东喜马拉雅构造结剥蚀引起的变形：造山楔和热造山

项目名称： 东喜马拉雅构造结剥蚀引起的变形：造山楔和热造山

项目编号： No.41472175

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 钟大赉

作者单位： 中国科学院地质与地球物理研究所

项目金额： 120万元

中文摘要： 构造和地表过程相互作用和反馈影响着地壳变形。虽然众多复杂的数字模型可以模拟这一过程的诸多细节，但是能够明确证实的野外证据几乎没有。拟议项目选择具有独特优势的东喜马拉雅构造结作为检验剥蚀引起变形各种数字模型的野外实验室。在完善研究区热年代学编图、剥蚀历史和强度分区的基础上，通过野外地质调查，构造地质图的编制，热年代学研究，应变应力分析，重点选择热史演化和剥蚀强度（速率）差异边界、不同类型气候（冰川锯、雨影区）作用区，开展构造形态、变形序列、几何学、运动学、和年代学，探寻剥蚀引发地壳变形的作用方式。根据东喜马拉雅构造结野外地质事实，分别在其东侧识别出雨影区与造山楔模型的关联和冰川锯与热造山模型的内在联系，并试图检验和发展新的剥蚀引起地壳变形的模型。

中文关键词： 变形；剥蚀；东喜马拉雅构造结；造山楔；热造山

英文摘要： Interactions and feedbacks between tectonics and surface processes are affecting crustal deformation. Although sophisticated numerical models can simulate the details of such interactions, unambiguous field evidence remains scarce.The proposal selects the Eastern Himalaya Syntaxis as the field laboratory to investigate the deformational pattern induced by erosion. The links between precipitation, erosion rate and deformation have arisen to test the hypothesis that climate change can significantly influence the tectonic and structural evolution of mountain ranges.Based on the thermochronological mapping, the proposal will integrate the climate change, denudation rate and deformational pattern to test the hot orogeny model and orogenic wedge model. A rain shadow region can be recongnized in the eastern slope of EHS with high rainfall, high relif, steep river gradients and rapid young apatite fission-track ages. The typical profile，from Beiben, Hanmi to Doxiongla extending SE-NW direction cutting through the whole erosional wedge，will be studied using various structural geological methods to test the model of critical taper wedge.A glacial buzzsaw will be also found in EHS, which is above ELA and where is the potential for localized rapid erosion with the erosional rate more than 20mm/y. In this system, large volumes of hot, low-viscosity middle‐to‐lower crustal rock are drawn to mountain surface in the shape of dome or pop-up structure in the erosional core of EHS.In one mountain belt of EHS.These two different models will be test and get field verification. Coupled tectonic-erosion models will predict that the tectonic and structural evolution of a mountain belt is sensitive to spatial and temporal variations in erosional efficiency.

英文关键词： deformation;erosion;Eastern Himalayan Syntaxis;orogenic wedge;hot orogeny