Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans
Abstract During the Late Cretaceous, Earth's climate oscillated between warm and cool states, and global oceans changed between anoxic and oxic conditions, resulting in black/gray shales and oceanic red beds (ORBs) deposition, respectively. To understand such climate/ocean dynamics, this study...
| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
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Wiley
2022-04-01
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| Series: | Geochemistry, Geophysics, Geosystems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2021GC010292 |
| _version_ | 1797638022182731776 |
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| author | Ruiyang Sun Hanwei Yao Changzhou Deng Stephen E. Grasby Chengshan Wang Xi Chen Runsheng Yin |
| author_facet | Ruiyang Sun Hanwei Yao Changzhou Deng Stephen E. Grasby Chengshan Wang Xi Chen Runsheng Yin |
| author_sort | Ruiyang Sun |
| collection | DOAJ |
| description | Abstract During the Late Cretaceous, Earth's climate oscillated between warm and cool states, and global oceans changed between anoxic and oxic conditions, resulting in black/gray shales and oceanic red beds (ORBs) deposition, respectively. To understand such climate/ocean dynamics, this study investigated bulk Hg and Hg isotopes, as well as Fe3+/Fe2+ in Upper Cretaceous sediments deposited in southern Tibet and the North Atlantic. In both areas, black/gray shales show much higher Hg concentrations than ORBs, indicating enhanced Hg flux to global oceans during time of black/gray shale deposition. Black/gray shales show lower Fe3+/Fe2+ and positive Δ199Hg, suggesting a significant input of Hg into the anoxic/dysoxic ocean via atmospheric deposition. The isotope values are consistent with a volcanic source for this excess Hg. ORBs show high Fe3+/Fe2+ and negative shifts of Δ199Hg, suggesting that the dominant source of Hg into the oxic oceans was via terrestrial runoff. This study suggests that volcanism was an important driver of the climate/ocean dynamics during the Late Cretaceous. |
| first_indexed | 2024-03-11T12:57:42Z |
| format | Article |
| id | doaj.art-96a4c39b59f04809999e58fc37ff9dea |
| institution | Directory Open Access Journal |
| issn | 1525-2027 |
| language | English |
| last_indexed | 2024-03-11T12:57:42Z |
| publishDate | 2022-04-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj.art-96a4c39b59f04809999e58fc37ff9dea2023-11-03T16:56:16ZengWileyGeochemistry, Geophysics, Geosystems1525-20272022-04-01234n/an/a10.1029/2021GC010292Volcanism‐Triggered Climatic Control on Late Cretaceous OceansRuiyang Sun0Hanwei Yao1Changzhou Deng2Stephen E. Grasby3Chengshan Wang4Xi Chen5Runsheng Yin6State Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang ChinaState Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Beijing ChinaState Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang ChinaGeological Survey of Canada, Calgary Natural Resources Canada Calgary AB CanadaState Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Beijing ChinaState Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Beijing ChinaState Key Laboratory of Ore Deposit Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang ChinaAbstract During the Late Cretaceous, Earth's climate oscillated between warm and cool states, and global oceans changed between anoxic and oxic conditions, resulting in black/gray shales and oceanic red beds (ORBs) deposition, respectively. To understand such climate/ocean dynamics, this study investigated bulk Hg and Hg isotopes, as well as Fe3+/Fe2+ in Upper Cretaceous sediments deposited in southern Tibet and the North Atlantic. In both areas, black/gray shales show much higher Hg concentrations than ORBs, indicating enhanced Hg flux to global oceans during time of black/gray shale deposition. Black/gray shales show lower Fe3+/Fe2+ and positive Δ199Hg, suggesting a significant input of Hg into the anoxic/dysoxic ocean via atmospheric deposition. The isotope values are consistent with a volcanic source for this excess Hg. ORBs show high Fe3+/Fe2+ and negative shifts of Δ199Hg, suggesting that the dominant source of Hg into the oxic oceans was via terrestrial runoff. This study suggests that volcanism was an important driver of the climate/ocean dynamics during the Late Cretaceous.https://doi.org/10.1029/2021GC010292mercuryLate Cretaceousvolcanismclimate/ocean dynamicsblack shaleoceanic red beds |
| spellingShingle | Ruiyang Sun Hanwei Yao Changzhou Deng Stephen E. Grasby Chengshan Wang Xi Chen Runsheng Yin Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans Geochemistry, Geophysics, Geosystems mercury Late Cretaceous volcanism climate/ocean dynamics black shale oceanic red beds |
| title | Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans |
| title_full | Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans |
| title_fullStr | Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans |
| title_full_unstemmed | Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans |
| title_short | Volcanism‐Triggered Climatic Control on Late Cretaceous Oceans |
| title_sort | volcanism triggered climatic control on late cretaceous oceans |
| topic | mercury Late Cretaceous volcanism climate/ocean dynamics black shale oceanic red beds |
| url | https://doi.org/10.1029/2021GC010292 |
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