TY - JOUR
T1 - Conodont calcium isotopic evidence for multiple shelf acidification events during the Early Triassic
AU - Song, Haijun
AU - Song, Huyue
AU - Tong, Jinnan
AU - Gordon, Gwyneth W.
AU - Wignall, Paul B.
AU - Tian, Li
AU - Zheng, Wang
AU - Algeo, Thomas J.
AU - Liang, Lei
AU - Bai, Ruoyu
AU - Wu, Kui
AU - Anbar, Ariel D.
N1 - Funding Information:
We thank Jiuyuan Wang and Matt Fantle for constructive reviews of this study, and Dhilip Kumar and Donald Porcelli for editorial handling of the manuscript. This study was supported by the National Natural Science Foundation of China ( 41821001 , 41622207 , 41530104 , 41602024 , 41661134047 ), the Strategic Priority Research Program of Chinese Academy of Sciences ( XDB26000000 ), the State Key R&D project of China ( 2016YFA0601100 ), the Natural Science Foundation of Hubei ( 2017CFB610 ), the 111 Project ( B08030 ), and by grants to A.D.A. and T.J.A. from the U.S. National Science Foundation and NASA Exobiology program , and to P.B.W. from the Natural Research Council Grant NE/P0137224/1 . This study is a contribution to the international IMBER project and IGCP 630.
Publisher Copyright:
© 2020 Elsevier B.V.
PY - 2021/2/20
Y1 - 2021/2/20
N2 - The marine calcium (Ca) cycle is controlled by rates of continental weathering, seawater pH, and carbonate deposition on the seafloor and is linked to atmospheric CO2, climate change, and marine biotic evolution. Here, we provide the first continuous seawater Ca isotope profile from conodont apatite in South China for the latest Permian to early Middle Triassic, revealing major fluctuations in the Early Triassic calcium cycle. Three episodes of decreasing conodont δ44/40Ca (by 0.16–0.23‰) occurred around the Permian-Triassic, Smithian-Spathian, and Olenekian-Anisian boundaries. The first episode, coincident with a negative excursion of carbonate carbon isotopes, global warming, oceanic anoxia, enhanced weathering, and sea-level fall, was likely caused by a combination of volcanic CO2 release, ocean acidification, a reduced skeletal carbonate sink, and enhanced weathering of shelf carbonates. The latter two episodes, coincident with positive excursions of carbon isotopes, global cooling, and oceanic anoxia, possibly resulted from upwelling-driven shelf acidification and reduced skeletal carbonate burial. All three events were associated with marine biotic diversity losses, demonstrating a link between the calcium cycle and mass extinctions.
AB - The marine calcium (Ca) cycle is controlled by rates of continental weathering, seawater pH, and carbonate deposition on the seafloor and is linked to atmospheric CO2, climate change, and marine biotic evolution. Here, we provide the first continuous seawater Ca isotope profile from conodont apatite in South China for the latest Permian to early Middle Triassic, revealing major fluctuations in the Early Triassic calcium cycle. Three episodes of decreasing conodont δ44/40Ca (by 0.16–0.23‰) occurred around the Permian-Triassic, Smithian-Spathian, and Olenekian-Anisian boundaries. The first episode, coincident with a negative excursion of carbonate carbon isotopes, global warming, oceanic anoxia, enhanced weathering, and sea-level fall, was likely caused by a combination of volcanic CO2 release, ocean acidification, a reduced skeletal carbonate sink, and enhanced weathering of shelf carbonates. The latter two episodes, coincident with positive excursions of carbon isotopes, global cooling, and oceanic anoxia, possibly resulted from upwelling-driven shelf acidification and reduced skeletal carbonate burial. All three events were associated with marine biotic diversity losses, demonstrating a link between the calcium cycle and mass extinctions.
KW - Ca isotope
KW - Mass extinction
KW - Permian-Triassic
KW - Seawater chemistry
KW - Smithian-Spathian
KW - Upwelling
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U2 - 10.1016/j.chemgeo.2020.120038
DO - 10.1016/j.chemgeo.2020.120038
M3 - Article
AN - SCOPUS:85099363051
SN - 0009-2541
VL - 562
JO - Chemical Geology
JF - Chemical Geology
M1 - 120038
ER -