A Cenozoic record of the equatorial Pacific carbonate compensation depth
A Cenozoic record of the equatorial Pacific carbonate compensation depth
复制标题
赤道太平洋碳酸盐补偿深度的新生代记录
DOI：
10.1038/nature11360
复制
发表时间：
2012-08-30
期刊：
影响因子：
64.8
通讯作者：
Zeebe, Richard E.
中科院分区：
文献类型：
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作者：
Paelike, Heiko;Lyle, Mitchell W.;Zeebe, Richard E.
大气二氧化碳浓度和气候在地质时间尺度上受到火山和变质释气的碳输入与风化反馈的去除之间的平衡的调节;这些反馈涉及硅酸盐岩石和含有机碳岩石的侵蚀。这些过程的综合效应反映在碳酸钙补偿深度上，这是碳酸钙溶解的海洋深度。在这里，我们提出了一个碳酸盐积累记录，涵盖了过去5300万年的深度断面在赤道太平洋。碳酸盐补偿深度跟踪长期海洋冷却，从新生代早期（约5 500万年前）的3.0-3.5公里加深到目前的4.6公里，与新生代风化的总体增加一致。我们发现在中晚始新世碳酸盐补偿深度的大叠加波动。使用地球系统模型，我们确定风化的变化和模式的有机碳输送作为两个关键过程来解释这些大规模的始新世碳酸盐补偿深度的波动。
Atmospheric carbon dioxide concentrations and climate are regulated on geological timescales by the balance between carbon input from volcanic and metamorphic outgassing and its removal by weathering feedbacks; these feedbacks involve the erosion of silicate rocks and organic-carbon-bearing rocks. The integrated effect of these processes is reflected in the calcium carbonate compensation depth, which is the oceanic depth at which calcium carbonate is dissolved. Here we present a carbonate accumulation record that covers the past 53 million years from a depth transect in the equatorial Pacific Ocean. The carbonate compensation depth tracks long-term ocean cooling, deepening from 3.0–3.5 kilometres during the early Cenozoic (approximately 55 million years ago) to 4.6 kilometres at present, consistent with an overall Cenozoic increase in weathering. We find large superimposed fluctuations in carbonate compensation depth during the middle and late Eocene. Using Earth system models, we identify changes in weathering and the mode of organic-carbon delivery as two key processes to explain these large-scale Eocene fluctuations of the carbonate compensation depth.