characterized by predominantly low amplitude fluctuations (< 0.7‰.). When obliquity forcing was at its minimum between 4.15 and 3.6 Ma and during the Kaena interval, δ 18 O amplitude fluctuations were minimal. From 4.9 to 4.3 Ma, the δ 18 O values decreased by about 0.5‰, reaching a long‐term minimum at 4.15 Ma, suggesting higher deepwater temperatures or a deglaciation. Deepwater cooling and/or an increase in ice volume is indicated by a series of short‐term δ 18 O fluctuations between 3.8 and 3.6 Ma.",
    url = "https://doi.org/10.1029/94pa00208",
    doi = "10.1029/94pa00208",
    openalex = "W2136923855"
}

We have constructed high‐resolution (10 4 – 10 5 years) benthic foraminiferal δ 13 C and δ 18 O records for the upper Eocene through lower Oligocene of two pelagic sequences, Deep Sea Drilling Project (DSDP) Site 522 in the Angola Basin, South Atlantic Ocean, and Ocean Drilling Program (ODP) Site 744 in the southern Indian Ocean. These records provide improved constraints on both the timing and magnitude of marine oxygen and carbon isotope events from 30 to 35 Ma. The oxygen isotope records indicate that the ubiquitous δ 18 O increase (Oi‐1), which marks the rapid expansion of continental ice sheets and a minimum of 3° to 4°C of cooling of bottom waters in the earliest Oligocene (33.6 Ma), occurred in <350 kyr. More than half the transition occurred over the final 40–50 kyr. This period of lower temperatures and widespread continental glaciation persisted for roughly 400 kyr (i.e., the duration of magnetochron C13n). These records also indicate that this interval was characterized by at least two ∼ 100‐kyr waxing and waning cycles (Oi‐1a and Oi‐1b) and possibly several higher‐frequency events. The benthic foraminiferal δ 13 C records show a positive 0.8‰ excursion that is nearly isochronous with the Oi‐1 oxygen isotope increase. Similar magnitude δ 13 C increases at other sites indicate this was a global phenomenon suggestive of an unusually large perturbation to the carbon cycle. This excursion was followed by smaller amplitude δ 13 C oscillations with periods of roughly ∼400 kyr. We suspect that the ubiquitous Oi‐1 δ 13 C excursion resulted from a brief but substantial increase in export production and carbon burial.

@article{doi10102996pa00571,
    author = "Zachos, James C. and Quinn, Terrence M. and Salamy, Karen A.",
    title = "High‐resolution (10 4 years) deep‐sea foraminiferal stable isotope records of the Eocene‐Oligocene climate transition",
    year = "1996",
    journal = "Paleoceanography",
    abstract = "We have constructed high‐resolution (10 4 – 10 5 years) benthic foraminiferal δ 13 C and δ 18 O records for the upper Eocene through lower Oligocene of two pelagic sequences, Deep Sea Drilling Project (DSDP) Site 522 in the Angola Basin, South Atlantic Ocean, and Ocean Drilling Program (ODP) Site 744 in the southern Indian Ocean. These records provide improved constraints on both the timing and magnitude of marine oxygen and carbon isotope events from 30 to 35 Ma. The oxygen isotope records indicate that the ubiquitous δ 18 O increase (Oi‐1), which marks the rapid expansion of continental ice sheets and a minimum of 3° to 4°C of cooling of bottom waters in the earliest Oligocene (33.6 Ma), occurred in <350 kyr. More than half the transition occurred over the final 40–50 kyr. This period of lower temperatures and widespread continental glaciation persisted for roughly 400 kyr (i.e., the duration of magnetochron C13n). These records also indicate that this interval was characterized by at least two ∼ 100‐kyr waxing and waning cycles (Oi‐1a and Oi‐1b) and possibly several higher‐frequency events. The benthic foraminiferal δ 13 C records show a positive 0.8‰ excursion that is nearly isochronous with the Oi‐1 oxygen isotope increase. Similar magnitude δ 13 C increases at other sites indicate this was a global phenomenon suggestive of an unusually large perturbation to the carbon cycle. This excursion was followed by smaller amplitude δ 13 C oscillations with periods of roughly ∼400 kyr. We suspect that the ubiquitous Oi‐1 δ 13 C excursion resulted from a brief but substantial increase in export production and carbon burial.",
    url = "https://doi.org/10.1029/96pa00571",
    doi = "10.1029/96pa00571",
    openalex = "W2028817233",
    references = "doi1010160012821x74900788, doi1010160025322771900533, doi101016003101829290096n, doi10102990jb02015, doi10102992jb01202, doi101029jc082i027p03843, doi101029pa002i001p00001, doi101029pa002i003p00287, doi101029pa005i001p00001, doi1011751520044219880010841tseoac20co2, doi102475ajs2824451, doi102973dsdpproc291171975, doi102973odpprocsr1192001991"
}

For many years, in situ stress in the brittle crust has been measured at relatively shallow depth and related to the mechanical behavior of the crust as inferred from laboratory studies and faulting theory. A continuous profile of the magnitudes and orientations of the three principal stresses has been estimated to depths of 7.7 km and 8.6 km in the German Continental Deep Drilling Program (KTB). This was achieved by hydraulic fracturing tests at relatively shallow depth (1–3 km), estimates of the magnitude of the least horizontal principal stress provided by modified hydraulic fracturing experiments at 6 km and 9 km depths, and analysis of compressional (breakouts) and tensile (drilling‐induced tensile wall fractures) failures of the borehole wall over nearly the entire depth of the KTB borehole. The orientation of the maximum horizontal principal stress was found to be uniform with depth with an orientation of N160°±10°E, which is consistent with the average orientation found throughout western Europe. The only significant change in stress orientation was observed directly below a major fault zone crosscutting the borehole. The profile of stress magnitudes we have obtained demonstrates that to a depth of 8 km, the state of stress in the brittle crust in southern Germany is in frictional equilibrium. That is, the ratio of shear to normal stress as resolved on preexisting faults which are well‐oriented to the in situ stress field is comparable to their frictional strength based on predictions of Coulomb faulting theory for a coefficient of friction of about 0.7 and near‐hydrostatic pore pressure.

@article{doi10102996jb02942,
    author = "Brudy, Martin and Zoback, Mark D. and Fuchs, Karl and Rummel, F. and Baumgärtner, J.",
    title = "Estimation of the complete stress tensor to 8 km depth in the KTB scientific drill holes: Implications for crustal strength",
    year = "1997",
    journal = "Journal of Geophysical Research Atmospheres",
    abstract = "For many years, in situ stress in the brittle crust has been measured at relatively shallow depth and related to the mechanical behavior of the crust as inferred from laboratory studies and faulting theory. A continuous profile of the magnitudes and orientations of the three principal stresses has been estimated to depths of 7.7 km and 8.6 km in the German Continental Deep Drilling Program (KTB). This was achieved by hydraulic fracturing tests at relatively shallow depth (1–3 km), estimates of the magnitude of the least horizontal principal stress provided by modified hydraulic fracturing experiments at 6 km and 9 km depths, and analysis of compressional (breakouts) and tensile (drilling‐induced tensile wall fractures) failures of the borehole wall over nearly the entire depth of the KTB borehole. The orientation of the maximum horizontal principal stress was found to be uniform with depth with an orientation of N160°±10°E, which is consistent with the average orientation found throughout western Europe. The only significant change in stress orientation was observed directly below a major fault zone crosscutting the borehole. The profile of stress magnitudes we have obtained demonstrates that to a depth of 8 km, the state of stress in the brittle crust in southern Germany is in frictional equilibrium. That is, the ratio of shear to normal stress as resolved on preexisting faults which are well‐oriented to the in situ stress field is comparable to their frictional strength based on predictions of Coulomb faulting theory for a coefficient of friction of about 0.7 and near‐hydrostatic pore pressure.",
    url = "https://doi.org/10.1029/96jb02942",
    doi = "10.1029/96jb02942",
    openalex = "W2083678379",
    references = "doi101029jb095ib06p09305, doi101038341291a0"
}

Changes in oceanic primary production, linked to changes in the network of global biogeochemical cycles, have profoundly influenced the geochemistry of Earth for over 3 billion years. In the contemporary ocean, photosynthetic carbon fixation by marine phytoplankton leads to formation of approximately 45 gigatons of organic carbon per annum, of which 16 gigatons are exported to the ocean interior. Changes in the magnitude of total and export production can strongly influence atmospheric CO2 levels (and hence climate) on geological time scales, as well as set upper bounds for sustainable fisheries harvest. The two fluxes are critically dependent on geophysical processes that determine mixed-layer depth, nutrient fluxes to and within the ocean, and food-web structure. Because the average turnover time of phytoplankton carbon in the ocean is on the order of a week or less, total and export production are extremely sensitive to external forcing and consequently are seldom in steady state. Elucidating the biogeochemical controls and feedbacks on primary production is essential to understanding how oceanic biota responded to and affected natural climatic variability in the geological past, and will respond to anthropogenically influenced changes in coming decades. One of the most crucial feedbacks results from changes in radiative forcing on the hydrological cycle, which influences the aeolian iron flux and, in turn, affects nitrogen fixation and primary production in the oceans.

@article{doi101126science2815374200,
    author = "Falkowski, Paul G. and Barber, Richard T. and Smetacek, Victor",
    title = "Biogeochemical Controls and Feedbacks on Ocean Primary Production",
    year = "1998",
    journal = "Science",
    abstract = "Changes in oceanic primary production, linked to changes in the network of global biogeochemical cycles, have profoundly influenced the geochemistry of Earth for over 3 billion years. In the contemporary ocean, photosynthetic carbon fixation by marine phytoplankton leads to formation of approximately 45 gigatons of organic carbon per annum, of which 16 gigatons are exported to the ocean interior. Changes in the magnitude of total and export production can strongly influence atmospheric CO2 levels (and hence climate) on geological time scales, as well as set upper bounds for sustainable fisheries harvest. The two fluxes are critically dependent on geophysical processes that determine mixed-layer depth, nutrient fluxes to and within the ocean, and food-web structure. Because the average turnover time of phytoplankton carbon in the ocean is on the order of a week or less, total and export production are extremely sensitive to external forcing and consequently are seldom in steady state. Elucidating the biogeochemical controls and feedbacks on primary production is essential to understanding how oceanic biota responded to and affected natural climatic variability in the geological past, and will respond to anthropogenically influenced changes in coming decades. One of the most crucial feedbacks results from changes in radiative forcing on the hydrological cycle, which influences the aeolian iron flux and, in turn, affects nitrogen fixation and primary production in the oceans.",
    url = "https://doi.org/10.1126/science.281.5374.200",
    doi = "10.1126/science.281.5374.200",
    openalex = "W2105796581",
    references = "doi101029pa005i001p00001, doi101038282677a0, doi101038329408a0, doi101038383495a0, doi101126science166390172, doi101126science2605108640, doi101126science27252651155, doi1015159780691220239, doi1023071930126, doi103354meps010257"
}

For 30 years the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) have been drilling the ocean floors and retrieving sediment cores. This study presents a relational micropaleontological and stratigraphic database, Neptune, where a selection of the published studies made on these sediments is available. The selected sites and their stratigraphic extent represent a statistically reproducible subset of the whole DSDP and ODP data set as of 1995 (up to Leg 135). Cenozoic sediments from 165 globally distributed holes were dated with age/depth plots using biochronology of four marine plankton groups (diatoms, nannofossils, foraminifera, and radiolarians). Each hole's location is available with paleogeographic coordinates. A taxonomic revision of the 8000+ reported species names was also made. The database is searchable and a variety of routines are available. Data can be exported to produce age range charts, geographic distribution maps, and occurrence charts.

