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

该奖项支持了一个项目，该项目记录了Mercer冰流（原冰流a）头部附近俄亥俄山脉的南极西部冰盖（WAIS）的前高地和稳定性评估。该领域的位置位于“瓶颈”，一个独特的，相对狭窄的通道在横贯南极山脉连接南极西部和东部冰盖。该地点位于冰分水岭附近，因此可以很好地确定过去的内部冰高度。这项研究将包括对冰川沉积物和侵蚀特征进行地质测绘，并结合俄亥俄山脉冰暴的宇宙成因地表暴露年代测定，以确定过去较高冰盖水平和当地冰川波动的年代学。在当前冰面以上60米的新冰川不稳定物的暴露年龄将用于限制该地区最后一次高水位和随后WAIS下降的时间。冰盖表面碎屑带的暴露年龄将限制当前海拔附近连续冰盖的持续时间。还将从当地冰川冰碛的年表中获得一个免费的当地代用气候记录。从拟议的研究中获得的数据将有助于开发在2万年前末次冰川高峰时期和之后的随时间变化的非平衡WAIS模式，这是南极西部冰盖倡议的一个主要目标。从这个靠近默瑟冰流源头的关键位置对冰盖海拔高度进行年龄控制，将完成从罗斯海的冰河时代终点，经过麦克默多湾和南南极横贯山脉，到冰分水岭附近的起始区域的年代学覆盖。此外，瓶颈期的冰川地质记录将反映WAIS与EAIS相互作用的历史，可用于验证WAIS更新世崩塌的假设。由于其与海平面的联系，WAIS的未来行为引起了社会的极大兴趣。南极冰盖融化将导致海平面上升，对生活在世界海岸附近的大部分人口产生负面影响。该研究旨在为冰盖建模界提供有关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，拟议的研究结合了研究生和本科生的教育，并使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