Variations in Deformation and Kinematics Along and Across the Himalayan Arc through Time: Insights from the Darjeeling-Sikkim-Tibet Transect

喜马拉雅弧沿线和横跨喜马拉雅弧的变形和运动学随时间的变化：来自大吉岭-锡金-西藏横断面的见解

• 批准号: 0439999
• 负责人: Gautam Mitra
• 金额: $ 20.1万
• 依托单位: University of Rochester
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0439999&HistoricalAwards=false
• 关键词: Variations; Deformation; Kinematics; Along; Across

The Himalayan mountain belt is the result of continent - continent collision between the Indian and Eurasian tectonic plates that started 50-55 million years ago and is continuing to the present day. A significant portion of the total ~650 km plate convergence went to forming shortening structures in the Himalayan ranges. Because of the arcuate form of the Himalayas shortening varies along its length. The amounts of shortening have previously only been documented in the western Himalayas (Kashmir, Kumaon, Nepal). This project is undertaking a pair of detailed transects along the Tista drainage (~89 degrees East longitude), to fill a gaping hole in our knowledge of terra incognita (viz. the eastern Himalaya). Traditional structural mapping techniques are being combined with geodetic (satellite global positioning system [GPS]) data and age dating of river terraces formed during mountain building and erosion.The research is determining: (1) the amount of shortening across the eastern Himalaya, (2) the variation of convergence along the Himalayan arc, and (3) whether the rates of convergence are the same for geologic time scales as compared to current [GPS] rates. This study, together with earlier work in southern Tibet under Project INDEPTH, is providing the first complete structural transect across the Himalayas from India to Tibet, and will form the basis for developing comprehensive models of mountain belt evolution in active belts. The study is also revealing whether or not zones in the mountain belt are building anomalous strain that could lead to great earthquakes in this region that has one of the highest seismic hazard risks along the Himalayan arc. The study is promoting collaboration of researchers from two countries, melding different field techniques, and helping in the training of future geologists.

喜马拉雅山脉带是印度和欧亚构造板块之间的大陆-大陆碰撞的结果，该碰撞始于50-55百万年前，并一直持续到今天。总的~650公里的板块会聚的一个重要部分是在喜马拉雅山脉形成缩短构造。由于喜马拉雅山的弧形形状，缩短度沿其长度沿着变化。缩短的数量以前只记录在喜马拉雅山脉西部（克什米尔，库马翁，尼泊尔）。该项目正在沿着Tista流域（东经约89度）进行一对沿着的详细断面，以填补我们对未知土地（即喜马拉雅山东部）的知识中的一个空白。传统的结构测绘技术正在与大地测量技术相结合，（卫星全球定位系统[GPS]）数据和年龄测定在造山和侵蚀过程中形成的河流阶地。研究确定：（1）东喜马拉雅的缩短量，（2）会聚度沿着喜马拉雅弧的变化，以及（3）与当前[GPS]速率相比，地质时间尺度的收敛速率是否相同。这项研究，加上早期在西藏南部的INDEPTH项目下的工作，提供了从印度到西藏的第一个完整的喜马拉雅山脉的结构样带，并将形成在活动带中开发山带演化的综合模型的基础。该研究还揭示了山区地带是否正在形成异常应变，可能导致该地区发生大地震，该地区是喜马拉雅弧沿着地震危险最高的地区之一。这项研究促进了两国研究人员的合作，融合了不同的野外技术，并有助于培养未来的地质学家。