@article{doi102687999013,
    author = "Spencer‐Cervato, Cinzia",
    title = "The Cenozoic deep sea microfossil record: Explorations of the DSDP/ODP sample set using the NEPTUNE database",
    year = "1999",
    journal = "Palaeontologia Electronica",
    abstract = "For 30 years the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) have been drilling the ocean floors and retrieving sediment cores. This study presents a relational micropaleontological and stratigraphic database, Neptune, where a selection of the published studies made on these sediments is available. The selected sites and their stratigraphic extent represent a statistically reproducible subset of the whole DSDP and ODP data set as of 1995 (up to Leg 135). Cenozoic sediments from 165 globally distributed holes were dated with age/depth plots using biochronology of four marine plankton groups (diatoms, nannofossils, foraminifera, and radiolarians). Each hole's location is available with paleogeographic coordinates. A taxonomic revision of the 8000+ reported species names was also made. The database is searchable and a variety of routines are available. Data can be exported to produce age range charts, geographic distribution maps, and occurrence charts.",
    url = "https://doi.org/10.26879/99013",
    doi = "10.26879/99013",
    openalex = "W2182763539",
    references = "doi1010160012821x75900862, doi1010160025322771900533, doi1010160198014989900927, doi10102992jb01202, doi10102994jb03098, doi101029pa002i001p00001, doi1011300016760619951071272lncnpi23co2, doi1011300091761319775400gsolqc20co2, doi102973dsdpproc151161973, openalexw2267844404"
}

A deep-sea temperature record for the past 50 million years has been produced from the magnesium/calcium ratio (Mg/Ca) in benthic foraminiferal calcite. The record is strikingly similar in form to the corresponding benthic oxygen isotope (delta(18)O) record and defines an overall cooling of about 12 degrees C in the deep oceans with four main cooling periods. Used in conjunction with the benthic delta(18)O record, the magnesium temperature record indicates that the first major accumulation of Antarctic ice occurred rapidly in the earliest Oligocene (34 million years ago) and was not accompanied by a decrease in deep-sea temperatures.

@article{doi101126science2875451269,
    author = "Lear, Caroline H. and Elderfield, Henry and Wilson, Paul A.",
    title = "Cenozoic Deep-Sea Temperatures and Global Ice Volumes from Mg/Ca in Benthic Foraminiferal Calcite",
    year = "2000",
    journal = "Science",
    abstract = "A deep-sea temperature record for the past 50 million years has been produced from the magnesium/calcium ratio (Mg/Ca) in benthic foraminiferal calcite. The record is strikingly similar in form to the corresponding benthic oxygen isotope (delta(18)O) record and defines an overall cooling of about 12 degrees C in the deep oceans with four main cooling periods. Used in conjunction with the benthic delta(18)O record, the magnesium temperature record indicates that the first major accumulation of Antarctic ice occurred rapidly in the earliest Oligocene (34 million years ago) and was not accompanied by a decrease in deep-sea temperatures.",
    url = "https://doi.org/10.1126/science.287.5451.269",
    doi = "10.1126/science.287.5451.269",
    openalex = "W2157392485",
    references = "doi1010160016703795004467, doi1010160031018294902518, doi101016s0016703797001816, doi10102990jb02015, doi10102993pa03266, doi10102996pa00571, doi101029gm032, doi101029pa002i001p00001, doi10103831447, doi1011300091761319960240279svisca23co2, doi1015159781400862924"
}

@article{openalexw2267844404,
    author = "Binns, R. A. and Barriga, Fernando and Miller, John M. and Asada, Ryuji and Bach, W. and Bartetzko, Anne and Benning, L.G. and Bjerkgård, Terje and Christiansen, Lizet Brokner and Findlay, B. and Iturrino, Gerardo J. and Kimura, Hisanori and Lackschewitz, Klas",
    title = "Proceedings of the Ocean Drilling Program",
    year = "2002",
    openalex = "W2267844404",
    references = "doi1010160016703769901264, doi101016037783988090016x, doi10102994jb03098, doi101086622910, doi101126science23547931156, doi101126science27753341956, doi10113000167606195970115rofpim20co2, doi101144gsjgs14230433, doi101144gslmem19850100115, doi1011639789004616455018, doi101306d42697742b2611d78648000102c1865d, doi102118942054g, doi102973dsdpproc151161973, doi102973dsdpproc291171975, openalexw1533729466, openalexw2727055235, openalexw62718268"
}

In the Earth's geological record massive marine ecological change has been attributed to the occurrence of widespread anoxia in the ocean [Jahren, 2002; White, 2002; Wignall and Twitchett, 1996]. Climate change projection till the end of this century predict a 4 to 7% decline in the dissolve oxygen in the ocean [Bopp et al., 2002; Matear et al., 2000; Plattner et al., 2001; Sarmiento et al., 1998] suggesting the potential for global warming to eventually drive the deep ocean anoxic. To examine the multicentury impact of protracted global warming on oceanic concentrations of dissolved oxygen, we use a climate system model and a low‐order oceanic biogeochemical model. The models are integrated for an atmospheric equivalent CO 2 concentration, which is specified to triple according to a standard scenario from the late nineteenth to the late twenty‐first century, and then is subsequently held constant at that elevated level for an additional 6 centuries. For the present day, the model successfully reproduced the large‐scale features of the dissolved oxygen field in the ocean. In the global warming simulation, the physical model displays marked changes in high‐latitude oceanic stratification and overturning, including near‐cessation of deep water renewal for depths greater than about 1.5 km during the period of elevated stable CO 2 concentration. Our model predicts a decline in oxygen concentration through most of the subsurface ocean. Concentration changes in the thermocline waters result mainly from solubility changes in the upstream source waters, while changes in the deep waters result mainly from lack of ventilation and ongoing consumption of oxygen by remineralization of sinking particulate organic matter. Changes in the upper 2 km of the ocean generally show signs of equilibration by the end of the integration, but at greater depths, there occurs a slow but steady decline through to the end of the integration. By the end of the integration, we simulate a doubling of the volume of hypoxic water (less than 10 μmol/kg) in the thermocline of the eastern equatorial Pacific Ocean. During the integration deep ocean oxygen concentrations generally decline by between 20 and 40%, but, significantly, no extensive deep ocean anoxia develops during the period of integration, nor does it appear that it would likely do so for at least a further 4000 years of integration. Subsurface oxygen decline is moderated by an overall reduction in export production of particulate organic matter, which reduces oxygen consumption in the ocean interior due to the remineralization of this material.

@article{doi1010292002gb001997,
    author = "Matear, Richard J. and Hirst, A. C.",
    title = "Long‐term changes in dissolved oxygen concentrations in the ocean caused by protracted global warming",
    year = "2003",
    journal = "Global Biogeochemical Cycles",
    abstract = "In the Earth's geological record massive marine ecological change has been attributed to the occurrence of widespread anoxia in the ocean [Jahren, 2002; White, 2002; Wignall and Twitchett, 1996]. Climate change projection till the end of this century predict a 4 to 7\% decline in the dissolve oxygen in the ocean [Bopp et al., 2002; Matear et al., 2000; Plattner et al., 2001; Sarmiento et al., 1998] suggesting the potential for global warming to eventually drive the deep ocean anoxic. To examine the multicentury impact of protracted global warming on oceanic concentrations of dissolved oxygen, we use a climate system model and a low‐order oceanic biogeochemical model. The models are integrated for an atmospheric equivalent CO 2 concentration, which is specified to triple according to a standard scenario from the late nineteenth to the late twenty‐first century, and then is subsequently held constant at that elevated level for an additional 6 centuries. For the present day, the model successfully reproduced the large‐scale features of the dissolved oxygen field in the ocean. In the global warming simulation, the physical model displays marked changes in high‐latitude oceanic stratification and overturning, including near‐cessation of deep water renewal for depths greater than about 1.5 km during the period of elevated stable CO 2 concentration. Our model predicts a decline in oxygen concentration through most of the subsurface ocean. Concentration changes in the thermocline waters result mainly from solubility changes in the upstream source waters, while changes in the deep waters result mainly from lack of ventilation and ongoing consumption of oxygen by remineralization of sinking particulate organic matter. Changes in the upper 2 km of the ocean generally show signs of equilibration by the end of the integration, but at greater depths, there occurs a slow but steady decline through to the end of the integration. By the end of the integration, we simulate a doubling of the volume of hypoxic water (less than 10 μmol/kg) in the thermocline of the eastern equatorial Pacific Ocean. During the integration deep ocean oxygen concentrations generally decline by between 20 and 40\%, but, significantly, no extensive deep ocean anoxia develops during the period of integration, nor does it appear that it would likely do so for at least a further 4000 years of integration. Subsurface oxygen decline is moderated by an overall reduction in export production of particulate organic matter, which reduces oxygen consumption in the ocean interior due to the remineralization of this material.",
    url = "https://doi.org/10.1029/2002gb001997",
    doi = "10.1029/2002gb001997",
    openalex = "W1980823401",
    references = "doi101016s0146638000001613, doi101098rsta20021097"
}

In this paper, we present an equilibrium thermodynamic model to accurately predict the maximum depth of hydrate stability in the seafloor, including the effects of water salinity, hydrate confinement in pores, and the distribution of pore sizes in natural sediments. This model uses sediment type, geothermal gradient, and seafloor depth as input to predict the thickness of the hydrate zone. Using this hydrate model and a mass-transfer description for hydrate formation, we have also developed a predictive method for the occurrence of methane hydrates in the ocean. Based on this information, a prediction for the distribution of methane hydrate in ocean sediment is presented on a 1° latitude by 1° longitude (1° × 1°) global grid. From this detailed prediction, we estimate that there is a total volume of 1.2 × 1017 m3 of methane gas (expanded to atmospheric conditions), or, equivalently, 74 400 Gt of CH4 in ocean hydrates, which is 3 orders of magnitude larger than worldwide conventional natural gas reserves. Of this number, we estimate that 4.4 × 1016 m3 of methane expanded to standard temperature and pressure (STP) exists on the continental margins.

