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

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，地质过程可以观察和测量，使青藏高原成为构造研究的理想天然实验室。虽然现代观测和测量提供了与高原活动构造有关的细节，但研究表明，古代继承的地壳特征是高原目前如何发展的主要控制因素。在青藏高原东部，暴露在地表的沉积岩和火成岩提供了这些古老的、前印度-亚洲构造事件的记录；然而，这些岩石在很大程度上仍未被研究。因此，本研究的目标是研究青藏高原东部沉积岩和火成岩的年龄和地质关系。本研究将利用实地和实验室方法来确定印度-亚洲前地质过程的时间和速率。通过将现场数据与现代测年技术相结合，量化这些岩石是何时以及如何被挖掘到地球表面的能力将成为可能。提高我们在这一地区的知识将使我们更好地了解青藏高原，以及地球上更古老的山带和大型高原。青藏高原的现代观测和测量为高原发育过程中的活动构造过程提供了新的认识。然而，为了充分整合这些数据，必须建立对继承的中生代构造的更好理解。在青藏高原东部，北益顿地体发育中生代沉积岩和火成岩，具有收缩变形和掘出的特征；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一个机会。本文的目的是探讨晚三叠世甘孜岩体的发掘与两个与该岩体有地层和构造接触的非海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，与康涅狄格大学盆地分析和氦热年代学实验室（BAHTL）合作，由Julie C. Fosdick博士指导。提出的工作旨在解决两个主要目标：在锆石(U-Th)/He技术和解释中训练PI，并收集热年代学数据，以探索中生代构造作用与非海相沉积之间的联系。研究结果将有助于进一步认识青藏高原东部中生代构造，为建立力学模型提供初始的地壳输入参数。提高我们对形成高海拔（4公里）山脉和高原的地质过程的认识，将有助于我们更好地整合旨在理解全球尺度自然过程的大型数据集。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.