Collaborative Research: Controls on Sediment Yields from Tidewater Glaciers from Patagonia to Antarctica

该项目研究了冰川动力学在冰川沉积物产量中的作用。这一结果将揭示冰川侵蚀如何影响造山过程并产生堆积在盆地中的沉积物，这是气候变异性的丰富档案。我们的假设是，侵蚀速度是滑动速度的函数，随着冰川的基础温度降至融点以下，侵蚀速度应该会急剧下降。为了验证这一假设，我们将通过对六个潮水冰川的峡湾沉积物的地震研究来确定沉积物累积速度，这些冰川范围从巴塔哥尼亚快速移动的温带冰川到南极半岛缓慢移动的极地冰川。讨论了每个冰川系统的两个关键主题：1)通过利用地震剖面和岩心数据确定峡湾内的堆积率，从而确定泥沙产量和侵蚀速率；2)每个冰川的动态特性和盆地特征，以寻求冰川侵蚀速率和冰动力学之间的经验关系。这项工作的基础是巴塔哥尼亚和南极半岛，这是用于这些目的的理想自然实验室，因为大纬度范围在相对均匀的岩性和构造环境下提供了大范围的降水和热制度。以前对这些地区的研究指出，南部峡湾的冰川沉积显着减少。这项研究的更广泛影响包括与智利冰川学家和海洋地质学家的跨学科合作，支持一名博士后和三名博士后，将本科生纳入研究，并与地球科学中代表性不足的群体和K-12教育工作者进行接触。该项目的成果还将有助于更好地了解气候与所有高山山脉的演变之间的联系。

This project examines the role of glacier dynamics in glacial sediment yields. The results will shed light on how glacial erosion influences both orogenic processes and produces sediments that accumulate in basins, rich archives of climate variability. Our hypothesis is that erosion rates are a function of sliding speed, and should diminish sharply as the glacier's basal temperatures drop below the melting point. To test this hypothesis, we will determine sediment accumulation rates from seismic studies of fjord sediments for six tidewater glaciers that range from fast-moving temperate glaciers in Patagonia to slow-moving polar glaciers on the Antarctic Peninsula. Two key themes are addressed for each glacier system: 1) sediment yields and erosion rates by determining accumulation rates within the fjords using seismic profiles and core data, and 2) dynamic properties and basin characteristics of each glacier in order to seek an empirical relationship between glacial erosion rates and ice dynamics. The work is based in Patagonia and the Antarctic Peninsula, ideal natural laboratories for these purposes because the large latitudinal range provides a large range of precipitation and thermal regimes over relatively homogeneous lithologies and tectonic settings. Prior studies of these regions noted significant decreases in glaciomarine sediment accumulations in the fjords to the south. As well, the fjords constitute accessible and nearly perfect natural sediment traps.The broader impacts of this study include inter-disciplinary collaboration with Chilean glaciologists and marine geologists, support for one postdoctoral and three doctoral students, inclusion of undergraduates in research, and outreach to under-represented groups in Earth sciences and K-12 educators. The results of the project will also contribute to a better understanding of the linkages between climate and evolution of all high mountain ranges.