@article{doi101021ef049798o,
    author = "Klauda, Jeffery B. and Sandler, Stanley I.",
    title = "Global Distribution of Methane Hydrate in Ocean Sediment",
    year = "2005",
    journal = "Energy \& Fuels",
    abstract = "In this paper, we present an equilibrium thermodynamic model to accurately predict the maximum depth of hydrate stability in the seafloor, including the effects of water salinity, hydrate confinement in pores, and the distribution of pore sizes in natural sediments. This model uses sediment type, geothermal gradient, and seafloor depth as input to predict the thickness of the hydrate zone. Using this hydrate model and a mass-transfer description for hydrate formation, we have also developed a predictive method for the occurrence of methane hydrates in the ocean. Based on this information, a prediction for the distribution of methane hydrate in ocean sediment is presented on a 1° latitude by 1° longitude (1° × 1°) global grid. From this detailed prediction, we estimate that there is a total volume of 1.2 × 1017 m3 of methane gas (expanded to atmospheric conditions), or, equivalently, 74 400 Gt of CH4 in ocean hydrates, which is 3 orders of magnitude larger than worldwide conventional natural gas reserves. Of this number, we estimate that 4.4 × 1016 m3 of methane expanded to standard temperature and pressure (STP) exists on the continental margins.",
    url = "https://doi.org/10.1021/ef049798o",
    doi = "10.1021/ef049798o",
    openalex = "W2092960018",
    references = "doi1010291999jb900175, doi10102994gb00766"
}

@article{doi101038nature03135,
    author = "Coxall, Helen K. and Wilson, Paul A. and Pälike, Heiko and Lear, Caroline H. and Backman, Jan",
    title = "Rapid stepwise onset of Antarctic glaciation and deeper calcite compensation in the Pacific Ocean",
    year = "2005",
    journal = "Nature",
    url = "https://doi.org/10.1038/nature03135",
    doi = "10.1038/nature03135",
    openalex = "W2058410188",
    references = "doi1010160012821x75900862, doi101016jicarus200404005, doi101016s0277379101000828, doi1010292000jb900449, doi10102990jb02015, doi10102996pa00571, doi10103835038000, doi101038367260a0, doi101038nature01290, doi101126science2875451269"
}

The environmental conditions of Earth, including the climate, are determined by physical, chemical, biological, and human interactions that transform and transport materials and energy. This is the "Earth system": a highly complex entity characterized by multiple nonlinear responses and thresholds, with linkages between disparate components. One important part of this system is the iron cycle, in which iron-containing soil dust is transported from land through the atmosphere to the oceans, affecting ocean biogeochemistry and hence having feedback effects on climate and dust production. Here we review the key components of this cycle, identifying critical uncertainties and priorities for future research.

@article{doi101126science1105959,
    author = "Jickells, T. D. and An, Zhisheng and Andersen, K. K. and Baker, Alex R. and Bergametti, G. and Brooks, Nick and Cao, Junji and Boyd, Philip W. and Duce, Robert A. and Hunter, Keith A. and Kawahata, Hodaka and Kubilay, N. and LaRoche, Julie and Liss, Peter S. and Mahowald, N. M. and Prospero, Joseph M. and Ridgwell, Andy and Tegen, Ina and Torres, Rodrigo",
    title = "Global Iron Connections Between Desert Dust, Ocean Biogeochemistry, and Climate",
    year = "2005",
    journal = "Science",
    abstract = {The environmental conditions of Earth, including the climate, are determined by physical, chemical, biological, and human interactions that transform and transport materials and energy. This is the "Earth system": a highly complex entity characterized by multiple nonlinear responses and thresholds, with linkages between disparate components. One important part of this system is the iron cycle, in which iron-containing soil dust is transported from land through the atmosphere to the oceans, affecting ocean biogeochemistry and hence having feedback effects on climate and dust production. Here we review the key components of this cycle, identifying critical uncertainties and priorities for future research.},
    url = "https://doi.org/10.1126/science.1105959",
    doi = "10.1126/science.1105959",
    openalex = "W2170312901",
    references = "doi10102993rg03257, doi101029pa005i001p00001, doi101126science1083545"
}

Centennial climate variability over the last ice age exhibits clear bipolar behavior. High-resolution analyses of marine sediment cores from the Iberian margin trace a number of associated changes simultaneously. Proxies of sea surface temperature and water mass distribution, as well as relative biomarker content, demonstrate that this typical north-south coupling was pervasive for the cold phases of climate during the past 420,000 years. Cold episodes after relatively warm and largely ice-free periods occurred when the predominance of deep water formation changed from northern to southern sources. These results reinforce the connection between rapid climate changes at Mediterranean latitudes and century-to-millennial variability in northern and southern polar regions.

@article{doi101126science1139994,
    author = "Martrat, Belén and Grimalt, Joan O. and Shackleton, Nicholas J and de Abreu, Lúcia and Hutterli, M. A. and Stocker, Thomas F.",
    title = "Four Climate Cycles of Recurring Deep and Surface Water Destabilizations on the Iberian Margin",
    year = "2007",
    journal = "Science",
    abstract = "Centennial climate variability over the last ice age exhibits clear bipolar behavior. High-resolution analyses of marine sediment cores from the Iberian margin trace a number of associated changes simultaneously. Proxies of sea surface temperature and water mass distribution, as well as relative biomarker content, demonstrate that this typical north-south coupling was pervasive for the cold phases of climate during the past 420,000 years. Cold episodes after relatively warm and largely ice-free periods occurred when the predominance of deep water formation changed from northern to southern sources. These results reinforce the connection between rapid climate changes at Mediterranean latitudes and century-to-millennial variability in northern and southern polar regions.",
    url = "https://doi.org/10.1126/science.1139994",
    doi = "10.1126/science.1139994",
    openalex = "W1978347718",
    references = "doi101038nature02786"
}

Abstract. Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.

@article{doi105194bg68352009,
    author = "Gutiérrez, Dimitri and Sifeddine, Abdelfettah and Field, David and Ortlieb, Luc and Vargas, Gabriel and Chávez, Francisco P. and Velazco, Federico and Ferreira, José and Tapia, Pedro M. and Salvatteci, Renato and Boucher, H. and Morales, M. C. and Valdés, Jorge and Reyss, Jean‐Louis and Campusano, A. and Boussafir, Mohammed and Mandeng-Yogo, M. and da Glória Motta Garcia, Maria and Baumgartner, T.",
    title = "Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age",
    year = "2008",
    journal = "Biogeosciences",
    abstract = "Abstract. Climate and ocean ecosystem variability has been well recognized during the twentieth century but it is unclear if modern ocean biogeochemistry is susceptible to the large, abrupt shifts that characterized the Late Quaternary. Time series from marine sediments off Peru show an abrupt centennial-scale biogeochemical regime shift in the early nineteenth century, of much greater magnitude and duration than present day multi-decadal variability. A rapid expansion of the subsurface nutrient-rich, oxygen-depleted waters resulted in higher biological productivity, including pelagic fish. The shift was likely driven by a northward migration of the Intertropical Convergence Zone and the South Pacific Subtropical High to their present day locations, coupled with a strengthening of Walker circulation, towards the end of the Little Ice Age. These findings reveal the potential for large reorganizations in tropical Pacific climate with immediate effects on ocean biogeochemical cycling and ecosystem structure.",
    url = "https://doi.org/10.5194/bg-6-835-2009",
    doi = "10.5194/bg-6-835-2009",
    openalex = "W2139190105",
    references = "doi101016jorggeochem200402009"
}

A prominent, middle Miocene (17.5–13.5 Ma) carbon isotope excursion ubiquitously recorded in carbonate sediments has been attributed to enhanced marine productivity and sequestration of 13 C depleted organic carbon in marine sediments or enhanced carbon burial in peat/lignite deposits on land. Here we test the hypothesis that the marine δ 13 C record reflects a change in productivity with proxy records from three Atlantic Ocean sites (Deep Sea Drilling Program Site 608 and Ocean Drilling Program Sites 925 and 1265). Our multiproxy approach is based on benthic foraminiferal accumulation rates, elemental ratios (Ba/Al and P/Al), the δ 13 C of bulk sedimentary organic matter, and dissolution indices. We compare these proxies to benthic foraminiferal δ 13 C values measured on the same samples. Our results indicate that marine paleoproductivity in the Atlantic Ocean is not related to the benthic foraminiferal δ 13 C excursion. A numerical box model confirms that marine productivity cannot account for the δ 13 C maximum. The model shows that sequestration of 1.5 × 10 18 mol C in the terrestrial realm over a period of 3 Ma leads to a 0.9‰ δ 13 C increase in the deep ocean, which is near the observed records. Therefore, an increase in continental organic carbon sequestration is the most plausible way to enrich the ocean's carbon pool with 13 C, which is consistent with coeval lignite deposits worldwide. The δ 13 C values of bulk sedimentary organic matter parallel the δ 13 C of dissolved inorganic carbon as reflected by benthic foraminiferal δ 13 C values suggesting no significant change in atmospheric p CO 2 levels over the investigated period.

@article{doi1010292008pa001605,
    author = "Diester‐Haass, L. and Billups, Katharina and Gröcke, Darren R. and François, Louis and Lefèbvre, Vincent and Emeis, Kay‐Christian",
    title = "Mid‐Miocene paleoproductivity in the Atlantic Ocean and implications for the global carbon cycle",
    year = "2009",
    journal = "Paleoceanography",
    abstract = "A prominent, middle Miocene (17.5–13.5 Ma) carbon isotope excursion ubiquitously recorded in carbonate sediments has been attributed to enhanced marine productivity and sequestration of 13 C depleted organic carbon in marine sediments or enhanced carbon burial in peat/lignite deposits on land. Here we test the hypothesis that the marine δ 13 C record reflects a change in productivity with proxy records from three Atlantic Ocean sites (Deep Sea Drilling Program Site 608 and Ocean Drilling Program Sites 925 and 1265). Our multiproxy approach is based on benthic foraminiferal accumulation rates, elemental ratios (Ba/Al and P/Al), the δ 13 C of bulk sedimentary organic matter, and dissolution indices. We compare these proxies to benthic foraminiferal δ 13 C values measured on the same samples. Our results indicate that marine paleoproductivity in the Atlantic Ocean is not related to the benthic foraminiferal δ 13 C excursion. A numerical box model confirms that marine productivity cannot account for the δ 13 C maximum. The model shows that sequestration of 1.5 × 10 18 mol C in the terrestrial realm over a period of 3 Ma leads to a 0.9‰ δ 13 C increase in the deep ocean, which is near the observed records. Therefore, an increase in continental organic carbon sequestration is the most plausible way to enrich the ocean's carbon pool with 13 C, which is consistent with coeval lignite deposits worldwide. The δ 13 C values of bulk sedimentary organic matter parallel the δ 13 C of dissolved inorganic carbon as reflected by benthic foraminiferal δ 13 C values suggesting no significant change in atmospheric p CO 2 levels over the investigated period.",
    url = "https://doi.org/10.1029/2008pa001605",
    doi = "10.1029/2008pa001605",
    openalex = "W1621753227",
    references = "doi101306080701720252"
}

This chapter contains sections titled: Introducion Stratigraphy of the Indian Ocean and its Marginal Basins Oceanic Plateau and Outer Continental Shelf Sites Mid-and Late Cretaceous History by Stage Summary

@incollection{doi101029gm070p0225,
    author = "Holmes, Mary Anne and Watkins, David K.",
    title = "Middle and Late Cretaceous History of the Indian Ocean",
    year = "2011",
    booktitle = "Geophysical monograph",
    abstract = "This chapter contains sections titled: Introducion Stratigraphy of the Indian Ocean and its Marginal Basins Oceanic Plateau and Outer Continental Shelf Sites Mid-and Late Cretaceous History by Stage Summary",
    url = "https://doi.org/10.1029/gm070p0225",
    doi = "10.1029/gm070p0225",
    openalex = "W1501796423",
    references = "doi102973dsdpproc251341974"
}

The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life--SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO(2) and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO(2) and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods.

