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Quantifying Long-Term Variations in tectonic and Climate-Driven Exhumation: Northwest Himalaya, India

量化构造和气候驱动的挖掘的长期变化：印度喜马拉雅山西北部

基本信息

批准号：
19924800
负责人：
Privatdozent Dr. Rasmus C. Thiede
金额：
--
依托单位：
School of Geographical and Earth Sciences
依托单位国家：
德国
项目类别：
Research Grants
财政年份：
2006
资助国家：
德国
起止时间：
2005-12-31 至 2008-12-31
项目状态：
已结题

来源：
https://gepris.dfg.de/gepris/projekt/19924800?language=en
关键词：
Quantifying Long Term Variations tectonic

项目摘要

Interactions and coupling between tectonics and climate-driven erosion are a first order control on the long-term evolution of active orogens and concepts have been developed that explain the changeover from tectonically to erosionally controlled exhumation processes in the tectonic evolution of orogens. The degree to which climate-driven erosion controls the Pliocene/Quaternary development of the southern Himalayan front is a matter of debate. The Himalaya forms an orographic barrier with strong gradients. Thus quantifying weather or not precipitation, erosion, and deformation patterns are correlated over geologic time should provide important insights into evolution of the orogen. We propose an integration of multiple low-temperature thermochronometers and thermokinematic models to test two controversial hypotheses surrounding the interaction of climate, tectonics, and erosion across the Himalayan front: (1) We will test if exhumation of the southern Himalayan front switched from a tectonic to climate-controlled mechanism between ~10 Ma and present, and (2) if spatial correlations between present-day precipitation and erosion rates have been persistent over million year timescales. To test these hypotheses we will process thirty new 40Ar/39Ar muscovite, zircon (U-Th)/He (ZHe), and apatite fission track (AFT) cooling ages. The data sets will extend over a ~100-km-wide segment with strong precipitation gradients parallel to the Himalayan front. New thermochronometer data will constrain spatial and temporal variations in erosion and along strike variations in the timing and magnitude of deformation on several major structures. We will integrate the data with a 3D thermokinematic model to simulate the thermal, structural, and erosional evolution of the NW Himalayan front. Three end-member scenarios will be tested for different erosion and faulting histories.

构造和气候驱动的侵蚀之间的相互作用和耦合是对活动造山带长期演化的一级控制，并且已经发展了解释造山带构造演化中从构造控制到侵蚀控制的剥露过程的转换的概念。气候驱动的侵蚀在多大程度上控制了喜马拉雅山南部前缘的上新世/第四纪发展，这是一个有争议的问题。喜马拉雅山脉形成了一个梯度很大的地形屏障。因此，定量的天气或不降水，侵蚀和变形模式是相关的地质时间应提供重要的见解造山带的演变。我们提出了多个低温热时计和热动力学模型的集成，以测试围绕喜马拉雅山脉前缘气候，构造和侵蚀相互作用的两个有争议的假设：（1）我们将测试南喜马拉雅前缘的折返是否在~10 Ma和现在之间从构造机制转换为气候控制机制，以及（2）现代降水和侵蚀速率之间的空间相关性是否在百万年的时间尺度上持续存在。为了验证这些假设，我们将处理30个新的40 Ar/39 Ar白云母，锆石（U-Th）/He（ZHe）和磷灰石裂变径迹（AFT）冷却年龄。这些数据集将延伸到一个约100公里宽的部分，其中强降水梯度平行于喜马拉雅锋面。新的热时计数据将限制侵蚀的空间和时间变化以及几个主要结构在变形的时间和幅度上的沿着走向变化。我们将把这些数据与三维热动力学模型结合起来，模拟西北喜马拉雅前缘的热、构造和侵蚀演化。三个端元情景将测试不同的侵蚀和断层历史。