EAR-PF: Channel network evolution in a tectonically active basin enlightened through innovative luminescence geochronology

EAR-PF：通过创新的发光地质年代学启发构造活动盆地中的河道网络演化

• 批准号: 1855264
• 负责人: Elizabeth Chamberlain
• 金额: $ 8.7万
• 依托单位: Chamberlain Elizabeth L
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1855264&HistoricalAwards=false
• 关键词: EAR; PF; Channel; network; evolution

Dr. Elizabeth L. Chamberlain has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at Columbia University, Vanderbilt University, and Wageningen University. The project will make use of recent innovations by Dr. Chamberlain regarding optically stimulated luminescence (OSL) dating. OSL estimates the time of sediment deposition based on trapped charges that accumulate in quartz grains when they are removed from sunlight. She will apply OSL to the Ganges-Brahmaputra Delta, Bangladesh, to determine the mechanisms and timescales of delta evolution. Specifically, this work will explore the connection between river and seismic (earthquake) processes in a large delta. Findings will describe sediment delivery to floodplains and coasts, a key factor in sustaining deltas under accelerated rates of sea-level rise. In addition, the research will provide new information about river-seismic geohazards by investigating how often large earthquakes occur and whether earthquakes are capable of forcing rivers to spontaneously change course. The anticipated findings are relevant to coastal management within the densely populated nation of Bangladesh and in other coastal regions worldwide such as the Mississippi Delta, U.S. This work will also contribute to methodological development of the OSL tool. The research will facilitate knowledge transfer between work groups in the U.S., The Netherlands, and Bangladesh and will support student education by engaging Bangladeshi M. Sci. students in field work and a U.S. undergraduate in laboratory work. The Ganges-Brahmaputra Delta offers a rare opportunity to explore coupled fluvial-tectonic processes, given its extensive river channel network and position along several actively deforming plate boundaries. In 2018, Dr. Chamberlain and colleagues identified a cluster of paleo-seismite structures in the Late Holocene Ganges floodplain that include large sand dikes and soft sediment deformation. Located on the edge of an immense (1.5 km-wide) relict and underfilled channel scar, these features suggest a link between large seismic events and major channel avulsions. Dr. Chamberlain will use her recently published OSL protocol to date seismite, paleochannel bed and fill, point bar, and adjacent floodplain deposits, thereby testing two processes that may regulate the avulsion timescales of large rivers: (1) enhanced avulsion frequency through forcing by large, high-magnitude seismic events, and (2) suppressed avulsion frequency through aggradation of the delta plain fed by small distributary channels. A component of this investigation will explore the development of novel luminescence geochronology approaches to determine the timing of sand-dike emplacement. Dr. Chamberlain's research will contribute to both the theoretical and applied knowledge of delta dynamics, and to the advancement of luminescence tools by providing a new method to date structures previously not amenable to dating.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.

Elizabeth L.博士张伯伦已被授予国家科学基金会博士后奖学金，在哥伦比亚大学，范德比尔特大学和瓦赫宁根大学进行研究和教育计划。该项目将利用张伯伦博士最近关于光释光（OSL）测年的创新。OSL估计沉积物沉积时间的基础上捕获的电荷积累在石英颗粒时，他们从阳光下删除。她将应用OSL到孟加拉国的恒河-雅鲁藏布江三角洲，以确定三角洲演化的机制和时间尺度。具体来说，这项工作将探讨河流和地震（地震）过程之间的连接在一个大三角洲。调查结果将描述沉积物输送到洪泛区和海岸，这是在海平面上升速度加快的情况下维持三角洲的关键因素。此外，该研究还将通过调查大地震发生的频率以及地震是否能够迫使河流自发改变航向，提供有关河流地震地质灾害的新信息。预期的结果是相关的沿海管理人口稠密的国家孟加拉国和世界其他沿海地区，如密西西比三角洲，美国这项工作也将有助于OSL工具的方法发展。这项研究将促进美国工作组之间的知识转移，荷兰和孟加拉国，并将通过聘请孟加拉国M。Sci.学生在实地工作和美国本科生在实验室工作。恒河-雅鲁藏布江三角洲提供了一个难得的机会，探讨耦合的河流构造过程，因为它的广泛的河道网络和位置沿着几个积极变形的板块边界。2018年，张伯伦博士及其同事在晚全新世恒河泛滥平原发现了一组古震积岩结构，其中包括大型砂堤和软沉积物变形。位于一个巨大的（1.5公里宽）残留和欠填充的通道疤痕的边缘，这些功能表明大地震事件和主要通道撕脱之间的联系。Chamberlain博士将使用她最近发表的OSL协议来确定震积岩、古河道床和填充物、点坝和相邻洪泛平原沉积物的日期，从而测试可能调节大河撕脱时间尺度的两个过程：（1）通过大型高震级地震事件的强迫增强撕脱频率，以及（2）通过由小分流河道供给的三角洲平原的沉积抑制撕脱频率。这项调查的一个组成部分将探索新的发光地质年代学方法的发展，以确定砂堤就位的时间。Chamberlain博士的研究将有助于三角洲动力学的理论和应用知识，并通过提供一种新的方法来确定以前不适合测年的结构，从而促进发光工具的发展。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

A geoarchaeological perspective on the challenges and trajectories of Mississippi Delta communities

• DOI: 10.1016/j.geomorph.2020.107132
• 发表时间: 2020-03
• 期刊: Geomorphology
• 影响因子: 3.9
• 作者: E. Chamberlain;J. Mehta;T. Reimann;J. Wallinga

Does Load‐Induced Shallow Subsidence Inhibit Delta Growth?

负荷引起的浅沉降是否会抑制三角洲增长？

• DOI: 10.1029/2021jf006153
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Earth Surface
• 作者: Chamberlain, E. L.;Shen, Z.;Kim, W.;McKinley, S.;Anderson, S.;Törnqvist, T. E.
• 通讯作者: Törnqvist, T. E.

Integrating geochronologic and instrumental approaches across the Bengal Basin

• DOI: 10.1002/esp.4687
• 发表时间: 2019-11
• 期刊: Earth Surface Processes and Landforms
• 影响因子: 3.3
• 作者: E. Chamberlain;S. Goodbred;R. Hale;M. Steckler;J. Wallinga;Carol A. Wilson