Miocene restriction of the Pacific-North Atlantic throughflow strengthened Atlantic overturning circulation
Miocene restriction of the Pacific-North Atlantic throughflow strengthened Atlantic overturning circulation
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DOI：
10.1038/s41467-019-12034-7
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发表时间：
2019-09
影响因子：
16.6
通讯作者：
V. Kirillova;Anne H. Osborne;Tjördis Störling;M. Frank
中科院分区：
文献类型：
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作者：
V. Kirillova;Anne H. Osborne;Tjördis Störling;M. Frank
从加勒比海向北大西洋输出温暖和咸沃茨是大西洋经向翻转环流的一个重要组成部分。然而，在中新世期间也有活跃的AMOC，尽管有证据表明开放的中美洲航道（CAS）允许低盐度的太平洋沃茨进入加勒比海。为了解决这一明显的矛盾，并限制CAS关闭的时间，我们提出了第一个连续的Nd同位素记录的中间沃茨在佛罗里达海峡在过去的1250万年。我们的研究结果表明，有没有直接的中间水团出口从加勒比到佛罗里达海峡之间的11.5和9.5马，在同一时间作为一个加强AMOC。9 Ma后，由于CAS关闭的一个重大步骤以及随后停止低盐度太平洋沃茨进入加勒比海，维持了一个强AMOC。
Export of warm and salty waters from the Caribbean to the North Atlantic is an essential component of the Atlantic Meridional Overturning Circulation (AMOC). However, there was also an active AMOC during the Miocene, despite evidence for an open Central American Seaway (CAS) that would have allowed low-salinity Pacific waters to enter the Caribbean. To address this apparent contradiction and to constrain the timing of CAS closure we present the first continuous Nd isotope record of intermediate waters in the Florida Strait over the past 12.5 million years. Our results indicate that there was no direct intermediate water mass export from the Caribbean to the Florida Strait between 11.5 and 9.5 Ma, at the same time as a strengthened AMOC. After 9 Ma a strong AMOC was maintained due to a major step in CAS closure and the consequent cessation of low-salinity Pacific waters entering the Caribbean.