@article{doi101371journalpone0022588,
    author = "Ramírez-Llodra, Eva and Tyler, Paul A. and Baker, Maria and Bergstad, Odd Aksel and Clark, Malcolm R. and Escobar‐Briones, Elva and Levin, Lisa A. and Menot, Lénàïck and Rowden, Ashley A. and Smith, Craig R. and Dover, Cindy Lee Van",
    title = "Man and the Last Great Wilderness: Human Impact on the Deep Sea",
    year = "2011",
    journal = "PLoS ONE",
    abstract = "The deep sea, the largest ecosystem on Earth and one of the least studied, harbours high biodiversity and provides a wealth of resources. Although humans have used the oceans for millennia, technological developments now allow exploitation of fisheries resources, hydrocarbons and minerals below 2000 m depth. The remoteness of the deep seafloor has promoted the disposal of residues and litter. Ocean acidification and climate change now bring a new dimension of global effects. Thus the challenges facing the deep sea are large and accelerating, providing a new imperative for the science community, industry and national and international organizations to work together to develop successful exploitation management and conservation of the deep-sea ecosystem. This paper provides scientific expert judgement and a semi-quantitative analysis of past, present and future impacts of human-related activities on global deep-sea habitats within three categories: disposal, exploitation and climate change. The analysis is the result of a Census of Marine Life--SYNDEEP workshop (September 2008). A detailed review of known impacts and their effects is provided. The analysis shows how, in recent decades, the most significant anthropogenic activities that affect the deep sea have evolved from mainly disposal (past) to exploitation (present). We predict that from now and into the future, increases in atmospheric CO(2) and facets and consequences of climate change will have the most impact on deep-sea habitats and their fauna. Synergies between different anthropogenic pressures and associated effects are discussed, indicating that most synergies are related to increased atmospheric CO(2) and climate change effects. We identify deep-sea ecosystems we believe are at higher risk from human impacts in the near future: benthic communities on sedimentary upper slopes, cold-water corals, canyon benthic communities and seamount pelagic and benthic communities. We finalise this review with a short discussion on protection and management methods.",
    url = "https://doi.org/10.1371/journal.pone.0022588",
    doi = "10.1371/journal.pone.0022588",
    openalex = "W2019284478",
    references = "doi101002j147786961990tb05660x, doi10102994gb00766, doi101038nature04095, doi101098rstb20080205, doi101126science1094559, doi101126science1097403, doi101126science1149345, doi101126science18040931377, doi101126science2264677965, doi101146annurevmarine010908163834, doi1015159780691239477, doi105194bg616712009, doi105860choice380926, nardin1979a, openalexw1548396839, openalexw2939474406, openalexw617039848"
}

Abstract The environmental conditions and reaction paths of shallow-water glauconitization (<500 m water depth, ~15°C) close to the sediment-seawater interface are generally considered to be well understood. In contrast, the key factors controlling deep-sea glauconite formation are still poorly constrained. In the present study, green grains formed in the recent deep-sea environment of the ODP Site 959, Ivory Coast-Ghana Marginal Ridge, (~2100 m water depth, 3-6°C) were investigated by X-ray diffraction and electron microscopic methods in order to determine the rate and mechanism of glauconitization. Green clay authigenesis at Hole 959C occurred mainly in the tests of calcareous foraminifera which provided post-depositional conditions ideal for glauconitization. Within this organic-rich microenvironment, Fe-smectite developed <10 ky after deposition of the sediments by precipitation from precursor gels containing Fe, Mg, Al, and silica. This gel formation was supported by microbial activity and cation supply from the interstitial solution by diffusion. At a later stage of early marine diagenesis (900 ky), the Fe-smectites reacted to form mixed-layer glauconite-smectite. Further down (~2500 ky), almost pure glauconite with no compositional gaps between the Fe-smectite and glauconite end members formed. This burial-related Fe-smectite-to-glauconite reaction indicates that the glauconitization process was controlled mainly by the chemistry of the interstitial solutions. The composition of the interstitial solution depends heavily on micro-environmental changes related to early diagenetic oxidation of biodegradable (marine) organic matter, microbial sulfate reduction, silicate mineral alteration, carbonate dissolution, and Fe redox reactions. The availability of Fe is suggested as the probable limiting factor for glauconitization, explaining the various states of green-grain maturity within the samples, and this cation may be the most important rate-determining element. The rate of glauconite formation at ODP Site 959 is given by %Gl Sed = 22.6·log(age Sed) + 1.6 (R 2 = 0.97) where %Gl Sed is the state of glauconitization in the sediment and age Sed is the sediment age (in ky). This glauconitization rate depends mainly on continuous cation supply (in particular Fe) and is about five times less than that in shallow-shelf regions, suggesting significantly slower reaction at the lower temperature of deep-sea environments.

@article{doi101346ccmn20130610307,
    author = "Baldermann, Andre and Warr, Laurence N. and Grathoff, Georg and Dietzel, Martin",
    title = "The Rate and Mechanism of Deep-Sea Glauconite Formation at the Ivory Coast-Ghana Marginal Ridge",
    year = "2013",
    journal = "Clays and Clay Minerals",
    abstract = "Abstract The environmental conditions and reaction paths of shallow-water glauconitization (<500 m water depth, \textasciitilde 15°C) close to the sediment-seawater interface are generally considered to be well understood. In contrast, the key factors controlling deep-sea glauconite formation are still poorly constrained. In the present study, green grains formed in the recent deep-sea environment of the ODP Site 959, Ivory Coast-Ghana Marginal Ridge, (\textasciitilde 2100 m water depth, 3-6°C) were investigated by X-ray diffraction and electron microscopic methods in order to determine the rate and mechanism of glauconitization. Green clay authigenesis at Hole 959C occurred mainly in the tests of calcareous foraminifera which provided post-depositional conditions ideal for glauconitization. Within this organic-rich microenvironment, Fe-smectite developed <10 ky after deposition of the sediments by precipitation from precursor gels containing Fe, Mg, Al, and silica. This gel formation was supported by microbial activity and cation supply from the interstitial solution by diffusion. At a later stage of early marine diagenesis (900 ky), the Fe-smectites reacted to form mixed-layer glauconite-smectite. Further down (\textasciitilde 2500 ky), almost pure glauconite with no compositional gaps between the Fe-smectite and glauconite end members formed. This burial-related Fe-smectite-to-glauconite reaction indicates that the glauconitization process was controlled mainly by the chemistry of the interstitial solutions. The composition of the interstitial solution depends heavily on micro-environmental changes related to early diagenetic oxidation of biodegradable (marine) organic matter, microbial sulfate reduction, silicate mineral alteration, carbonate dissolution, and Fe redox reactions. The availability of Fe is suggested as the probable limiting factor for glauconitization, explaining the various states of green-grain maturity within the samples, and this cation may be the most important rate-determining element. The rate of glauconite formation at ODP Site 959 is given by \%Gl Sed = 22.6·log(age Sed) + 1.6 (R 2 = 0.97) where \%Gl Sed is the state of glauconitization in the sediment and age Sed is the sediment age (in ky). This glauconitization rate depends mainly on continuous cation supply (in particular Fe) and is about five times less than that in shallow-shelf regions, suggesting significantly slower reaction at the lower temperature of deep-sea environments.",
    url = "https://doi.org/10.1346/ccmn.2013.0610307",
    doi = "10.1346/ccmn.2013.0610307",
    openalex = "W2326459227",
    references = "doi102973odpprocsr1590181998"
}

We analyze the density distribution of marine sediments using density samples taken from 716 drill sites of the Deep Sea Drilling Project (DSDP). The samples taken within the upper stratigraphic layer exhibit a prevailing trend of the decreasing density with the increasing ocean depth (at a rate of -0.05 g/cm(3) per 1 km). Our results confirm findings of published studies that the density nonlinearly increases with the increasing sediment depth due to compaction. We further establish a 3D density model of marine sediments and propose theoretical models of the ocean-sediment and sediment-bedrock density contrasts. The sediment density-depth equation approximates density samples with an average uncertainty of about 10% and better represents the density distribution especially at deeper sections of basin sediments than a uniform density model. The analysis of DSDP density data also reveals that the average density of marine sediments is 1.70 g/cm(3) and the average density of the ocean bedrock is 2.9 g/cm(3).

@article{doi1011552014823296,
    author = "Tenzer, Róbert and Gladkikh, Vladislav",
    title = "Assessment of Density Variations of Marine Sediments with Ocean and Sediment Depths",
    year = "2014",
    journal = "The Scientific World JOURNAL",
    abstract = "We analyze the density distribution of marine sediments using density samples taken from 716 drill sites of the Deep Sea Drilling Project (DSDP). The samples taken within the upper stratigraphic layer exhibit a prevailing trend of the decreasing density with the increasing ocean depth (at a rate of -0.05 g/cm(3) per 1 km). Our results confirm findings of published studies that the density nonlinearly increases with the increasing sediment depth due to compaction. We further establish a 3D density model of marine sediments and propose theoretical models of the ocean-sediment and sediment-bedrock density contrasts. The sediment density-depth equation approximates density samples with an average uncertainty of about 10\% and better represents the density distribution especially at deeper sections of basin sediments than a uniform density model. The analysis of DSDP density data also reveals that the average density of marine sediments is 1.70 g/cm(3) and the average density of the ocean bedrock is 2.9 g/cm(3).",
    url = "https://doi.org/10.1155/2014/823296",
    doi = "10.1155/2014/823296",
    openalex = "W2075115075",
    references = "doi101007s0002401102755, doi101029jb082i005p00803, doi101029jb083ib09p04485, doi101029jb085ib07p03711, doi101038311555a0, doi101111j136524781987tb00858x, doi101306212f6f3c2b2411d78648000102c1865d, doi1013063d93289e16b111d78645000102c1865d, doi107289v5nz85mt, openalexw2883478268"
}

"The oceanographic databases described by this atlas series expands on the World Ocean Database 2009 (WOD09) product and its predecessors. We have expanded by including substantial amounts of both recent and historical data not previously available. Earlier NODC/WDC oceanographic databases, and products derived from these databases, have proven to be of great utility to the international oceanographic, climate research, and operational environmental forecasting communities. In particular, the objectively analyzed fields of temperature and salinity derived from these databases have been used in a variety of ways. These include use as boundary and/or initial conditions in numerical ocean circulation models, verification of numerical simulations of the ocean, as a form of 'sea truth' for satellite measurements such as altimetric observations of sea surface height among others. Increasingly, nutrient fields are being used to initialize and/or verify biogeochemical models of the world ocean. In addition, NODC/WDC products are critical for support of international assessment programs such as the Intergovernmental Program on Climate Change (IPCC) of the United Nations"--Introduction.

