Freshwater influx, hydrographic reorganization and the dispersal of ice‐rafted detritus in the sub‐polar North Atlantic Ocean during the last deglaciation
Freshwater influx, hydrographic reorganization and the dispersal of ice‐rafted detritus in the sub‐polar North Atlantic Ocean during the last deglaciation
复制标题
末次冰消期北大西洋副极地淡水流入、水文重组和冰筏碎屑的扩散
DOI：
10.1002/jqs.2644
复制
发表时间：
2013
影响因子：
2.3
通讯作者：
V. Rinterknecht
中科院分区：
文献类型：
--
作者：
D. Small;W. Austin;V. Rinterknecht
北大西洋东北部的沉积物岩心包含了末次冰消期的高分辨率共记录有孔虫δ18O和冰漂碎屑（IRD）记录。这些揭示了在格陵兰期1d （GI - 1d）时期发生的一次明显的漂流事件，这一特征也出现在北大西洋其他高分辨率岩心中。IRD在冰的远端出现了一个地理上广泛的峰值，而此时流入海洋表面的淡水通量增加被推断为导致了快速冷却，这表明这两个过程之间存在机制联系，类似于新仙女木期（GS‐1）的冷却事件。在GI‐1期间的其他时间，当幸存冰盖的冰山继续向北部地区流动时，南部地区普遍没有IRD，这表明GI‐1d的IRD峰值代表了一个水文重组的时期，改变了IRD的扩散。虽然许多研究表明，淡水通量是最后一次冰川消退期间北大西洋周围观测到的快速气候振荡的主要驱动因素，但本文提出的证据既支持了这一机制，又强调了北大西洋表面水文的快速和重大重组的潜力，以解释独立于冰盖崩解动力学的IRD通量变化。
A sediment core from the north‐east North Atlantic contains high‐resolution co‐registered foraminiferal δ18O and ice‐rafted detritus (IRD) records for the last deglaciation. These reveal a distinct ice‐rafting event that occurred at the time of Greenland Interstade 1d (GI‐1d), a feature also seen in other high‐resolution cores from the North Atlantic. The occurrence of a geographically widespread peak in IRD at ice distal sites at a time when increased freshwater flux to the surface ocean is inferred to have caused rapid cooling suggests a mechanistic link between the processes, analogous to the Younger Dryas (GS‐1) cooling episode. The general absence of IRD at southern locations at other times during GI‐1 when the flux of icebergs from surviving ice sheets to northern locations continued suggests that the GI‐1d IRD peak represents a time of hyrdrographic reorganization which changed IRD dispersal. While numerous studies have suggested freshwater flux as a major driver of rapid climate oscillations observed around the North Atlantic during the last deglaciation, the evidence presented here both supports that mechanism and highlights the potential for rapid and major reorganization of the North Atlantic's surface hydrography to explain changes in IRD flux independently of ice sheet calving dynamics.