Normal faulting, basin development, and paleoelevation in south Tibet and the evolution of the Tibetan Plateau

藏南正断裂、盆地发育、古海拔与青藏高原演化

• 批准号: 410123364
• 负责人: Professor Dr. Ralf Hetzel
• 金额: --
• 依托单位: Abteilung Sedimentologie und Umweltgeologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2019
• 资助国家: 德国
• 起止时间: 2018-12-31 至 2023-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/410123364?language=en
• 关键词: Normal; faulting; basin; development; paleoelevation

The Tibetan-Himalayan orogen is the result of the ongoing plate convergence between India and Eurasia since the Early Cenozoic. At a late stage of this long-lasting history (i.e. since the mid- to late Miocene), the formation of several N-S trending rift systems dissecting the Tibetan Plateau highlights significant changes in the evolution of the orogen. The relation between the rifts in Tibet and the uplift of the plateau is the key to a better understanding of the geological evolution of the entire orogen. The joint Sino-German cooperation proposed here will focus on this major scientific problem by investigating the tectonic, sedimentological, and paleoelevation history of the Gyirong and Nima-Dingri Rifts, which extend over a distance of more than 300 km through the Lhasa terrane and into the Himalaya. The German group (this proposal) will apply low-temperature thermochronology (i.e. fission track and (U-Th)/He dating) on apatite and zircon along elevation profiles through granitic intrusions, which are exposed in the footwalls of the rift-bounding faults. Thermokinematic modelling of the respective data will allow us to quantify the onset of normal faulting and temporal variations in fault slip along strike of the Gyirong graben and the Nima-Dingri rift system. Our Chinese partners will use sedimentological and magnetostratigraphic analyses to reconstruct the evolution and the depositional environment of the fault-controlled Gyirong basin. On this basis, they will use stable isotope analysis of carbonate from paleosols, authigenic minerals, and fossils to decipher how the paleoelevation of the Gyirong basin has changed through time and how it is related to the activity of the basin-bounding faults. The complementary approaches and results of our two working groups will lead to an improved understanding of the causal relation between rift development, basin formation, and paleoelevation on the Tibetan Plateau and their timing with respect to past climate changes.

西藏-喜马拉雅造山带是印度和欧亚板块自早新生代以来持续汇聚的结果。在这一漫长历史的后期(即中新世中晚期以来)，解剖青藏高原的几个N-S向裂谷系的形成突显了造山带演化的重大变化。西藏裂谷与高原隆升的关系是更好地理解整个造山带地质演化的关键。中德提出的联合合作将围绕这一重大科学问题，研究吉隆裂谷和尼玛-定日裂谷的构造、沉积和古海拔历史。吉隆裂谷和尼玛-定日裂谷绵延300多公里，穿过拉萨地体进入喜马拉雅山脉。德国小组(这项提议)将通过花岗岩侵入体对沿高程剖面的磷灰石和锆石进行低温热年代学(即裂变径迹和(U-Th)/He测年)，这些侵入体暴露在裂谷边界断层的底部。相应数据的热运动学模拟将使我们能够量化正常断裂的开始和吉隆地块和尼玛-定日裂谷系统沿走向的断层滑动的时间变化。我们的中国合作伙伴将使用沉积学和磁性地层学分析来重建断控型吉隆盆地的演化和沉积环境。在此基础上，他们将利用古土壤、自生矿物和化石中碳酸盐的稳定同位素分析来破译吉隆盆地的古海拔随时间的变化及其与盆地边界断裂活动的关系。我们两个工作组的互补方法和成果将有助于更好地理解青藏高原裂谷发育、盆地形成和古海拔之间的因果关系，以及它们与过去气候变化的时间关系。