Activity time constraints and tectonic significance of the Cuona Detachment, southern Tibet

The South Tibet Detachment System ( STDS) is a set of stretched dissociation systems developed along the Himalayan orogenic belt, and its formation process is closely related to the uplift history and evolution process of the Himalayan orogenic belt, which is an important object for studying the tectonic deformation in the process of Indo-Eurasian collision and orogeny. Cuona Detachment ( CD) is a ductile shear zone several kilometers wide in which a large number of different types of leucogranites develop, and on the basis of large-scale field mapping, two phases of leucogranites are identified in CD: early syn-tectonic leucogranites and late post -tectonic leucogranites. In this paper, zircon LA MC-ICP-MS U-Pb analysis tests were performed on three early leucogranites bodies and two late leucogranites bodies. Zircon U-Pb dating results showed that CD continued to be active at 20Ma until it stopped around 14. 8 similar to 16. 5Ma. At the same time, combined with the results of previous research, the evolution process of STDS in the Cuona region and its difference along the orogenic belt were further explored. Along the Himalayan orogenic belt, the activity time of STDS in different regions showed obvious differences, and this paper believes that the STDS cessation time mainly shows a trend of gradually becoming younger from the western tectonic junction to the east ( such as the Cuona area).