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: 1714875
• 负责人: Eric Sandvol
• 金额: $ 40.71万
• 依托单位: University of Missouri-Columbia
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1714875&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.

该项目涉及对一个鲜为人知的独特地质环境的研究：一个拥有大量沉积物的俯冲带，恒河-雅鲁藏布江三角洲（GBD）。GBD是世界上沉积物积聚最极端的例子，孟加拉盆地的沉积物厚达19公里。与其他俯冲带相比，该地区火山活动较少，地震风险较大；最近的GPS结果表明，这个高度倾斜的板块边界被锁定，可能发生8.2级地震，可能影响超过1.4亿人。该项目的动机是研究极端沉积如何影响俯冲现象。该项目将涉及来自孟加拉国、印度和缅甸、新加坡、挪威和美国的科学家的多机构、多国合作。PIs将重点关注三个主要问题：1)新近纪增生棱镜的生长和地震危险；2)印缅山脉和缅甸盆地的地壳缩短与变形；3)流入流体含量与火山作用。为了解决这些问题，他们将在孟加拉国-印度-缅甸阵列（BIMA）从变形前沿到弧后的样带中部署地震、GPS、大地电磁和重力传感器。构造地质学、地球化学和热年代学将提供额外的限制。他们将使用广泛的数值和实验室建模程序来整合和解释来自多个数据集的结果。这种极端沉积物俯冲的端元案例对于理解所有俯冲带的这些问题具有广泛的意义。