@article{doi107289v5nz85mt,
    author = "Boyer, Timothy P. and Antonov, John I. and Baranova, O and Garcia, Hernan E. and Johnson, Daphne R. and Mishonov, Alexey and O’Brien, Todd and Seidov, Dan and Smolyar, I and Zweng, M. and Paver, Christopher R. and Locarnini, Ricardo A. and Reagan, James R. and Coleman, Carla and Grodsky, Alexandra",
    title = "World ocean database 2013.",
    year = "2014",
    journal = "NOAA Institutional Repository",
    abstract = {"The oceanographic databases described by this atlas series expands on the World Ocean Database 2009 (WOD09) product and its predecessors. We have expanded by including substantial amounts of both recent and historical data not previously available. Earlier NODC/WDC oceanographic databases, and products derived from these databases, have proven to be of great utility to the international oceanographic, climate research, and operational environmental forecasting communities. In particular, the objectively analyzed fields of temperature and salinity derived from these databases have been used in a variety of ways. These include use as boundary and/or initial conditions in numerical ocean circulation models, verification of numerical simulations of the ocean, as a form of 'sea truth' for satellite measurements such as altimetric observations of sea surface height among others. Increasingly, nutrient fields are being used to initialize and/or verify biogeochemical models of the world ocean. In addition, NODC/WDC products are critical for support of international assessment programs such as the Intergovernmental Program on Climate Change (IPCC) of the United Nations"--Introduction.},
    url = "https://doi.org/10.7289/v5nz85mt",
    doi = "10.7289/v5nz85mt",
    openalex = "W2910614665"
}

Abstract Macroalgae drive the largest CO 2 flux fixed globally by marine macrophytes. Most of the resulting biomass is exported through the coastal ocean as detritus and yet almost no field measurements have verified its potential net sequestration in marine sediments. This gap limits the scope for the inclusion of macroalgae within blue carbon schemes that support ocean carbon sequestration globally, and the understanding of the role their carbon plays within distal food webs. Here, we pursued three lines of evidence (eDNA sequencing, Bayesian Stable Isotope Mixing Modeling, and benthic‐pelagic process measurements) to generate needed, novel data addressing this gap. To this end, a 13‐month study was undertaken at a deep coastal sedimentary site in the English Channel, and the surrounding shoreline of Plymouth, UK. The eDNA sequencing indicated that detritus from most macroalgae in surrounding shores occurs within deep, coastal sediments, with detritus supply reflecting the seasonal ecology of individual species. Bayesian stable isotope mixing modeling [C and N] highlighted its vital role in supporting the deep coastal benthic food web (22–36% of diets), especially when other resources are seasonally low. The magnitude of detritus uptake within the food web and sediments varies seasonally, with an average net sedimentary organic macroalgal carbon sequestration of 8.75 g C·m −2 ·yr −1. The average net sequestration of particulate organic carbon in sediments is 58.74 g C·m −2 ·yr −1, the two rates corresponding to 4–5% and 26–37% of those associated with mangroves, salt marshes, and seagrass beds, systems more readily identified as blue carbon habitats. These novel data provide important first estimates that help to contextualize the importance of macroalgal‐sedimentary connectivity for deep coastal food webs, and measured fluxes help constrain its role within global blue carbon that can support policy development. At a time when climate change mitigation is at the foreground of environmental policy development, embracing the full potential of the ocean in supporting climate regulation via CO 2 sequestration is a necessity.

@article{doi101002ecm1366,
    author = "Queirós, Ana M. and Stephens, Nicholas and Widdicombe, Stephen and Tait, Karen and McCoy, Sophie J. and Ingels, Jeroen and Rühl, Saskia and Airs, Ruth L. and Beesley, Amanda and Carnovale, Giorgia and Cazenave, Pierre and Dashfield, Sarah and Er, Hua and Jones, Mark R. and Lindeque, Penelope K. and McNeill, Caroline Louise and Nunes, Joana and Parry, Helen and Pascoe, Christine and Widdicombe, Claire E. and Smyth, Tim and Atkinson, Angus and Krause‐Jensen, Dorte and Somerfield, Paul J.",
    title = "Connected macroalgal‐sediment systems: blue carbon and food webs in the deep coastal ocean",
    year = "2019",
    journal = "Ecological Monographs",
    abstract = "Abstract Macroalgae drive the largest CO 2 flux fixed globally by marine macrophytes. Most of the resulting biomass is exported through the coastal ocean as detritus and yet almost no field measurements have verified its potential net sequestration in marine sediments. This gap limits the scope for the inclusion of macroalgae within blue carbon schemes that support ocean carbon sequestration globally, and the understanding of the role their carbon plays within distal food webs. Here, we pursued three lines of evidence (eDNA sequencing, Bayesian Stable Isotope Mixing Modeling, and benthic‐pelagic process measurements) to generate needed, novel data addressing this gap. To this end, a 13‐month study was undertaken at a deep coastal sedimentary site in the English Channel, and the surrounding shoreline of Plymouth, UK. The eDNA sequencing indicated that detritus from most macroalgae in surrounding shores occurs within deep, coastal sediments, with detritus supply reflecting the seasonal ecology of individual species. Bayesian stable isotope mixing modeling [C and N] highlighted its vital role in supporting the deep coastal benthic food web (22–36\% of diets), especially when other resources are seasonally low. The magnitude of detritus uptake within the food web and sediments varies seasonally, with an average net sedimentary organic macroalgal carbon sequestration of 8.75 g C·m −2 ·yr −1. The average net sequestration of particulate organic carbon in sediments is 58.74 g C·m −2 ·yr −1, the two rates corresponding to 4–5\% and 26–37\% of those associated with mangroves, salt marshes, and seagrass beds, systems more readily identified as blue carbon habitats. These novel data provide important first estimates that help to contextualize the importance of macroalgal‐sedimentary connectivity for deep coastal food webs, and measured fluxes help constrain its role within global blue carbon that can support policy development. At a time when climate change mitigation is at the foreground of environmental policy development, embracing the full potential of the ocean in supporting climate regulation via CO 2 sequestration is a necessity.",
    url = "https://doi.org/10.1002/ecm.1366",
    doi = "10.1002/ecm.1366",
    openalex = "W2945912522",
    references = "doi1011552014823296"
}

OPE mass of 4100 tonnes with >99% of the OPE inventory estimated to be in the water column. These results highlight the importance of OPEs as water-based Arctic contaminants subject to long-range transport and local sources. The high OPE inventory in the water column of the Canadian Arctic Ocean points to the need for international regulatory mechanisms for persistent and mobile organic contaminants (PMOCs) that are not covered by the risk assessment criteria of the Stockholm Convention.

@article{doi101021acsest0c04422,
    author = "Sühring, Roxana and Diamond, Miriam L. and Bernstein, Sarah N. and Adams, Jennifer and Schuster, Jasmin K. and Fernie, Kim J. and Elliott, Kyle H. and Stern, Gary A. and Jantunen, Liisa M.",
    title = "Organophosphate Esters in the Canadian Arctic Ocean",
    year = "2020",
    journal = "Environmental Science \& Technology",
    abstract = "OPE mass of 4100 tonnes with >99\% of the OPE inventory estimated to be in the water column. These results highlight the importance of OPEs as water-based Arctic contaminants subject to long-range transport and local sources. The high OPE inventory in the water column of the Canadian Arctic Ocean points to the need for international regulatory mechanisms for persistent and mobile organic contaminants (PMOCs) that are not covered by the risk assessment criteria of the Stockholm Convention.",
    url = "https://doi.org/10.1021/acs.est.0c04422",
    doi = "10.1021/acs.est.0c04422",
    openalex = "W3111621955",
    references = "doi1011552014823296"
}

Abstract Despite numerous efforts to properly differentiate between contourites and other deep‐water deposits in cores and outcrops, reliable diagnostic criteria are still lacking. The co‐occurrence of downslope and along‐slope sedimentary processes makes it particularly difficult to differentiate these relatively homogeneous deposits. The main aim of this paper is to identify differences in deep‐water sediments based on Principal Component Analysis of grain size and geochemistry, sedimentary facies, and reinforced by microfacies and ichnofacies. The sediments studied were obtained from two International Ocean Drilling Program Expedition 339 sites in mounded and sheeted drifts in the Gulf of Cadiz. The statistical approach led to the discernment of hemipelagites, silty contourites, sandy contourites, bottom current reworked sands, fine‐grained turbidites and debrites over a range of depositional and physiographic elements. These elements are linked to contourite drifts, the drift‐channel transition, the contourite channel and distal upper slope. When bottom currents or gravity‐driven flows are not the dominant depositional process, marine productivity and continental input settling forms the main depositional mechanism in deep‐water environments. This is reflected by a high variability of the first principal component in hemipelagic deposits. The stacked principal component variability of these deposits evidences that the contourite drift and the adjacent contourite channel were influenced by the interrelation of hemipelagic, gravitational and bottom current induced depositional processes. This interrelation questions the paradigm that a drift is made up solely of muddy sediments. The interrelation of sedimentary processes is a consequence of the precession‐driven changes in the intensity of the Mediterranean Outflow Water related to Mediterranean climate variability, which are punctuated by millennial‐scale variability. Associated vertical and lateral shifts of the Mediterranean Outflow Water, and therefore of its interface with the East North Atlantic Central Water, controlled sediment input and favoured turbulent sediment transport in the middle slope. During the interglacial precession maxima/insolation minima, a more vigorous upper core of the Mediterranean Outflow Water and the enhanced impact of the East North Atlantic Central Water – Mediterranean Outflow Water interface allowed for the development of the sandier contourite deposits.

