| DOI: | 10.1038/ngeo1707
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| 论文题名: | Antarctic weathering and carbonate compensation at the Eocene-Oligocene transition |
| 作者: | Basak C.; Martin E.E.
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| 刊名: | Nature Geoscience
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| ISSN: | 17520894
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| 出版年: | 2013
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| 卷: | 6, 期:2 | | 起始页码: | 121
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| 结束页码: | 124
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| 语种: | 英语
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| Scopus关键词: | alkalinity
; atmospheric chemistry
; basement rock
; carbon dioxide
; carbonate
; chemical weathering
; deep-sea sediment
; Eocene-Oligocene boundary
; ice cover
; ice sheet
; lead isotope
; paleogeography
; reconstruction
; seawater
; Antarctica
; Southern Ocean
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| 英文摘要: | During the Eocene-Oligocene transition about 34 million years ago, permanent ice cover developed on Antarctica. This pronounced climate transition was accompanied by the deepening of the carbonate compensation depth in the oceans and perturbations in atmospheric carbon dioxide concentrations. These changes may have been linked to continental weathering on Antarctica, but reconstructing which rock types were subject to weathering and the intensity of that weathering has proved challenging. Here we compare the lead (Pb) isotope values of seawater as recorded by extractions from decarbonated bulk sediments and those of silicate detrital fractions from deep-sea sediments from sites in the Southern Ocean that span the Eocene-Oligocene transition. These comparisons allowed us to assess local weathering inputs of Pb from Antarctica. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios suggest high rates of chemical weathering in the late Eocene, which would have helped draw down atmospheric CO2 to levels necessary for glacial initiation. Mechanical weathering and the introduction of newly exposed material was enhanced during the establishment of the Antarctic ice sheet. We also observe a divergence of seawater 206Pb/204Pb from detrital values during the Eocene-Oligocene transition, which implies an additional source of weathered material. We argue that the weathering of carbonate basement rock from Antarctica could explain the 206Pb/204Pb trend, and could have contributed to the observed deepening of the carbonate compensation depth through contributions to ocean alkalinity. © 2013 Macmillan Publishers Limited. All rights reserved. |
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| 资源类型: | 期刊论文
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| 标识符: | http://119.78.100.158/handle/2HF3EXSE/106869
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| Appears in Collections: | 气候减缓与适应
科学计划与规划
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作者单位: | Department of Geological Sciences, University of Florida, Gainesville, FL 32611, United States
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| Recommended Citation: | |
Basak C.,Martin E.E.. Antarctic weathering and carbonate compensation at the Eocene-Oligocene transition[J]. Nature Geoscience,2013-01-01,6(2)
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