Accelerated drawdown of meridional overturning in the late-glacial Atlantic triggered by transient pre-H event freshwater perturbation
Accelerated drawdown of meridional overturning in the late-glacial Atlantic triggered by transient pre-H event freshwater perturbation
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DOI：
10.1029/2006gl026239
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发表时间：
2006-08-31
影响因子：
5.2
通讯作者：
Edwards, R. L.
中科院分区：
文献类型：
--
作者：
Hall, I. R.;Moran, S. B.;Edwards, R. L.
[1]晚更新世期间大西洋纬向翻转环流（MOC）的突然减少与冰川淡水的灾难性排放直接相关，引发了向北海洋热量输送的中断，并导致全球气候变化。在这里，我们提供的测量过量沉积Pa-231/Th-230从高积累沉积物漂移存款在东北大西洋，记录了一系列的突然变化的MOC率，相关的深海通风和海洋表面气候。该数据系列揭示了一个连续的减少MOC率在类似的18.0万年BP前，恰好只有短暂的和本地化的淡水输入。这一变化代表了一个实质性的，但不是全部的，停止在MOC的主要海因里希（H1）融水事件之前至少1,200年。这些结果突出了有针对性的淡水扰动在促进实质性MOC变化方面的潜力，而与灾难性淡水激增没有直接联系。
[1] Abrupt decreases of the Atlantic meridional overturning circulation (MOC) during the Late Pleistocene have been directly linked to catastrophic discharges of glacimarine freshwater, triggering disruption of northward marine heat transport and causing global climate changes. Here we provide measurements of excess sedimentary Pa-231/Th-230 from a high-accumulation sediment drift deposit in the NE Atlantic that record a sequence of sudden variations in the rate of MOC, associated deep ocean ventilation and surface-ocean climatology. The data series reveal a sequential decrease in the MOC rate at similar to 18.0 ka BP ago that coincides with only transient and localized freshwater inputs. This change represents a substantial, though not total, cessation in MOC that predates the major Heinrich (H1) meltwater event by at least 1,200 years. These results highlight the potential of targeted freshwater perturbations in promoting substantial MOC changes without a direct linking with catastrophic freshwater surges.