Deciphering 6 My of the Greenland Ice Sheet History using in situ 10-Be from marine sediment cores

这项研究将探索一种新的方法，通过测量海洋钻探计划先前在格陵兰岛南部和东部收集的沉积物岩心中的宇宙成因同位素铍-10，来破译格陵兰岛冰盖在上新世和更新世的历史。铍-10是由裸露岩石中的宇宙射线产生的。这项调查的前提是，Be-10积累在冰盖退缩的时候，在冰盖生长的时候，侵蚀和沉积在海洋沉积物的表层岩石。同位素时间序列将包括更新世和上新世沉积物，可追溯到400万至600万年前，可能超过格陵兰大陆规模冰川作用的开始。研究人员希望1）限制格陵兰岛大陆冰川开始的时间，2）估计冰盖的相对面积范围，3）确定冰盖的侵蚀力和沉积物运输效率，以及4）限制格陵兰岛在冰川开始之前的侵蚀速率。了解格陵兰冰盖过去的动态（特别是冰川消退的程度和再生长的时间尺度）是了解冰盖未来可能表现的关键。该项目的核心部分是培训一名年轻的博士后研究助理，两名本科生也将参与该项目。

This research will explore a new method of deciphering the history of the Greenland Ice Sheet over the Pliocene and Pleistocene by measuring the cosmogenic isotope beryllium-10 in sediment cores previously collected off southern and eastern Greenland by the Ocean Drilling program. Beryllium-10 is produced by cosmic rays in exposed rock. The premise of this investigation is that Be-10 accumulates in surface rock during times of ice-sheet retreat and is eroded and deposited in marine sediment during times of ice-sheet growth. The isotopic time series will include Pleistocene and Pliocene sediment stretching back 4 to 6 million years, possibly beyond the onset of continental-scale glaciation in Greenland. The investigators hope to 1) constrain the time at which continental glaciation on Greenland began, 2) estimate the relative areal extent of the ice sheet through time, 3) determine the erosivity and sediment transport efficiency of the ice sheet, and 4) constrain the erosion rate of Greenland prior to the onset of glaciation. Understanding Greenland Ice Sheet dynamics in the past (particularly the extent of deglaciation and the timescale of regrowth) is key to understanding how the ice sheet might behave in the future. A central part of the project is the training of a young postdoctoral research associate, and two undergraduate students will work on the project as well.