Scientific Drilling ICDP Publications

Teleseismic primary (P) to secondary (S) converted waves recorded on the INDEPTH III seismic array have been used to detect lithospheric-scale deformation structures of the central Tibetan Plateau from the central Lhasa terrane to the central Qiangtang terrane. A south-dipping crustal converter is seen from the upper crust near the 500-km-long metamorphic core complex exposures in the Qiangtang terrane to the lower crust near the Bangong-Nujiang suture. At deeper depths, a southeast-dipping mantle converter is seen extending from ~50 km north of the Bangong-Nujiang suture at the depth of the Moho, to a depth of ~180 km, ~100 km south of the Bangong-Nujiang suture. We found the observations to be most consistent with a model of lithospheric deformation involving (1) southward subduction of the Tibetan lithospheric mantle along the Bangong-Nujiang suture and (2) thickening of the central Tibetan crust through a thick-skinned, crustal accretionary thrust-wedge structure in response to the India´s collision with Asia.

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Shi, D.; Zhao, W.; Brown, L. D.; Nelson, D.; Zhao, X.; Kind, R.; Ni, J.; Xiong, J.; Mechie, J.; Guo, J.; Klemperer, S. L.; Hearn, T. M. (2004): Detection of southward intracontinental subduction of Tibetan lithosphere along the Bangong-Nujiang suture by P-to-S converted waves. Geology, 32, 3, 209-212.