Exploring the Early History of the South Tibetan Fault System in Bhutan

探索不丹藏南断层系的早期历史

• 批准号: 0838112
• 负责人: Kip Hodges
• 金额: $ 27.97万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-04-01 至 2013-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0838112&HistoricalAwards=false
• 关键词: Exploring; Early; History; South; Tibetan

This research focuses on the South Tibetan fault system, one of the most enigmatic tectonic features of the Himalaya, and one that stirs much controversy in the Tectonics community. The South Tibetan fault system appears to be unique in that its kinematics are those of a low-angle, normal fault system while all other Himalayan fault systems with comparable displacements (many 10s to 100s of kilometers) have the more predictable kinematics of thrust fault systems typically found in mountain belts. The very existence of a feature like the South Tibetan fault system is indicating something fundamental about how the Himalaya, and mountain ranges in general, evolve. The PI and his colleagues work to clarify this message through their research. Unfortunately, in many parts of the Himalaya, the early history of the South Tibetan fault system has been obscured by late-stage deformation. This is not the case in Bhutan, where the PI and others have identified erosional remnants of early faults of the system that have been relatively undisturbed by younger deformation. This proposal describes targeted studies of these remnants. A broad array of techniques will be used to probe the early history of the fault system using these rare exposures. They include geologic mapping and structural analysis; quantitative element-partitioning thermobarometry; 40Ar/39Ar and (U-Th)/He thermochronology; and laser-ablation (U-Th)/Pb geochronology. Because the Himalaya and Tibetan Plateau are still evolving, studies of this natural laboratory provide critical information regarding the role that mountainous regions play in earth system function. For example, we know that the physiography of the Tibetan Plateau defines the weather patterns of the Asian monsoon climate, and this climate is the enabling mechanism for agriculture that feeds roughly 60% of the people on Earth. By detailing the processes that led to the establishment of the modern-day Himalaya and Tibetan Plateau, studies such as the one proposed here inform more effective strategies for the co-evolution of human societies and mountain landscapes.

PI和他的同事们通过他们的研究来澄清这一信息。不丹的情况并非如此，在那里，PI和其他人已经确定了系统早期断层的侵蚀残余物，这些残余物相对来说没有受到年轻变形的干扰。该提案描述了对这些残留物的有针对性的研究。一系列广泛的技术将被用于利用这些罕见的暴露来探测断层系统的早期历史。它们包括地质制图和构造分析；定量元素分配热气压测定法；40Ar/39Ar和(U-Th)/He热年代学；激光消融(U-Th)/Pb年代学。