Multistage piecewise breakaway of subducted Indian continental lithosphere and its tectonic implications
Abstract
The evolution of Tibetan plateau has been taken as an excellent proxy to understand the continental collision and mountain building process. However, due to its harsh natural environment, the geophysical investigations including seismological observations have been limited until recent years. With several decades of efforts, the knowledge of the Tibetan crust and upper mantle structures has been significant improved but there are still controversial understandings for several basic aspects of the tectonic evolution. In this study, we combined the available seismic waveform data and carried out a finite-frequency tomography to enlarge the detection aperture and improve the resolution in both lateral and depth dimensions. The tomographic results show multiple high velocity anomalies in the mantle transition zone of Tibet, which are suggested to be detached Indian continental lithospheric segments. We have also conducted numerical simulations to examine the consequence for several detached blocks. The preliminary results show the interaction of the mantle flows induced by the detached blocks facilitate the development of surficial rifts in southern Tibet. We propose the subducted Indian continental lithosphere might have detached piecewise in sequence, which stimulate the east-west extension and potassic-ultrapotassic volcanism since Miocene.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMT025.0002L
- Keywords:
-
- 1031 Subduction zone processes;
- GEOCHEMISTRY;
- 7218 Lithosphere;
- SEISMOLOGY;
- 8104 Continental margins: convergent;
- TECTONOPHYSICS;
- 8120 Dynamics of lithosphere and mantle: general;
- TECTONOPHYSICS