Collaborative Research: Subduction below extreme sedimentation - A multidisciplinary transect from the Ganges-Brahmaputra Delta to the IndoBurma Backarc

合作研究：极端沉积作用下的俯冲——从恒河-雅鲁藏布江三角洲到印缅弧后的多学科横断面

• 批准号: 1714755
• 负责人: Doug Prose
• 金额: $ 18.5万
• 依托单位: EARTH IMAGES FOUNDATION
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1714755&HistoricalAwards=false
• 关键词: Collaborative; Research; Subduction; below; extreme

This project involves a study of a poorly understood and unique geologic setting: a subduction zone that has an exceptionally large amount of sediment, the Ganges-Brahmaputra Delta (GBD). The GBD is the world's most extreme example of sediment accretion, with sediments up to 19 km thick in the Bengal Basin. The region has little volcanism compared to other subduction zones and a large seismic risk; recent GPS results indicate that this highly oblique plate boundary is locked with the potential for a M8.2 earthquake that could affect more than 140 million people. The project is motivated by the question of how the extreme sedimentation affects subduction phenomena. The project will involve a multi-institution, multi-nation collaboration involving scientists from Bangladesh, India and Myanmar, Singapore, Norway, and the U.S.The PIs will focus on three major issues: 1) Neogene growth of the accretionary prism and earthquake hazard; 2) Crustal shortening and deformation across the IndoBurma Ranges and Burma Basin; and 3) Incoming fluid content and volcanism. To address these issues, they will deploy seismic, GPS, magnetotellurics and gravity sensors in a transect from the deformation front to the backarc in the Bangladesh-India-Myanmar Array (BIMA). Structural geology, geochemistry and thermochronology will provide additional constraints. They will use a broad program of numerical and laboratory modeling to integrate and interpret the results from the multiple data sets. This end-member case of extreme sediment subduction has broad implications for understanding these issues at all subduction zones.

该项目涉及一项对知名度不佳和独特的地质环境的研究：一个俯冲带，具有大量沉积物，即恒河 - 布拉马普特拉三角洲（GBD）。 GBD是世界上最极端的沉积物积聚例子，在孟加拉盆地中，沉积物厚19公里。与其他俯冲区相比，该地区几乎没有火山，而且地震风险很大。最近的GPS结果表明，这种高度倾斜的板边界被锁定，可能会影响超过1.4亿人的M8.2地震。 该项目的激励是由极端沉积如何影响俯冲现象的问题。该项目将涉及多国，跨国合作，涉及孟加拉国，印度和缅甸，新加坡，挪威的科学家，美国将重点介绍三个主要问题：1）增生性棱镜和地震危险的新近属增长； 2）在整个底腹范围和缅甸盆地上的地壳缩短和变形； 3）传入的流体含量和火山。为了解决这些问题，他们将在从变形前到孟加拉国 - 印度 - 墨西哥阵列（BIMA）的横层中部署地震，GPS，Magnetoteltelurics和Gravity传感器。结构地质，地球化学和热量学将提供其他约束。他们将使用广泛的数值和实验室建模程序来整合和解释多个数据集的结果。这种最终成员的极端沉积物俯冲案例对在所有俯冲区域中理解这些问题具有广泛的意义。