Collaborative Research: What Created the Southern Tibetan Plateau Drainage Divide? Integrated Tectonic and Geomorphic Investigation of the Gangdese Range and Yarlung River

合作研究：是什么造成了青藏高原南部的排水分水岭？

基本信息

批准号：
1917695
负责人：
Adam Forte
金额：
$ 26.36万
依托单位：
Louisiana State University
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-01 至 2024-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1917695&HistoricalAwards=false
关键词：
Collaborative Research What Created Southern

项目摘要

Collisional motions between tectonic plates deform the Earth's crust, forming mountain belts over millions of years. This process is most visible along the boundaries between tectonic plates, but also occurs further away from plate boundaries, where more subtle features reflect deeper-seated tectonic movements. This project focuses on the Gangdese Mountains in southern Tibet, which host some of the highest mountains of the Tibetan Plateau. These mountains are located 200 kilometers north of the high peaks of the Himalayas, but are actively rising due to deep-seated faulting related to collision between the Indian and Asian tectonic plates. This range forms the boundary between the low-relief, relatively flat interior of the Tibetan Plateau that retains all precipitation in lakes, and the higher-relief region to the south that is drained by the Yarlung-Siang-Brahmaputra river. By mapping the geologic structures, determining when and at what rate rocks were exposed at the surface, and comparing these data to simulations of erosion due to precipitation and river incision, the project investigators will determine the details of the deep-seated tectonic motions and how these motions affected the landscape of the Tibetan Plateau and one of the largest river systems in Asia. Broader impacts of this project will include the development of teaching modules based on this research, the preparation of three PhD students and one postdoctoral researcher to join the skilled scientific workforce, and outreach to the public through museum-hosted instructional modules and public research presentations. This research seeks to understand how and to what extent Miocene to Recent tectonics affected the landscape and river systems of the southern Tibetan Plateau. The project will test the hypothesis that a major crustal ramp or duplex beneath the Gangdese Mountains drove rock uplift along the southern boundary of the Plateau, in the interior of the Himalayan orogenic belt, since at least Miocene time. Research will focus on whether rock uplift outpaced erosion and established the drainage divide that currently separates the expansive internally-drained region from the Yarlung-Siang-Brahmaputra river system to the south. To address this hypothesis and other alternative hypotheses, the researchers will conduct an integrated study involving field-focused structural geology, thermochronology, landscape evolution modeling, and detrital cosmogenic radionuclide dating. The hypotheses provide a set of testable predictions for the geometry of rock exposures and the history of deformation, timing and rates of rock cooling, expected landscape evolution in response to various tectonic and/or climatic drivers, and millennial-scale erosion rates for catchment basins. If a tectonic driver for establishment of the southern drainage boundary is supported by the data, then tectonics is also implicated in the evolution of the Yarlung-Siang-Brahmaputra River system, one of the largest in the world. This research will advance our collective understanding of how mountain belts and plateaus form in response to tectonics, how mountain landscapes evolve and respond to variable tectonic influences, and how major river systems develop during million-year to millennial timescales.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

构造板之间的碰撞运动变形了地壳，形成了数百万年的山带。这个过程沿构造板之间的边界最为明显，但距板边界更远，其中更微妙的特征反映了更深层面的构造运动。该项目的重点是西藏南部的甘格山脉，该山脉拥有一些藏族高原的最高山脉。这些山脉位于喜马拉雅山高峰以北200公里处，但由于与印度和亚洲构造板之间的碰撞有关的深层断层而积极上升。该范围构成了藏族高原的低浮雕，相对平坦的内部之间的边界，该内部保留了湖泊中的所有降水量，而南部的较高浮雕区域则由Yarlung-Siang-Brahmaputra河水排干。通过映射地质结构，确定何时和以何时在表面暴露的速率岩石，并将这些数据与由于降水和河流切口引起的侵蚀的模拟进行比较，项目调查人员将确定深层构造运动的细节以及这些运动如何影响藏族高原和最大河流系统的景观。该项目的更广泛影响将包括基于这项研究的教学模块的开发，三名博士学位学生和一名博士后研究人员的准备，以加入熟练的科学劳动力，以及通过博物馆主持的教学模块和公共研究演讲向公众推广。这项研究试图了解中新世如何以及在何种程度上影响了藏族南部高原的景观和河流系统。该项目将检验以下假设：哥伦德山脉下方的主要地壳坡道或双链体沿高原的南部边界在喜马拉雅造山带的内部驱动岩石隆起，至少至少是中新世的时间。研究将集中于岩石提升是否超过侵蚀，并建立了目前将广阔的内部排水区域与南部的Yarlung-Siang-Brahmaputra河系统区分开的排水鸿沟。为了解决这一假设和其他替代假设，研究人员将进行一项综合研究，涉及以现场为中心的结构地质学，热力学，景观演化建模和碎屑宇宙性放射性核素约会。这些假设为岩石暴露的几何形状以及岩石冷却的变形，时机和速率，预期的景观演化的历史提供了一组可测试的预测，以响应各种构造和/或气候驱动器，以及千禧年规模的侵蚀率。如果数据支持建立南部排水边界的构造驱动器，则构造也与Yarlung-Siang-Brahmaputra河系统的演变有关，这是世界上最大的元素。这项研究将促进我们对构造构成学的山皮带和高原如何形成的集体理解，如何发展和响应可变的构造影响，以及在百万年内如何发展为千禧年的时间表。这奖反映了NSF的法定任务，并通过使用基金会的智力效果来评估支持NSF的法定任务，并以评估的评估值得评估。