@article{doi101111sed12813,
    author = "Castro, S. De and Hernández‐Molina, F. Javier and de Weger, Wouter and Jiménez-Espejo, F.J. and Rodrı́guez-Tovar, Francisco J. and Mena, Anxo and Llave, Estefanía and Sierro, Francisco Javier",
    title = "Contourite characterization and its discrimination from other deep‐water deposits in the Gulf of Cadiz contourite depositional system",
    year = "2020",
    journal = "Sedimentology",
    abstract = "Abstract Despite numerous efforts to properly differentiate between contourites and other deep‐water deposits in cores and outcrops, reliable diagnostic criteria are still lacking. The co‐occurrence of downslope and along‐slope sedimentary processes makes it particularly difficult to differentiate these relatively homogeneous deposits. The main aim of this paper is to identify differences in deep‐water sediments based on Principal Component Analysis of grain size and geochemistry, sedimentary facies, and reinforced by microfacies and ichnofacies. The sediments studied were obtained from two International Ocean Drilling Program Expedition 339 sites in mounded and sheeted drifts in the Gulf of Cadiz. The statistical approach led to the discernment of hemipelagites, silty contourites, sandy contourites, bottom current reworked sands, fine‐grained turbidites and debrites over a range of depositional and physiographic elements. These elements are linked to contourite drifts, the drift‐channel transition, the contourite channel and distal upper slope. When bottom currents or gravity‐driven flows are not the dominant depositional process, marine productivity and continental input settling forms the main depositional mechanism in deep‐water environments. This is reflected by a high variability of the first principal component in hemipelagic deposits. The stacked principal component variability of these deposits evidences that the contourite drift and the adjacent contourite channel were influenced by the interrelation of hemipelagic, gravitational and bottom current induced depositional processes. This interrelation questions the paradigm that a drift is made up solely of muddy sediments. The interrelation of sedimentary processes is a consequence of the precession‐driven changes in the intensity of the Mediterranean Outflow Water related to Mediterranean climate variability, which are punctuated by millennial‐scale variability. Associated vertical and lateral shifts of the Mediterranean Outflow Water, and therefore of its interface with the East North Atlantic Central Water, controlled sediment input and favoured turbulent sediment transport in the middle slope. During the interglacial precession maxima/insolation minima, a more vigorous upper core of the Mediterranean Outflow Water and the enhanced impact of the East North Atlantic Central Water – Mediterranean Outflow Water interface allowed for the development of the sandier contourite deposits.",
    url = "https://doi.org/10.1111/sed.12813",
    doi = "10.1111/sed.12813",
    openalex = "W3094434723",
    references = "doi101016jgloplacha201508015, doi103390geosciences10020068"
}

Interest in understanding the extent of plastic and specifically microplastic pollution has increased on a global scale. Still one large piece of the overall puzzle currently lacks: how much plastic pollution has found its way into the deeper areas of the world’s oceans? The extent of microplastic pollution in deep-sea sediments remains poorly quantified, but this knowledge is imperative for predicting the distribution and potential impacts of global plastic pollution. We quantified microplastics in deep-sea sediments from the Great Australian Bight using an adapted density separation and dye fluorescence technique. We analyzed sediment cores from six locations ranging in ocean depths from 1,655 to 3,062 m and offshore distances ranging from 288 to 356 km from the Australian coastline. Microplastic counts ranged from 0 to 13.6 fragments g-1 dry sediment (mean of 1.26 ± 0.68; n = 51). We found higher microplastic counts than recorded in other microplastic analyses of deep-sea sediments. Sample fragments were identified as polyisoprene, polyurethane, polyester, and polypropylene. A statistical analysis detected a relationship between sediment microplastic counts and the amount of plastic floating on the ocean surface above, as well as with the angle of the seafloor slope. The number of microplastic fragments in the sediment increased as surface plastic counts increased, and as the seafloor slope angle increased. Overall, however, the microplastic counts were highly variable, with variation between sediment cores at the same location being greater than the variation across the sampling sites. Our findings of microplastics in deep-sea sediment from the Great Australian Bight contributes to understanding where some of the ‘hidden’ oceanic plastic pollution is distributed.

@article{doi103389fmars2020576170,
    author = "Barrett, Justine and Chase, Zanna and Zhang, Jing and Holl, Mark M. Banaszak and Willis, Kathryn and Williams, A. and Hardesty, Britta Denise and Wilcox, Chris",
    title = "Microplastic Pollution in Deep-Sea Sediments From the Great Australian Bight",
    year = "2020",
    journal = "Frontiers in Marine Science",
    abstract = "Interest in understanding the extent of plastic and specifically microplastic pollution has increased on a global scale. Still one large piece of the overall puzzle currently lacks: how much plastic pollution has found its way into the deeper areas of the world’s oceans? The extent of microplastic pollution in deep-sea sediments remains poorly quantified, but this knowledge is imperative for predicting the distribution and potential impacts of global plastic pollution. We quantified microplastics in deep-sea sediments from the Great Australian Bight using an adapted density separation and dye fluorescence technique. We analyzed sediment cores from six locations ranging in ocean depths from 1,655 to 3,062 m and offshore distances ranging from 288 to 356 km from the Australian coastline. Microplastic counts ranged from 0 to 13.6 fragments g-1 dry sediment (mean of 1.26 ± 0.68; n = 51). We found higher microplastic counts than recorded in other microplastic analyses of deep-sea sediments. Sample fragments were identified as polyisoprene, polyurethane, polyester, and polypropylene. A statistical analysis detected a relationship between sediment microplastic counts and the amount of plastic floating on the ocean surface above, as well as with the angle of the seafloor slope. The number of microplastic fragments in the sediment increased as surface plastic counts increased, and as the seafloor slope angle increased. Overall, however, the microplastic counts were highly variable, with variation between sediment cores at the same location being greater than the variation across the sampling sites. Our findings of microplastics in deep-sea sediment from the Great Australian Bight contributes to understanding where some of the ‘hidden’ oceanic plastic pollution is distributed.",
    url = "https://doi.org/10.3389/fmars.2020.576170",
    doi = "10.3389/fmars.2020.576170",
    openalex = "W3091991593",
    references = "doi1011552014823296"
}

Since deep-sea gas hydrate-bearing sediments were drilled for the first time in the Blake Ridge in 1970, gas hydrates have been discovered at 53 drill sites in the continental margins of global oceans with international scientific ocean drilling (DSDP/ODP/IODP Programs). As a result, massive amounts of geophysical well-logging data have been accumulated, which provide critical information for understanding the in-situ properties of gas hydrates and their host sediments. Gas hydrates have such physical and chemical properties as non-conductivity, low density, high acoustic velocity, and high hydrogen content, which form the basis of identifying gas hydrate reservoirs and predicting their distribution by well-logging data. A series of well-logging evaluation methods have been proposed to estimate gas hydrate saturation of sediments, including Archie equation, combined methods of density and nuclear magnetic resonance well logging, various forms of three-phase acoustic wave equations, and elastic wave velocity simulations based on different rock physical models. The distribution of gas hydrates is highly heterogeneous, which is mainly manifested in the selectivity of hydrate occurrence to the lithology of host sediments and to the nucleation sites within a host sediment of the same lithology. The scientific-ocean-drilling well logging data have also been preliminarily used for evaluating the heterogeneity of gas hydrate distribution and inferring the growth habit of gas hydrates in host sediments. Nevertheless, there still exist some problems. The formation models used in logging evaluation are in general oversimplified, in which only two or three stratal components are involved. The application of high-resolution logging while-drilling (LWD) data remains limited. Log interpretation is not closely integrated with core geology. Therefore, joint inversion of lithologic components, porosity and gas hydrate saturation based on more complex formation models, together with the applications of high-resolution LWD logging data and core calibration, may represent an important direction in future well-logging evaluation of gas hydrate reservoirs.

@article{doi101016jngib202008001,
    author = "Zhong, Guangfa and Zhang, Di and Zhao, Luanxiao",
    title = "Current states of well-logging evaluation of deep-sea gas hydrate-bearing sediments by the international scientific ocean drilling (DSDP/ODP/IODP) programs",
    year = "2021",
    journal = "Natural Gas Industry B",
    abstract = "Since deep-sea gas hydrate-bearing sediments were drilled for the first time in the Blake Ridge in 1970, gas hydrates have been discovered at 53 drill sites in the continental margins of global oceans with international scientific ocean drilling (DSDP/ODP/IODP Programs). As a result, massive amounts of geophysical well-logging data have been accumulated, which provide critical information for understanding the in-situ properties of gas hydrates and their host sediments. Gas hydrates have such physical and chemical properties as non-conductivity, low density, high acoustic velocity, and high hydrogen content, which form the basis of identifying gas hydrate reservoirs and predicting their distribution by well-logging data. A series of well-logging evaluation methods have been proposed to estimate gas hydrate saturation of sediments, including Archie equation, combined methods of density and nuclear magnetic resonance well logging, various forms of three-phase acoustic wave equations, and elastic wave velocity simulations based on different rock physical models. The distribution of gas hydrates is highly heterogeneous, which is mainly manifested in the selectivity of hydrate occurrence to the lithology of host sediments and to the nucleation sites within a host sediment of the same lithology. The scientific-ocean-drilling well logging data have also been preliminarily used for evaluating the heterogeneity of gas hydrate distribution and inferring the growth habit of gas hydrates in host sediments. Nevertheless, there still exist some problems. The formation models used in logging evaluation are in general oversimplified, in which only two or three stratal components are involved. The application of high-resolution logging while-drilling (LWD) data remains limited. Log interpretation is not closely integrated with core geology. Therefore, joint inversion of lithologic components, porosity and gas hydrate saturation based on more complex formation models, together with the applications of high-resolution LWD logging data and core calibration, may represent an important direction in future well-logging evaluation of gas hydrate reservoirs.",
    url = "https://doi.org/10.1016/j.ngib.2020.08.001",
    doi = "10.1016/j.ngib.2020.08.001",
    openalex = "W3153514171",
    references = "doi1010160025322771900533, doi1010291999gl900421, doi1010291999jb900175, doi1010292008rg000279, doi10106311712886, doi10119011440450, doi10119011442062, doi10119011444059, doi102118942054g, openalexw2267844404"
}

Abstract. In this work, we provide an extensive inventory of Pb and Nd radiogenic isotopes in surface sediments from the Southwestern Atlantic margin, aiming to interpret the role played by ocean circulation in sediment distribution. There are latitudinal trends for Pb and Nd isotopes, reflecting the different current systems acting on the margin. The utilization of sediment fingerprinting allowed us to associate the isotopic signatures to the main oceanographic forcings in the area. We recognized differences between the Nd and Pb sources for the sediments to the Argentinean shelf, carried by the Subantarctic Shelf Water, and slope, transported by deeper flows. Sediments from Antarctica extend up to the Uruguayan margin, carried by the Upper- and Lower Circumpolar Deep Water. Our data confirm that, for shelf and intermediate (up to 1,200 m water depth) areas, the transfer of sediments from the Argentinean margin to the North of 35° S is limited by the Subtropical Shelf Front and the recirculated Antarctic Intermediate Water. On the southern Brazilian margin, it is possible to recognize the northward influence of the Río de la Plata sediments carried by the Plata Plume Water. This influence is limited by the southward flow of waters transported by the Brazil Current. Finally, we propose that the Subtropical Shelf Front and the Santos Bifurcation act as boundaries of geochemical provinces in the area. Finally, a qualitative model of sediment sources and transport is provided for the Southwestern Atlantic margin.

