Collaborative research: Is Anthropocene sedimentation in valley bottoms a geologically significant event?

合作研究：人类世谷底沉积是一个具有重大地质意义的事件吗？

• 批准号: 1451586
• 负责人: Dorothy Merritts
• 金额: $ 13.79万
• 依托单位: Franklin and Marshall College
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2018-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1451586&HistoricalAwards=false
• 关键词: Collaborative; research; Anthropocene; sedimentation; valley

Non-technical description of the project's broader significance and importanceRecent research in geomorphology, the study of Earth's surface and the processes that shape it, has found that human modification of land in the northeastern U.S. over the past few centuries has resulted in large volumes of sediment being eroded from hillsides and deposited in valleys along rivers and streams. Prior research has suggested that this sediment transfer is the most important modification of Earth's landscape in tens of thousands of years. This project will evaluate the significance of these deposits on a regional scale by carefully measuring them in representative field locations and then using newly available high-resolution topographic data to extrapolate the findings to whole watersheds and regions. Knowledge of how human activities have contributed to landscape change is a prerequisite for informed land-management and restoration decisions. To ensure broad communication of project findings, the researchers will interact with policy makers, planners, government agencies, and non-profit organizations interested in stream and wetland conservation. This project also will include strong opportunities for student research, since the collaborating institutions are heavily invested in undergraduate education as a priority.Technical description of the project Recent global sedimentation studies demonstrate that rates of erosion due to human activities exceed the amount of sediment delivered to the oceans by rivers. At the same time, field-based studies at the channel to watershed scale have found large quantities of sediment stored in valley bottoms during the past few centuries. This project will bridge the gap between global and watershed-based approaches by quantifying the amount of Anthropocene (recent, human related) sediment stored in valley bottoms of the northeastern United States, and then comparing this amount to published volumes and timescales of (1) erosion from the landscape, and (2) deposition in reservoirs, lakes, and estuaries along the Atlantic margin. The research will use high-resolution topographic data to map the extent and thickness of this fill over large spatial areas (1,000-10,000 square km), and will test these methods using fieldwork (mapping, coring, geophysical data collection, sediment sampling and dating) in key watersheds. A central goal is to evaluate the extent to which sediment storage in the unglaciated mid-Atlantic region applies in the glaciated, less-studied New England region, where upland soils are thin, sediment sources are generally localized to glacial deposits, and large natural lakes and wetlands provide terrestrial accommodation space. The results of the project will help resolve the discrepancy between erosion and deposition rates at small spatial (watershed) and temporal (decadal to centennial) scales versus the rates that occur globally and over geological time.

对该项目更广泛的意义和重要性的非技术描述最近的地貌学研究、对地球表面及其形成过程的研究发现，过去几个世纪人类对美国东北部土地的改造导致大量沉积物从山坡上被侵蚀并沉积在沿着河流和溪流的山谷中。先前的研究表明，这种沉积物转移是数万年来地球景观最重要的变化。该项目将在区域范围内评价这些矿床的重要性，方法是在有代表性的实地地点仔细测量这些矿床，然后利用新获得的高分辨率地形数据将结果外推到整个流域和区域。了解人类活动如何促成地貌变化是作出知情的土地管理和恢复决定的先决条件。为了确保项目结果的广泛传播，研究人员将与政策制定者，规划者，政府机构和对河流和湿地保护感兴趣的非营利组织进行互动。该项目还将为学生提供大量的研究机会，因为合作机构将本科教育作为优先事项进行大量投资。项目技术说明最近的全球沉积研究表明，人类活动造成的侵蚀速度超过了河流向海洋输送的沉积物量。与此同时，在流域尺度上对河道进行的实地研究发现，在过去几个世纪里，谷底储存了大量沉积物。该项目将通过量化储存在美国东北部山谷底部的人类世（近期，与人类有关）沉积物的数量，然后将该数量与已公布的（1）景观侵蚀量和（2）大西洋边缘沿着水库、湖泊和河口沉积量和时间尺度进行比较，弥合全球方法和基于流域的方法之间的差距。这项研究将利用高分辨率地形数据绘制大面积（1 000 - 10 000平方公里）的这种填充物的范围和厚度，并将在关键流域通过实地工作（绘图、取芯、地球物理数据收集、沉积物取样和测年）测试这些方法。一个中心目标是评估在何种程度上适用于在冰川，研究较少的新英格兰地区，高地土壤薄，沉积物来源一般局限于冰川沉积物，大型天然湖泊和湿地提供陆地的住宿空间，沉积物存储在未冰川化的大西洋中部地区。该项目的结果将有助于解决小的空间（流域）和时间（十年至百年）尺度上的侵蚀和沉积速率与全球和地质时期的侵蚀和沉积速率之间的差异。