Bright Spots, Structure, and Magmatism in Southern Tibet from INDEPTH Seismic Reflection Profiling
INDEPTH seismic reflection profiling shows that the decollement beneath which Indian lithosphere underthrusts the Himalaya extends at least 225 kilometers north of the Himalayan deformation front to a depth of approximately 50 kilometers. Prominent reflections appear at depths of 15 to 18 kilometers near where the decollement reflector apparently terminates. These reflections extend north of the Zangbo suture to the Damxung graben of the Tibet Plateau. Some of these reflections have locally anomalous amplitudes (bright spots) and coincident negative polarities implying that they are produced by fluids in the crust. The presence of geothermal activity and high heat flow in the regions of these reflections and the tectonic setting suggest that the bright spots mark granitic magmas derived by partial melting of the tectonically thickened crust.
Brown
LD
L. D. Brown, M. Hauck, D. Alsdorf, A. Ross, M. Clark, Institute for the Study of the Continents, Cornell University, Ithaca, NY 14853, USA. Wenjin Zhao and Xianwen Liu, Chinese Academy of Geological Sciences, Beijing 100037, China. K. D. Nelson and M. Cogan, Department of Earth Sciences, Syracuse University, Syracuse, NY 13244, USA. Jinkai Che, Bejing Computing Center, Ministry of Geology and Mineral Resources, Beijing, 100083, China.
Zhao
W
Nelson
KD
Hauck
M
Alsdorf
D
Ross
A
Cogan
M
Clark
M
Liu
X
Che
J