@misc{doi105194os202144,
    author = "de Mahiques, Michel Michaelovitch and Violante, Roberto A. and Franco-Fraguas, Paula and Burone, Letícia and Rocha, César B. and Ortega, Leonardo and dos Santos, Rosangela Felício and Kim, Bianca Sung Mi and Figueira, Rubens César Lopes and Bı́cego, Márcia Caruso",
    title = "New insights of the influence of ocean circulation on the sedimentary distribution in the Southwestern Atlantic margin (23° S to 55° S) based on Nd and Pb isotopic fingerprinting",
    year = "2021",
    abstract = "Abstract. In this work, we provide an extensive inventory of Pb and Nd radiogenic isotopes in surface sediments from the Southwestern Atlantic margin, aiming to interpret the role played by ocean circulation in sediment distribution. There are latitudinal trends for Pb and Nd isotopes, reflecting the different current systems acting on the margin. The utilization of sediment fingerprinting allowed us to associate the isotopic signatures to the main oceanographic forcings in the area. We recognized differences between the Nd and Pb sources for the sediments to the Argentinean shelf, carried by the Subantarctic Shelf Water, and slope, transported by deeper flows. Sediments from Antarctica extend up to the Uruguayan margin, carried by the Upper- and Lower Circumpolar Deep Water. Our data confirm that, for shelf and intermediate (up to 1,200 m water depth) areas, the transfer of sediments from the Argentinean margin to the North of 35° S is limited by the Subtropical Shelf Front and the recirculated Antarctic Intermediate Water. On the southern Brazilian margin, it is possible to recognize the northward influence of the Río de la Plata sediments carried by the Plata Plume Water. This influence is limited by the southward flow of waters transported by the Brazil Current. Finally, we propose that the Subtropical Shelf Front and the Santos Bifurcation act as boundaries of geochemical provinces in the area. Finally, a qualitative model of sediment sources and transport is provided for the Southwestern Atlantic margin.",
    url = "https://doi.org/10.5194/os-2021-44",
    doi = "10.5194/os-2021-44",
    openalex = "W4230581807",
    references = "doi101016jrsma201705012"
}

Securing energy means grasping the key link in the national development and security strategy. Under the goals of carbon peak and carbon neutrality, the overall tendency of energy development is to increase the proportion of natural gas while stabilizing oil consumption, and the global primary energy is entering the era of natural gas. Gas hydrate in deep seabed shallow strata and extremely cold permafrost regions has piqued the interest of researchers due to its abundant resources, widespread distribution, and high energy density. Although the drilling of hydrate wells is still fraught with unknowns and challenges due to the technological barriers between countries, complex on-site working conditions, and unique physical chemical properties, accumulation forms, and occurrence characteristics of gas hydrate, more than ten successful trial productions around the world have opened the door of hope for the development of this potentially new energy. The gas hydrate reservoir drilling technique is the frontier and hotspot of scientific and technological innovation and competitiveness around the globe today, reflecting the level of oil and gas technical advancement. At the national level, it possesses strategic and revolutionary features. Innovative drilling techniques, scientific well location layout, appropriate wellbore structure and well trajectory design, efficient drilling fluid, qualified drilling and completion equipment, and successful pressure-temperature preserved coring may all provide a strong guarantee for the successful completion of gas hydrate wells. This review comprehensively reviews the drilling techniques and engineering measures that can be used to develop gas hydrate. It focuses on the research advancement of important hydrate drilling technologies and the enlightening significance of these developments in the application of hydrate drilling. This work will deliver valuable experience as well as comprehensive scientific information for gas hydrate exploration and drilling.

@article{doi103389feart2022997337,
    author = "Wei, Na and Pei, Jun and Zhao, Jinzhou and Zhang, Liehui and Zhou, Shouwei and Luo, Pingya and Li, Haitao and Wu, Jiang",
    title = "A state-of-the-art review and prospect of gas hydrate reservoir drilling techniques",
    year = "2022",
    journal = "Frontiers in Earth Science",
    abstract = "Securing energy means grasping the key link in the national development and security strategy. Under the goals of carbon peak and carbon neutrality, the overall tendency of energy development is to increase the proportion of natural gas while stabilizing oil consumption, and the global primary energy is entering the era of natural gas. Gas hydrate in deep seabed shallow strata and extremely cold permafrost regions has piqued the interest of researchers due to its abundant resources, widespread distribution, and high energy density. Although the drilling of hydrate wells is still fraught with unknowns and challenges due to the technological barriers between countries, complex on-site working conditions, and unique physical chemical properties, accumulation forms, and occurrence characteristics of gas hydrate, more than ten successful trial productions around the world have opened the door of hope for the development of this potentially new energy. The gas hydrate reservoir drilling technique is the frontier and hotspot of scientific and technological innovation and competitiveness around the globe today, reflecting the level of oil and gas technical advancement. At the national level, it possesses strategic and revolutionary features. Innovative drilling techniques, scientific well location layout, appropriate wellbore structure and well trajectory design, efficient drilling fluid, qualified drilling and completion equipment, and successful pressure-temperature preserved coring may all provide a strong guarantee for the successful completion of gas hydrate wells. This review comprehensively reviews the drilling techniques and engineering measures that can be used to develop gas hydrate. It focuses on the research advancement of important hydrate drilling technologies and the enlightening significance of these developments in the application of hydrate drilling. This work will deliver valuable experience as well as comprehensive scientific information for gas hydrate exploration and drilling.",
    url = "https://doi.org/10.3389/feart.2022.997337",
    doi = "10.3389/feart.2022.997337",
    openalex = "W4297312430",
    references = "doi101016japenergy201412061, doi101016japenergy201603101, doi101016jjngse200912004, doi101016jngib202008001, doi101016jrser201312025, doi101021acsenergyfuels6b01909, doi101021ef050427x, doi101039c9ra00755e, doi1031035cg2018003, doi1031035cg2020043, doi10404325243ms"
}

@article{doi101016jjsv2023118165,
    author = "Deng, Pengfei and Tan, Xing and Bai and Li, He",
    title = "Influence of blades’ shape and cutters’ arrangement of PDC drill bit on nonlinear vibration of deep drilling system",
    year = "2023",
    journal = "Journal of Sound and Vibration",
    url = "https://doi.org/10.1016/j.jsv.2023.118165",
    doi = "10.1016/j.jsv.2023.118165",
    openalex = "W4388687798",
    references = "doi103389feart2022997337"
}

Logging-while-drilling (LWD) sonic data is critical for marine gas hydrate reservoir evaluation and production prediction. However, acquiring complete acoustic logs, particularly shear-wave, poses significant challenges and incurs high costs. To tackle this issue, we develop a two-branch hybrid framework for predicting LWD sonic logs of hydrate-bearing sediments from existing logging data. One branch based on a rock physics model is utilized to generate background (no-hydrate/no-gas) elastic wave velocity profiles, while the other deep learning branch (DLB) compensates for the residuals between actual observations and the outputs of the first branch. The state-of-the-art Transformer encoder block is employed in the DLB to extract potentially intricate patterns within logging sequences. Such a scientific knowledge-guided network architecture with additional physics-based feature construction provides an explainable process that improves the physical consistency of predictions. Our method is tested with two publicly available datasets from the Cascadia continental margin. The hybrid model greatly enhances the predictive accuracy of the physical process model (with a minimum mean absolute percentage error of 0.73% and 4.33% for P- and S-wave velocities, respectively) and demonstrates outstanding generalization performance compared to pure data-driven approaches. The well-trained model offers impressive extrapolation beyond observed conditions for unmeasured high hydrate saturation (>40%) intervals in the region.

@article{doi101109tgrs20233330869,
    author = "Li, Zikun and Xia, Jialong and Liu, Zhichao and Lei, Gang and Lee, Kyungbook and Ning, Fulong",
    title = "Missing Sonic Logs Generation for Gas Hydrate-Bearing Sediments via Hybrid Networks Combining Deep Learning With Rock Physics Modeling",
    year = "2023",
    journal = "IEEE Transactions on Geoscience and Remote Sensing",
    abstract = "Logging-while-drilling (LWD) sonic data is critical for marine gas hydrate reservoir evaluation and production prediction. However, acquiring complete acoustic logs, particularly shear-wave, poses significant challenges and incurs high costs. To tackle this issue, we develop a two-branch hybrid framework for predicting LWD sonic logs of hydrate-bearing sediments from existing logging data. One branch based on a rock physics model is utilized to generate background (no-hydrate/no-gas) elastic wave velocity profiles, while the other deep learning branch (DLB) compensates for the residuals between actual observations and the outputs of the first branch. The state-of-the-art Transformer encoder block is employed in the DLB to extract potentially intricate patterns within logging sequences. Such a scientific knowledge-guided network architecture with additional physics-based feature construction provides an explainable process that improves the physical consistency of predictions. Our method is tested with two publicly available datasets from the Cascadia continental margin. The hybrid model greatly enhances the predictive accuracy of the physical process model (with a minimum mean absolute percentage error of 0.73\% and 4.33\% for P- and S-wave velocities, respectively) and demonstrates outstanding generalization performance compared to pure data-driven approaches. The well-trained model offers impressive extrapolation beyond observed conditions for unmeasured high hydrate saturation (>40\%) intervals in the region.",
    url = "https://doi.org/10.1109/tgrs.2023.3330869",
    doi = "10.1109/tgrs.2023.3330869",
    openalex = "W4388469778",
    references = "doi101007978331946493038, doi101016jjcp201810045, doi101016jngib202008001, doi101037h0042519, doi101038323533a0, doi101038s4158601909121, doi10110978650093, doi101162neco1997981735, doi102118942054g, doi104230lipicsitp202319"
}

The occurrence of deep-sea geohazards is accompanied by dynamic changes in the physical properties of seafloor sediments. Therefore, studying the physical properties is helpful for monitoring and early warnings of deep-sea geohazards. Existing physical property inversion methods have problems regarding the poor inversion accuracy and limited application scope. To address these issues, we establish a deep learning model between the resistivity of seafloor sediment and its density, water content, and porosity. Compared with empirical formulas, the deep learning model has the advantages of a more concentrated prediction range and a higher prediction accuracy. This algorithm was applied to invert the spatial distribution characteristics and temporal variation of the seafloor sediment density, water content, and porosity in the South China Sea hydrate test area for 12 days. The study reveals that the dynamic changes in the physical properties of seafloor sediments in the South China Sea hydrate zone exhibit obvious stratification characteristics. The dynamic changes in the physical properties of seafloor sediments are mainly observed at depths of 0–0.9 m below the seafloor, and the sediment properties remain stable at depths of 0.9–1.8 m below the seafloor. This study achieves the monitoring and early warning of dynamic changes in the physical properties of seafloor sediments and provides a guarantee for the safe construction of marine engineering.

