Collaborative Research: West Antarctic Ice Sheet Stability: The Glacial Geologic Record from the Ohio Range of the Horlick Mountains in the Bottleneck

该奖项支持一个项目，以记录以前的高位并评估靠近美世冰流(前冰流A)源头的俄亥俄州山脉西南极冰盖(WAIS)的稳定性。该油田位于“瓶颈”地带，这是横贯南极山脉的一条独特的相对狭窄的通道，连接着南极西部和东部的冰盖。该位置靠近冰的分水岭，因此能够很好地确定过去的内部冰层高度。这项研究将涉及冰川沉积和侵蚀特征的地质测绘，结合俄亥俄州山脉纽纳塔克的宇宙成因表面暴露年代，以确定过去较高冰盖水平和当地冰川波动的年代学。新的冰川不稳定的暴露年龄，高出目前冰面60米，将被用来限制最后一个高位的时间，以及随后该地区WAIS的下降。冰盖表面碎片带的暴露年龄将限制目前海拔附近连续冰盖的持续时间。还将从当地冰川冰川的年表中获得免费的当地代理气候记录。拟议研究获得的数据将有助于建立20,000年前最后一次冰川高峰期及自那以来的WAIS随时间变化的非平衡模型，这是西南极冰盖倡议的主要目标。从这个靠近美世冰流源头的关键位置对冰盖高度进行年龄控制，将完成从罗斯海的冰河时代终点、穿过麦克默多海峡和南横贯北极山脉到冰川分水岭附近的起始区的年代覆盖。此外，瓶颈区的冰川地质记录将反映WAIS和EAIS相互作用的历史，这可以用来检验WAIS更新世崩溃的假说。由于其与海平面的联系，WAIS的未来行为引起了社会的极大关注。南极冰盖的融化将提高海平面，对生活在世界海岸附近的大部分人口产生负面影响。这项研究的目的是向冰盖模型界提供关于WAIS过去历史的必要数据，以便准确预测冰盖的未来行为。此外，拟议的研究包括研究生教育和本科生教育，并让他们参与具有社会意义的目标的研究。

This award supports a project to document former high stands and assess the stability of the West Antarctic ice sheet (WAIS) at the Ohio Range near the head of Mercer Ice Stream (formerly Ice Stream A). The field location is situated in the "Bottleneck", a unique, relatively narrow passage in the Transantarctic Mountains connecting the West and East Antarctic ice sheets. The location lies near the ice divide and is thus well situated to determine past interior ice elevation. The research will involve geologic mapping of glacial deposits and erosion features combined with cosmogenic surface exposure dating on the Ohio Range nunataks to determine the chronology of past higher ice sheet levels and local glacier fluctuations. Exposure ages of fresh glacial erratics, up to 60 m above the present ice level will be used to constrain the timing of the last high stand and subsequent draw down of the WAIS in this sector. Exposure ages of debris bands on the ice sheet surface will constrain the duration of continuous ice cover near the present elevation. A complimentary local proxy climate record will also be obtained from a chronology of the local glacier moraines. Data obtained from the proposed research will contribute to the development of time-dependent, non-equilibrium models of the WAIS, at and since the last glacial maximum 20,000 years ago, a major objective of the West Antarctic Ice Sheet Initiative. Age control on ice sheet elevation from this key location, near the head of the Mercer Ice Stream, will complete chronologic coverage extending from the ice age terminus in the Ross Sea, through McMurdo Sound and the southern Transantarctic Mountains, to the onset area near the ice divide. In addition, the glacial geologic record in the Bottleneck will reflect the history of the interaction of WAIS and EAIS, which could be used to test hypotheses of Pleistocene collapse of the WAIS. The future behavior of the WAIS is of significant interest to society because of its linkage to sea level. Melting of Antarctic ice sheets would raise sea levels, negatively impacting the large portion of the human population living near the world's coasts. The research is designed to provide necessary data on the past history of the WAIS to the ice sheet modeling community in order to accurately predict the future behavior of the ice sheet. In addition, the proposed research incorporates both graduate and undergraduate student education and involves them in research with goals that are of societal significance