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.

该项目更广泛意义和重要性的非技术描述最近的地貌学研究，即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了大量沉积物的产生从山坡上被侵蚀并沉积在河流和溪流沿岸的山谷中。先前的研究表明，这种沉积物转移是数万年来对地球景观最重要的改变。该项目将通过在代表性的实地位置仔细测量这些沉积物，然后使用新获得的高分辨率地形数据将研究结果外推到整个流域和区域，来评估这些沉积物在区域范围内的重要性。了解人类活动如何导致景观变化是做出明智的土地管理和恢复决策的先决条件。为了确保项目研究结果的广泛交流，研究人员将与对溪流和湿地保护感兴趣的政策制定者、规划者、政府机构和非营利组织进行互动。该项目还将为学生研究提供大量机会，因为合作机构将大量投资于本科教育作为优先事项。该项目的技术说明最近的全球沉积研究表明，人类活动造成的侵蚀率超过了输送到地球的沉积物量。海洋与河流。与此同时，从河道到流域规模的实地研究发现，在过去的几个世纪里，谷底储存了大量沉积物。该项目将通过量化美国东北部谷底储存的人类世（近期的、与人类相关的）沉积物数量，然后将这一数量与已发布的数量和时间尺度进行比较，来弥合全球方法和基于流域的方法之间的差距。地貌侵蚀；(2) 大西洋边缘水库、湖泊和河口的沉积。该研究将使用高分辨率地形数据来绘制大空间区域（1,000-10,000平方公里）内填充物的范围和厚度，并将通过现场工作（绘图、取芯、地球物理数据收集、沉积物采样和年代测定）来测试这些方法）在关键流域。一个中心目标是评估非冰川期大西洋中部地区的沉积物储存在多大程度上适用于冰川期、研究较少的新英格兰地区，该地区的高地土壤很薄，沉积物来源通常局限于冰川沉积物和大型天然湖泊湿地提供陆地住宿空间。该项目的结果将有助于解决小空间（流域）和时间（十年到百年）尺度的侵蚀和沉积速率与全球和整个地质时期发生的速率之间的差异。