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

该项目考察了冰川动力学在冰川沉积物产量中的作用。研究结果将揭示冰川侵蚀如何影响造山过程，并产生沉积在盆地中的沉积物，这是气候变化的丰富档案。我们的假设是，侵蚀率是滑动速度的函数，当冰川的基础温度降到熔点以下时，侵蚀率应该会急剧下降。为了验证这一假设，我们将从六个潮汐冰川的峡湾沉积物的地震研究中确定沉积物堆积率，这些冰川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。每个冰川系统都解决了两个关键主题：1)通过使用地震剖面和核心数据确定峡湾内的积累速率来确定沉积物产量和侵蚀速率；2)每个冰川的动力特性和盆地特征，以寻求冰川侵蚀速率和冰动力学之间的经验关系。这项工作是基于巴塔哥尼亚和南极半岛，理想的自然实验室为这些目的，因为大的纬度范围提供了大范围的降水和热制度相对均匀的岩性和构造环境。先前对这些地区的研究指出，南部峡湾的冰川期海洋沉积物堆积显著减少。此外，峡湾还构成了可接近的、近乎完美的天然沉积物陷阱。这项研究的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，为一名博士后和三名博士生提供支持，将本科生纳入研究，并向地球科学和K-12教育工作者中代表性不足的群体提供服务。该项目的结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.