Collaborative Reserach: Origin, Timing, and Significance of Millennial-Scale Ice-Rafted Detritus (IRD) Events in the Southern Ocean during the last Ice Age

根据这一奖项，PIS将在高纬度南大西洋(SA)的高沉积速率岩心中研究冰筏碎屑(IRD)。以前的研究已经确定了在最后一次冰川期间12至60KYR之间的六到七个离散的IRD沉积事件，这些事件被认为是区域相关的。如果这些事件能够被证明是广泛分布和同步的，它们可能表明南极冰盖的不稳定。PIS将研究这些南大西洋IRD(SA-IRD)事件的起源，它们对南极冰盖动力学的意义，以及它们与极地冰芯记录的千年尺度气候事件的确切关系。此项目将1。)绘制南大西洋盆地IRD事件的空中分布图；使用AMS-14C计算SA-IRD事件的数据，并使用Th归一化方法估计颗粒通量和沉积物再分布；利用矿物学和地球化学方法追踪IRD事件的起源至其南极源区(S)；将南大西洋IRD事件与南极和格陵兰冰芯、其他海洋沉积岩芯(例如北大西洋)和全球海平面记录相关联。

AbstractUnder this award the PIs will study ice-rafted detritus (IRD) in high-sedimentation-rate cores from the high-latitude South Atlantic (SA). Previos studies have identified six to seven discrete episodes of IRD deposition between 12 and 60 kyr during the last glaciation that have been suggested to be regionally correlative. If these events can be shown to be widely distributed and synchronous, they may indicate instability in Antarctic ice sheets. The PIs will examine the origin of these South Atlantic IRD (SA-IRD) events, their significance for Antarctic ice-sheet dynamics, and their exact relationship to millennial-scale climate events recorded in polar ice cores. This project will 1.) map the aerial distribution of IRD events in the South Atlantic basin; 2.) date SA-IRD events using AMS-14C and estimating particle flux and sediment redistribution using the Th-normalization method; 3.) trace the origin of IRD events to their Antarctic source area(s) using mineralogy and geochemistry; and 4.) correlate South Atlantic IRD events to Antarctic and Greenland ice cores, other marine sediment cores (e.g., North Atlantic), and global sea level records.