@article{doi103390jmse11050937,
    author = "Sun, Zhiwen and Fan, Zhihan and Zhu, Chaoqi and Li, Kai and Sun, Zhongqiang and Song, Xiaoshuai and Xue, Liang and Liu, Hanlu and Jia, Yonggang",
    title = "Study on the Relationship between Resistivity and the Physical Properties of Seafloor Sediments Based on the Deep Neural Learning Algorithm",
    year = "2023",
    journal = "Journal of Marine Science and Engineering",
    abstract = "The occurrence of deep-sea geohazards is accompanied by dynamic changes in the physical properties of seafloor sediments. Therefore, studying the physical properties is helpful for monitoring and early warnings of deep-sea geohazards. Existing physical property inversion methods have problems regarding the poor inversion accuracy and limited application scope. To address these issues, we establish a deep learning model between the resistivity of seafloor sediment and its density, water content, and porosity. Compared with empirical formulas, the deep learning model has the advantages of a more concentrated prediction range and a higher prediction accuracy. This algorithm was applied to invert the spatial distribution characteristics and temporal variation of the seafloor sediment density, water content, and porosity in the South China Sea hydrate test area for 12 days. The study reveals that the dynamic changes in the physical properties of seafloor sediments in the South China Sea hydrate zone exhibit obvious stratification characteristics. The dynamic changes in the physical properties of seafloor sediments are mainly observed at depths of 0–0.9 m below the seafloor, and the sediment properties remain stable at depths of 0.9–1.8 m below the seafloor. This study achieves the monitoring and early warning of dynamic changes in the physical properties of seafloor sediments and provides a guarantee for the safe construction of marine engineering.",
    url = "https://doi.org/10.3390/jmse11050937",
    doi = "10.3390/jmse11050937",
    openalex = "W4367298297",
    references = "doi101016jegyr202201097"
}

This research explores the geomechanical challenges associated with gas hydrate extraction in submarine slope zones, a setting posing a high risk of significant geological calamities. We investigate slope and wellbore deformations driven by hydrate decomposition within a subsea environment. Utilizing Abaqus, a fluid-solid-thermal multi-field coupling model for gas hydrate reservoirs was created. Hydrate decomposition during drilling is minimal, resulting in minor formation deformation near the wellbore. However, a year of hydrate production caused a maximum displacement of up to 7 m in the wellbore and formation, highlighting the risk of submarine landslides. This indicates the need for meticulous surveillance of formation subsidence and wellhead equipment displacement. In the aftermath of a hydrate-induced submarine landslide, both the hydrate layer and the overlying strata descend together, inflicting considerable damage on the formation and wellbore. Our study presents a holistic examination of the interplay between environmental geomechanics risks and engineering structure risks for submarine slope instability and wellbore stability during hydrate development, providing crucial insights for enhancing safety measures in hydrate drilling and production, and ensuring wellbore stability.

@article{doi103390jmse11112069,
    author = "He, Yufa and Song, Benjian and Li, Qingping",
    title = "Coupling Submarine Slope Stability and Wellbore Stability Analysis with Natural Gas Hydrate Drilling and Production in Submarine Slope Strata in the South China Sea",
    year = "2023",
    journal = "Journal of Marine Science and Engineering",
    abstract = "This research explores the geomechanical challenges associated with gas hydrate extraction in submarine slope zones, a setting posing a high risk of significant geological calamities. We investigate slope and wellbore deformations driven by hydrate decomposition within a subsea environment. Utilizing Abaqus, a fluid-solid-thermal multi-field coupling model for gas hydrate reservoirs was created. Hydrate decomposition during drilling is minimal, resulting in minor formation deformation near the wellbore. However, a year of hydrate production caused a maximum displacement of up to 7 m in the wellbore and formation, highlighting the risk of submarine landslides. This indicates the need for meticulous surveillance of formation subsidence and wellhead equipment displacement. In the aftermath of a hydrate-induced submarine landslide, both the hydrate layer and the overlying strata descend together, inflicting considerable damage on the formation and wellbore. Our study presents a holistic examination of the interplay between environmental geomechanics risks and engineering structure risks for submarine slope instability and wellbore stability during hydrate development, providing crucial insights for enhancing safety measures in hydrate drilling and production, and ensuring wellbore stability.",
    url = "https://doi.org/10.3390/jmse11112069",
    doi = "10.3390/jmse11112069",
    openalex = "W4388017649",
    references = "doi103389feart2022997337"
}

The data of azimuthal electromagnetic (EM) Logging-While-Drilling (LWD) tool is crucial for controlling and optimizing the trajectory of the wellbore, making it a key technology in geosteering. However, the measurement of the tool involves multiple frequencies, spaces, and sectors, leading to a significant volume of measured data that can’t be uploaded in real-time. Attempting to invert formation resistivity and boundaries based solely on the limited data that transmitted to the surface may not accurately reflect the true formation model. Therefore, this paper proposes a method for supplementing the measurement curves of the tool based on deep learning. The intelligent method can predict the missing logging information according to limited data and improve the utilization efficiency of logging data. Firstly, the database of azimuthal EM LWD is generated using various synthetic formation models and numerical forward modeling techniques, and the complete logging data is artificially separated into known logging data and missing logging data. Then, three deep learning models are established based on LSTM, GRU, and UNET networks respectively, and use the above sample database for training and testing them. The results demonstrate that missing curves of the tool’s measurement can be accurately and efficiently predicted using deep learning techniques. Finally, the original logging data and the complete logging data after supplementing are used for inverting the formation information. The result shows that the latter yields higher inversion accuracy. Moreover, the difference in inversion accuracy will grow as the complexity of the formation model increases after data supplementing. Therefore, the data supplement of azimuthal EM LWD by deep learning is very important for the accurate inversion of complex formation models.

@article{doi101109access20243406755,
    author = "Zhang, Liangchen and Qin, Haojie and Yang, Xiangyu and Yanbo, Zong",
    title = "The Data Supplement Method of Azimuthal EM LWD Based on Deep Learning",
    year = "2024",
    journal = "IEEE Access",
    abstract = "The data of azimuthal electromagnetic (EM) Logging-While-Drilling (LWD) tool is crucial for controlling and optimizing the trajectory of the wellbore, making it a key technology in geosteering. However, the measurement of the tool involves multiple frequencies, spaces, and sectors, leading to a significant volume of measured data that can’t be uploaded in real-time. Attempting to invert formation resistivity and boundaries based solely on the limited data that transmitted to the surface may not accurately reflect the true formation model. Therefore, this paper proposes a method for supplementing the measurement curves of the tool based on deep learning. The intelligent method can predict the missing logging information according to limited data and improve the utilization efficiency of logging data. Firstly, the database of azimuthal EM LWD is generated using various synthetic formation models and numerical forward modeling techniques, and the complete logging data is artificially separated into known logging data and missing logging data. Then, three deep learning models are established based on LSTM, GRU, and UNET networks respectively, and use the above sample database for training and testing them. The results demonstrate that missing curves of the tool’s measurement can be accurately and efficiently predicted using deep learning techniques. Finally, the original logging data and the complete logging data after supplementing are used for inverting the formation information. The result shows that the latter yields higher inversion accuracy. Moreover, the difference in inversion accuracy will grow as the complexity of the formation model increases after data supplementing. Therefore, the data supplement of azimuthal EM LWD by deep learning is very important for the accurate inversion of complex formation models.",
    url = "https://doi.org/10.1109/access.2024.3406755",
    doi = "10.1109/access.2024.3406755",
    openalex = "W4399110635",
    references = "doi101109tgrs20233330869"
}

Climate change has become one of the most pressing global challenges, with greenhouse gas emissions, particularly carbon dioxide (CO2), being the primary drivers of global warming. To effectively address climate change, reducing carbon emissions has become an urgent task for countries worldwide. Carbon capture, utilization, and storage (CCUS) technologies are regarded as crucial measures to combat climate change, among which ocean CO2 sequestration has emerged as a promising approach. Recent reports from the International Energy Agency (IEA) indicate that by 2060, CCUS technologies could contribute up to 14% of global cumulative carbon reductions, highlighting their significant potential in mitigating climate change. This review discusses the main technological pathways for ocean CO2 sequestration, including oceanic water column sequestration, CO2 oil and gas/coal seam geological sequestration, saline aquifer sequestration, and seabed methane hydrate sequestration. The current research status and challenges of these technologies are reviewed, with a particular focus on the potential of seabed methane hydrate sequestration, which offers a storage density of approximately 0.5 to 1.0 Gt per cubic kilometer of hydrate. This article delves into the formation mechanisms, stability conditions, and storage advantages of CO2 hydrates. CO2 sequestration via hydrates not only offers high storage density but also ensures long-term stability in the low-temperature, high-pressure conditions of the seabed, minimizing leakage risks. This makes it one of the most promising ocean CO2 sequestration technologies. This paper also analyzes the difficulties faced by ocean CO2 sequestration technologies, such as the kinetic limitations of hydrate formation and leakage monitoring during the sequestration process. Finally, this paper looks ahead to the future development of ocean CO2 sequestration technologies, providing theoretical support and practical guidance for optimizing their application and promoting a low-carbon economy.

@article{doi103390en18040942,
    author = "Zhang, Shanling and Jiang, Sheng and Li, Hongda and Li, Peiran and Zhong, Xiuping and Chen, Chen and Tu, Guigang and Liu, Xiang and Xu, Zhenhua",
    title = "Current Status and Reflections on Ocean CO2 Sequestration: A Review",
    year = "2025",
    journal = "Energies",
    abstract = "Climate change has become one of the most pressing global challenges, with greenhouse gas emissions, particularly carbon dioxide (CO2), being the primary drivers of global warming. To effectively address climate change, reducing carbon emissions has become an urgent task for countries worldwide. Carbon capture, utilization, and storage (CCUS) technologies are regarded as crucial measures to combat climate change, among which ocean CO2 sequestration has emerged as a promising approach. Recent reports from the International Energy Agency (IEA) indicate that by 2060, CCUS technologies could contribute up to 14\% of global cumulative carbon reductions, highlighting their significant potential in mitigating climate change. This review discusses the main technological pathways for ocean CO2 sequestration, including oceanic water column sequestration, CO2 oil and gas/coal seam geological sequestration, saline aquifer sequestration, and seabed methane hydrate sequestration. The current research status and challenges of these technologies are reviewed, with a particular focus on the potential of seabed methane hydrate sequestration, which offers a storage density of approximately 0.5 to 1.0 Gt per cubic kilometer of hydrate. This article delves into the formation mechanisms, stability conditions, and storage advantages of CO2 hydrates. CO2 sequestration via hydrates not only offers high storage density but also ensures long-term stability in the low-temperature, high-pressure conditions of the seabed, minimizing leakage risks. This makes it one of the most promising ocean CO2 sequestration technologies. This paper also analyzes the difficulties faced by ocean CO2 sequestration technologies, such as the kinetic limitations of hydrate formation and leakage monitoring during the sequestration process. Finally, this paper looks ahead to the future development of ocean CO2 sequestration technologies, providing theoretical support and practical guidance for optimizing their application and promoting a low-carbon economy.",
    url = "https://doi.org/10.3390/en18040942",
    doi = "10.3390/en18040942",
    openalex = "W4407670330",
    references = "doi101016jjgsce2024205269"
}