GSA Annual Meeting in Indianapolis, Indiana, USA - 2018

Paper No. 208-6
Presentation Time: 2:55 PM

TEARING OF INDIAN MANTLE LITHOSPHERE FROM HIGH-RESOLUTION SEISMIC IMAGES AND ITS IMPLICATIONS FOR LITHOSPHERE COUPLING IN SOUTHERN TIBET


LI, Jiangtao, Department of Geology, University of Illinois at Urbana-Champaign, Champaign, IL 61820 and SONG, Xiaodong, Department of Geology, University of Illinois at Urbana-Champaign, Champaign, IL 61820; School of Geodesy and Geomatics, Wuhan University, Wuhan, 430079, China

What happened to the Indian mantle lithosphere (IML) during the Indian–Eurasian collision and what role it has played on the plateau growth are fundamental questions that remain unanswered. Here, we show clear images of the IML from high-resolution P and S tomography, which suggest that the subducted IML is torn into at least four pieces with different angles and northern limits, shallower and extending further in the west and east sides while steeper in the middle. Intermediate-depth earthquakes in the lower crust and mantle are located almost exclusively in the high-velocity (and presumably strong) part of the Indian lithosphere. The tearing of the IML provides a unified mechanism for Late Miocene and Quaternary rifting, current crustal deformation, and intermediate-depth earthquakes in the southern and central Tibetan Plateau and suggests that the deformations of the crust and the mantle lithosphere are strongly coupled.
Handouts
  • GSA_2018_Li_Song.pdf (2.7 MB)