Abstract Major climate transitions and perturbations in global carbon cycle are known to have occurred during the Eocene, between 56 and 34 million years ago (Ma). A series of carbon isotope excursions (CIEs) mark variations in the global carbon cycle and changes in climate through early Eocene. Paleocene-Eocene Thermal Maximum (PETM) ca. 56 Ma is the most pronounced and well documented of these events expressed as a clay rich layer in many deep-sea sections, resulting from widespread carbonate dissolution on the seafloor, which is in turn related to shoaling of the carbonate compensation depth (CCD) and lysocline. Other CIEs of early Eocene had similar response. However, response of these geologically ‘instantaneous’ hyperthermals differ from long-term warmth (multi-million-year time scale) of the Early Eocene Climate Optimum (EECO) in terms of sea-floor carbonate accumulation. Following the termination of EECO, earth's climate transitioned into long-term cooling. Pronounced fluctuations in CCD of equatorial Pacific are known to have occurred during middle-late Eocene as well, whose global extent and origin are still unresolved. Most proxy records either span the interval of early Eocene or document particular climatic events in Eocene, which significantly limits visualizing the long-term Eocene climate change and response of open marine carbonate preservation. The present study documents change in carbonate dissolution and carbonate mass accumulation rate through the entire Eocene (56–34 Ma) at ODP Site 1209 on Shatsky Rise, north-central Pacific and ties it to a stable carbon and oxygen isotope record. Our study determines the correlation between deep-sea carbonate dissolution and carbon cycling process during the dynamic climate regime of Eocene. A strong correlation between magnitude of CIEs and intensity of dissolution for early Eocene hyperthermal events appears to significantly weaken for multiple dissolution events in middle-late Eocene, thereby indicating fundamental difference in their causal mechanism.

中文翻译：

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太平洋中北部始新世碳酸盐沉积：来自 Shatsky Rise 1209 号海洋钻探计划站点的新见解

摘要 已知全球碳循环中的主要气候转变和扰动发生在始新世期间，即 56 至 3400 万年前（Ma）。一系列碳同位素漂移 (CIE) 标志着全球碳循环的变化和始新世早期气候的变化。古新世-始新世热最大值 (PETM) 约。56 Ma 是这些事件中最明显和有据可查的，在许多深海剖面中表现为富含粘土的层，这是由于海底广泛的碳酸盐溶解引起的，而这又与碳酸盐补偿深度 (CCD) 和浅滩形成有关。溶血素。始新世早期的其他 CIE 也有类似的反应。然而，就海底碳酸盐堆积而言，这些地质“瞬时”高温的响应不同于早始新世气候最优（EECO）的长期温暖（数百万年时间尺度）。EECO 终止后，地球气候转变为长期降温。赤道太平洋CCD的显着波动也发生在始新世中晚期，其全球范围和起源仍未得到解决。大多数代理记录要么跨越早始新世，要么记录始新世的特定气候事件，这极大地限制了始新世长期气候变化和开放海洋碳酸盐保存响应的可视化。本研究记录了太平洋中北部沙茨基隆起 ODP 站点 1209 整个始新世（56-34 Ma）的碳酸盐溶解和碳酸盐质量积累速率的变化，并将其与稳定的碳和氧同位素记录联系起来。我们的研究确定了始新世动态气候制度下深海碳酸盐溶解与碳循环过程之间的相关性。始新世早期高温事件的 CIE 量级与溶蚀强度之间的强相关性似乎在始新世中晚期的多次溶蚀事件中显着减弱，从而表明它们的因果机制存在根本差异。我们的研究确定了始新世动态气候制度下深海碳酸盐溶解与碳循环过程之间的相关性。始新世早期高温事件的 CIE 量级与溶蚀强度之间的强相关性似乎在始新世中晚期的多次溶蚀事件中显着减弱，从而表明它们的因果机制存在根本差异。我们的研究确定了始新世动态气候制度下深海碳酸盐溶解与碳循环过程之间的相关性。始新世早期高温事件的 CIE 量级与溶蚀强度之间的强相关性似乎在始新世中晚期的多次溶蚀事件中显着减弱，从而表明它们的因果机制存在根本差异。