Collaborative Research: Fluctuations of the West Antarctic Ice-Sheet in Relation to Lake History in Taylor Valley, Antarctica Since the Last Glacial Maximum

该奖项支持一个研究南极洲泰勒谷表层沉积物地层学的项目。对于泰勒河谷下游的表层沉积物提出了两种截然不同的假设，这两种假设对西南极冰盖(WAIS)如何响应最后一次冰川消融和全新世环境变化的海平面上升具有重要而截然不同的影响。一种假设认为，被命名为罗斯I漂移的沉积物直接反映了罗斯海在退冰期海平面上升期间以及可能受其驱动的10,000个14C年的WAIS收缩。另一种假说认为，泰勒沉积对冰川消融过程中的WAIS变化意义不大。这两个假说反映了对沉积物记录的根本不同的解释。在两个野外季节和在国内机构的第三年期间，该项目将使用冰川地质学、地球化学、100兆赫和400兆赫的探地雷达(GPR)和便携式沉积物取心来检验这两个假设。这项拟议工作的学术价值在于，它将检验这两个假设，并新颖地使用地下记录，这可能会导致对WAIS在冰川消融期间的敏感性的新见解。这项研究还将直接检验在最后一次冰川盛期(LGM)期间，冰川湖沃什伯恩湖比之前提出的要大得多的结论。这一事件，如果是真的，代表了一种令人震惊的气候异常。这些局部冰盖和湖泊问题的答案直接关系到更大范围的问题，涉及海平面上升、气候变化和内部冰盖动力学对全球冰盖年以来WAIS退缩的影响。这个项目有许多更广泛的影响。了解麦克默多海湾地区的冰川和湖泊历史，对于WAIS将在未来海平面和全球气候变化中发挥的作用具有重要意义。此外，泰勒谷的历史对LTER小组目前正在进行的生态系统研究具有重要意义。最后，在拟议的研究过程中，该项目将培养两名研究生和本科生，并将在学生的教学中突出研究的特点。

0540073PrenticeThis award supports a project to examine the stratigraphy of near-surface sediments in Taylor Valley, Antarctica. Two contrasting hypotheses have been proposed for surface sediments in lower Taylor Valley, which have important and very different implications for how the West Antarctic Ice Sheet (WAIS) responded to the sea-level rise of the last deglaciation and Holocene environmental changes. One hypothesis holds that the sediments, designated Ross I drift, directly reflect 10,000 14C-years of WAIS shrinkage in the Ross Sea during and perhaps driven by deglacial sea-level rise. The other hypothesis, holds that the Taylor sediments have little significance for WAIS change during the deglaciation. These two hypotheses reflect fundamentally different interpretations of the sediment record. Over the course of two field seasons and a third year at the home institutions, the project will test these two hypotheses using glacial geology, geochemistry, ground penetrating radar (GPR) at both 100 MHz and 400 MHz, and portable sediment coring. The intellectual merit of the proposed work is that it will test these two hypotheses and make novel use of the subsurface record that may result in new insights into WAIS sensitivity during the deglaciation. The study will also directly test the conclusion that Glacial Lake Washburn was much larger than previously proposed during the Last Glacial Maximum (LGM). This occurrence, if real, represents a stunning climate anomaly. Answers to these local ice sheet and lake questions directly pertain to larger scale issues concerning the influences of sea-level rise, climate change, and internal ice-sheet dynamics on the recession of the WAIS since the LGM. There are numerous broader impacts to this project. Understanding the glacial and lake history in the McMurdo Sound region has important implications for the role that the WAIS will play in future sea-level and global climate change. Moreover, the history of Taylor Valley has significance for the ecosystem studies currently being conducted by the LTER group. Lastly, during the course of the proposed research, the project will train two graduate and undergraduate students and the research will be featured prominently in the teaching of students.