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NSF-BSF: Collaborative research: The Processes and feedbacks that induce multi-scale interactions between local divide migration, drainage reversal and escarpment evolution

NSF-BSF：合作研究：引起局部鸿沟迁移、排水逆转和悬崖演化之间多尺度相互作用的过程和反馈

基本信息

批准号：
1946253
负责人：
eitan shelef
金额：
$ 29.22万
依托单位：
University of Pittsburgh
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-01-15 至 2024-12-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1946253&HistoricalAwards=false
关键词：
NSF BSF Collaborative research Processes

项目摘要

The structure of river networks impacts the spatial distribution of elevation, water, and life across Earth’s surface. Interestingly, this structure changes through time by movement of the water divides that separate river basins. The divide migration process occurs at the local hillslope scale but the driving forces for it are rooted in large scale tectonic and climatic changes. Furthermore, local processes of divide migration influence the broader geomorphic, hydrologic, and ecologic functionality of the Earth’s surface. The proposed research explores the mechanisms through which these multi-scale processes occur. More specifically, how local topographic, hydrologic, and lithologic conditions lead to a cascade of feedbacks that can ultimately have a large scale impact on the Earth system. This binational project compares and contrasts arid and humid research sites in Israel and the USA, respectively, and will thus strengthen research collaboration between the two countries. The research team will also develop and lead an enhanced science education program for K6-8 students in schools in Pennsylvania and Colorado, including schools with high attendance of underrepresented populations.Water divides play a critical role in controlling the form of landscapes and shaping hydrologic and geomorphic functionality. The mobility of water divides is inherently related to the local hillslope and fluvial processes that control the adjacent relief. At the same time, divide mobility leads to reorganization of the drainage network, which significantly influence large-scale topographic, isostatic, and stratigraphic patterns. At present, the processes and feedbacks by which local hillslope and fluvial regimes interact with basin-scale drainage reorganization and with large scale topographic and isostatic changes remain generally unexplored. To address these knowledge gaps, this research focuses on the juxtaposition of topographic escarpments and reversed channels (an end-member of reorganization), where the initial conditions for divide migration are relatively well constrained. In this setting, the topology and sediments of the reversed channels record the history of divide migration. These channels preserve evidence for how local lithologic and hydrologic conditions act as a tipping point that drives the system into a cascading response that results in drainage reorganization, topographic changes and potentially isostatic adjustments. To explore the generality of these processes, the investigators will compare and contrast the emerging landscape dynamics in both arid and humid field sites in Israel and the USA, respectively, across different lithologic and tectonic settings. They will use field mapping and topographic analyses, in conjunction with landscape evolution models and geochronological analyses to constrain the controlling parameters and the rates associated with different processes of divide migration, flow reversals, and the evolution of escarpments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

河流网络的结构影响着整个地球表面的海拔、水和生命的空间分布。有趣的是，这种结构随着时间的推移而变化，因为分开河流流域的水的运动。分水岭迁移过程发生在局部山坡尺度上，但其驱动力来源于大尺度的构造和气候变化。此外，分水岭迁移的局部过程影响到地球表面更广泛的地貌、水文和生态功能。这项拟议的研究探索了这些多尺度过程发生的机制。更具体地说，当地的地形、水文和岩性条件如何导致一连串的反馈，最终可能对地球系统产生大规模影响。该两国项目分别对以色列和美国的干旱和潮湿研究地点进行了比较和对比，从而将加强两国之间的研究合作。该研究小组还将为宾夕法尼亚州和科罗拉多州学校的K6-8学生开发和领导一个增强的科学教育计划，包括那些出勤率较低的人口的学校。分水岭在控制景观的形式和塑造水文和地貌功能方面发挥着关键作用。分水岭的流动性与控制邻近地貌的当地山坡和河流过程有着内在的联系。与此同时，分水岭的流动导致了水系的重组，这对大尺度的地形、均衡和地层格局产生了重大影响。目前，局部山坡和河流系统与盆地尺度的水系重组以及大尺度地形和均衡变化相互作用的过程和反馈普遍仍未被探索。为了解决这些知识差距，本研究侧重于地形悬崖和反向通道(重组的最终成员)的并置，其中分流迁移的初始条件受到相对较好的限制。在这种背景下，反向河道的地形和沉积记录了分流运移的历史。这些渠道保存了当地岩性和水文条件如何作为引爆点的证据，推动系统进入级联反应，导致排水重组、地形变化和潜在的均衡调整。为了探索这些过程的共性，研究人员将在不同的岩性和构造环境下，分别比较和对比以色列和美国干旱和潮湿地区的新出现的景观动态。他们将使用现场测绘和地形分析，结合景观演变模型和地质年代学分析，以限制与分水岭迁移、水流逆转和悬崖演变的不同过程相关的控制参数和速率。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。