Active North Atlantic deepwater formation during Heinrich Stadial 1
Active North Atlantic deepwater formation during Heinrich Stadial 1
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DOI：
10.1016/j.quascirev.2021.107145
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发表时间：
2021-10
影响因子：
4
通讯作者：
J. Repschläger;N. Zhao;D. Rand;L. Lisiecki;J. Muglia;S. Mulitza;A. Schmittner;O. Cartapanis;H. Bauch;R. Schiebel;G. Haug
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作者：
J. Repschläger;N. Zhao;D. Rand;L. Lisiecki;J. Muglia;S. Mulitza;A. Schmittner;O. Cartapanis;H. Bauch;R. Schiebel;G. Haug
深水环流在最后一次冰川消退过程中发生了显着变化，从浅冰盖到深冰盖。这种变化伴随着同位素较轻的海水进入深渊，以及深海变暖，将深海分层从盐度控制模式改变为温度控制模式。然而，导致这些变化的确切机制仍不清楚。此外，在海因里希阶梯1(HS1)(17.5-14.6KYR BP)期间完全关闭北大西洋深水地层的长期观点仍然盛行。在这里，我们介绍了一种新的北大西洋海底δ13C和δ18O数据的汇编，该数据具有一致的时间分辨率和一致的年龄模型，作为国际PAGE工作组OC3的一部分，以研究北大西洋的深水特性。这项广泛的汇编包括105个沉积物岩芯，揭示了HS1期间不同的水团。冰岛盆地有大量的δ13C和δ18O标志的水团，而在20到50°N之间，18O耗尽的独特舌头，13C的富集水可以到达4000微米的水深。严重的δ13C信号表明，在HS1期间，北大西洋的深水形成活跃。其δ18O特征的差异表明，要么是不同的来源，要么是深水在其向南的路径上发生了变化。在这些结果的基础上，我们讨论了北大西洋深水形成的概念，这些概念有助于解释北大西洋从盐度驱动的环流模式到温度驱动的环流模式的变化。
Deepwater circulation significantly changed during the last deglaciation from a shallow to a deep-reaching overturning cell. This change went along with a drawdown of isotopically light waters into the abyss and a deep ocean warming that changed deep ocean stratification from a salinity-to a temperature-controlled mode. Yet, the exact mechanisms causing these changes are still unknown. Furthermore, the long-standing idea of a complete shutdown of North Atlantic deepwater formation during Heinrich Stadial 1 (HS1) (17.5–14.6 kyr BP) remains prevalent. Here, we present a new compilation of benthic δ13C and δ18O data from the North Atlantic at high temporal resolution with consistent age models, established as part of the international PAGES working group OC3, to investigate deepwater properties in the North Atlantic. The extensive compilation, which includes 105 sediment cores, reveals different water masses during HS1. A water mass with heavy δ13C and δ18O signature occupies the Iceland Basin, whereas between 20 and 50°N, a distinct tongue of18O depleted,13C enriched water reaches down to 4000 m water depths. The heavy δ13C signature indicates active deepwater formation in the North Atlantic during HS1. Differences in its δ18O signature indicate either different sources or an alteration of the deepwater on its southward pathway. Based on these results, we discuss concepts of deepwater formation in the North Atlantic that help to explain the deglacial change from a salinity-driven to a temperature-driven circulation mode.