RII Track-4: Using Zircon (U-Th)/He Thermochronology to Explore a Link Between Mesozoic Tectonism and Nonmarine Sedimentation in the Eastern Tibetan Plateau

RII Track-4：利用锆石 (U-Th)/He 热年代学探索青藏高原东部中生代构造运动与海相沉积之间的联系

• 批准号: 1929117
• 负责人: William Jackson
• 金额: $ 14.65万
• 依托单位: University of South Alabama
• 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: 2019-12-15 至 2020-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1929117&HistoricalAwards=false
• 关键词: RII; Track; Using; Zircon; Th

The Tibetan Plateau, the largest and highest plateau on Earth, is a product of the India-Asia continent-continent collision. Because collision is ongoing, geologic processes can be observed and measured, making the Tibetan Plateau an ideal natural laboratory for tectonic investigations. While modern observations and measurements provide details pertaining to active tectonics of the plateau, studies show that ancient, inherited crustal features are a primary control for how the plateau is currently developing. In the eastern Tibetan Plateau, sedimentary and igneous rocks are exposed at the surface that provide a record of these ancient, pre-India-Asia tectonic events; however, these rocks remain largely unstudied. Therefore, the goal of this proposal is to investigate the age and geologic relationships of sedimentary and igneous rocks in the eastern Tibetan Plateau. This study will utilize field and laboratory methods to determine the timing and rates of pre-India-Asia geologic processes. By integrating field data with modern age dating techniques, the ability to quantify when and how these rocks were exhumed to the Earth’s surface will be possible. Advancing our knowledge in this region will allow us to better understand the Tibetan Plateau, as well as older mountain belts and large plateaus on Earth.Modern observations and measurements of Tibetan Plateau provide insights into active tectonic processes during plateau development. However, to fully incorporate these data a better understanding of inherited, Mesozoic tectonic fabrics must be established. In the eastern Tibetan Plateau, the northern Yidun terrane contains Mesozoic sedimentary and igneous rocks that record contractional deformation and exhumation; thereby, providing an opportunity to understand the spatial and temporal development of deformation in the Tibetan Plateau prior to the Cenozoic India-Asia collision. The goal of this proposal is to investigate a link between the exhumation of the Late Triassic Ganzi Pluton and development of two nonmarine sedimentary basins that are in stratigraphic and structural contact with the pluton. To approach this goal, the Principal Investigator (PI) proposes to use bedrock and detrital zircon (U-Th)/He thermochronology, working in collaboration with the Basin Analysis and Helium Thermochronology Laboratory (BAHTL) at the University of Connecticut, directed by Dr. Julie C. Fosdick. The proposed work is designed to address two main objectives, train the PI in zircon (U-Th)/He techniques and interpretations, and collect thermochronology data to explore a link between Mesozoic tectonism and nonmarine sedimentation. Results from this project will advance our understanding of Mesozoic tectonics in the eastern Tibetan Plateau, providing initial crustal input parameters for mechanical models. Advancing our knowledge of geologic processes that develop high-elevation ( 4 km) mountains and plateaus will help us better integrate large data sets that seek to understand global-scale natural processes.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.

青藏高原是地球上最大、最高的高原，是印度-亚洲大陆碰撞的产物。由于碰撞正在进行中，地质过程可以被观察和测量，使青藏高原成为构造调查的理想天然实验室。虽然现代观测和测量提供了有关高原活动构造的细节，但研究表明，古老的继承地壳特征是高原目前发展的主要控制因素。在青藏高原东部，沉积岩和火成岩暴露在地表，提供了这些古老的前印度-亚洲构造事件的记录;然而，这些岩石仍然在很大程度上未被研究。因此，本项目的目标是研究青藏高原东部沉积岩和火成岩的时代和地质关系。这项研究将利用现场和实验室的方法，以确定时间和速度的前印度-亚洲地质过程。通过将野外数据与现代测年技术相结合，将有可能量化这些岩石何时以及如何被挖掘到地球表面。通过对青藏高原的现代观测和测量，我们可以更好地了解青藏高原以及地球上古老的山地带和大型高原。青藏高原的现代观测和测量为我们了解高原发展过程中的活动构造过程提供了新的视角。然而，充分纳入这些数据，更好地了解继承，中生代构造组构必须建立。在青藏高原东部，北方义敦地区中生代沉积岩和火成岩记录了收缩变形和折返作用，从而为了解新生代印度-亚洲碰撞前青藏高原变形的时空发展提供了机会。该建议的目的是研究晚三叠世甘孜岩体的折返与两个与该岩体处于地层和构造接触的陆相沉积盆地的发育之间的联系。为了实现这一目标，首席研究员（PI）建议使用基岩和碎屑锆石（U-Th）/He热年代学，与康涅狄格大学的盆地分析和氦热年代学实验室（BAHTL）合作，由Julie C.福斯迪克拟议的工作旨在解决两个主要目标，培训的锆石（U-Th）/He技术和解释的PI，并收集热年代学数据，以探索中生代构造和非海洋沉积之间的联系。该项目的成果将促进我们对青藏高原东部中生代构造的理解，为力学模型提供初始地壳输入参数。提高我们对开发高海拔（4公里）山脉和高原的地质过程的了解，将帮助我们更好地整合寻求了解全球规模自然过程的大型数据集。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。