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

喜马拉雅山带是印度和欧亚大陆板块之间开始于5000-5500万年前并一直延续到今天的大陆-大陆碰撞的结果。在整个约650公里的板块汇聚中，有很大一部分是在喜马拉雅山脉形成的缩短构造。由于喜马拉雅山脉呈弧形，其长度上的缩短程度各不相同。缩短的数量以前只记录在喜马拉雅山脉西部(克什米尔、库曼、尼泊尔)。该项目正在沿着Tista排水系统(东经约89度)进行一对详细的横断面，以填补我们对不明陆地(即。东喜马拉雅山脉)。传统的构造制图技术正在与大地测量(卫星全球定位系统[GPS])数据和在造山和侵蚀过程中形成的河流阶地的年龄测定相结合。研究正在确定：(1)穿过喜马拉雅东部的缩短量，(2)沿喜马拉雅弧线的收敛变化，以及(3)与当前的[GPS]速率相比，地质时间尺度的收敛速度是否相同。这项研究与早先在藏南INDEPTH项目下的工作一起，正在提供从印度到西藏的第一个跨越喜马拉雅山脉的完整构造样带，并将为开发活动带山地带演化的综合模型奠定基础。这项研究还揭示了山带中的地带是否正在形成异常应变，这可能会导致该地区发生大地震，该地区是喜马拉雅弧线地震风险最高的地区之一。这项研究正在促进两国研究人员的合作，融合不同的现场技术，并帮助培训未来的地质学家。

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.