Chronology of the West Antarctic Ice Sheet: New Evidence from Marie Byrd Land Nunataks

0087709Kurz该奖项支持一个项目，该项目以实验室为基础，详细研究收集在Waesche山侧翼的冰川冰碛巨石，Waesche山是南极洲西部玛丽伯德地执行委员会山脉的一个冰峰。对这些样品的初步研究结果是测量了西南极洲内陆过去的冰盖高度。这里需要资金来测量冰碛和邻近火山基岩的剩余样本的暴露年龄。该项目的目标是结合野外观测、地表暴露测年（氦-3、氖-21和氯-36）和氩-40/氩-39测年来确定南极西部冰盖（WAIS）过去的海拔高度。最初的研究表明，冰碛记录了过去较高的冰位，冰碛是由退去的冰留下的火山碎片组成的，氦-3和氯-36表面暴露年代可以用来限制过去冰位的时间。预计这些分析将完善有关最后一次冰川消融的初步结果，并提供早期冰盖高度的独特记录。主要的长期目标是提供10 kA以前WAIS内部古冰川的年代学和海拔数据。Waesche山地表冰高度的独特记录为冰盖的行为及其对气候和海平面变化的响应提供了关键的约束。这一信息将有力地帮助我们确定为什么在最后一次冰期和之前的间冰期WAIS的行为是这样的，并将有助于预测它在未来将如何变化。

0087709Kurz This award supports a project for a detailed laboratory-based study of glacial moraine boulders collected on the flank of Mt. Waesche, a nunatak in the Executive Committee Range, Marie Byrd Land, West Antarctica. Preliminary work on these samples resulted in measurement of past ice sheet elevations in interior West Antarctica. Funds are requested here to measure exposure ages in the remaining samples from the moraine and adjacent volcanic bedrock. The goal is to use a combination of field observations, surface exposure dating (Helium-3, Neon-21 and Chlorine-36) and Argon-40/Argon-39 dating to constrain past elevations of the West Antarctic ice sheet (WAIS). The initial study demonstrated that higher past ice levels are recorded by moraines, composed of volcanic debris left behind by receding ice, and that Helium-3 and Chlorine-36 surface exposure dating can be used to constrain the timing of past ice high stands. It is expected that these analyses will refine the initial results pertaining to the last deglaciation and provide a unique record of earlier ice sheet elevations. The primary long-term objective is to provide chronological and elevation data of the paleoglaciology of the interior of the WAIS prior to 10 kA. The unique record of surface ice elevations at Mt. Waesche provides key constraints on the behavior of the ice sheet and its response to climate and sea level change. This information will contribute strongly to determining why the WAIS behaved as it did during the last deglaciation and the previous interglacial, and will help efforts to predict how it will change in the future.