Collaborative Research: Chronology of Ice Fluctuations in the South Shetland Islands Since the Last Glacial Maximum

该奖项支持南半球气候变化时间的研究，目的是重建前冰的范围和波动，以及古气候，沿着从温带火地岛到极地南极半岛的关键纬度样带。 现有的样本将使南设得兰群岛（SSI）的冰波动的年代测定成为可能，这是该样带穿过南极辐合带的一个关键位置。令人惊讶的是，关于岛链中以前的冰的范围，几乎没有具体的证据。这项研究的结果将回答一些关于南极半岛冰的范围和随后冰消的时间的基本问题。从乔治王岛和利文斯顿岛精心挑选的冰碛中收集的样本将产生一个宇宙成因的年代年表。 在玛丽安湾外冰碛中发现的一个巨大的花岗闪长岩巨石的初步年龄为18,000年，这表明冰碛可能代表了末次冰期最大冰位。这些数据表明，有可能在SSI中建立一个约20，000年的冰波动记录，这是以前没有实现的。这些数据不仅可以用来解决关于SSI中LGM冰范围的长期争论，而且在评估大气候变化的全球同步性方面也很有价值。研究生和本科生都将参与。这项工作建立在最近成功地测定冰川沉积物在南极洲年轻的300年使用铍-10（10 Be），以及一个意想不到的机会，以映射冰碛和收集在SSI在2002/2003年的确定年龄的样品。这项研究将产生一个新的理解的时间冰波动的SSI，前冰盖的范围和厚度，并可能允许发展的冰川年表从末次冰期到晚全新世。 这项工作还将为气候变化的半球间比较提供基础，并在极地-赤道-极地（PEP 1）样带的限制范围内，在美洲和南极半岛建立高分辨率、日期明确的古气候记录。

This award supports a study of the timing of climate changes in the Southern Hemisphere with the goal of reconstructing former ice extent and fluctuations, as well as paleoclimate, along the key latitudinal transect from temperate Tierra del Fuego to the polar Antarctic Peninsula. Samples already in hand will allow the dating of ice fluctuations in the South Shetland Islands (SSI), a critical location where that transect crosses the Antarctic Convergence. Surprisingly little concrete evidence exists concerning former ice extent in the island chain. The results of this study will answer a number of basic questions regarding ice extent and the timing of subsequent deglaciation in the Antarctic Peninsula. A cosmogenic exposure-age chronology will be produced from samples collected at carefully selected moraines on King George and Livingston Islands. A preliminary age of 18,000 years for a large granodiorite boulder from the outer moraine at Marian Cove suggests that the moraine may represent the Last Glacial Maximum (LGM) ice position. These data point to the potential for developing a ~20,000-yr record of ice fluctuations in the SSI, something that has not been achieved previously. Such data could be used not only to settle the long-standing debate over LGM ice extent in the SSI, but also would be valuable in assessing the global synchrony of large climate changes. Both a graduate and undergraduate student will be involved. This work builds on the recent success in dating glacial deposits in the Antarctic as young as 300 years using Beryllium-10 (10Be), as well as on an unexpected opportunity to map moraines and collect exposure-age samples in the SSI in 2002/2003. This research will produce a new understanding of the timing of ice fluctuations in the SSI, the extent and thickness of former ice cover, and may allow the development of a glacial chronology extending from the LGM to the late Holocene. This work will also provide a basis for inter-hemispheric comparisons of climate change and fits within the constraints of the Pole-Equator-Pole (PEP 1) transect to develop high-resolution, well-dated paleoclimate records in the Americas and Antarctic Peninsula.