Lithospheric structure of western Tibet – A brief review

Abstract Over the course of the last hundred years or so, there have been countless seismic experiments conducted under the aegis of different research programs, which have aimed to investigate the structure of the crust and uppermost mantle of the western Tibetan Plateau. However, there have been fewer detailed lithographic studies of the western sector of the Tibetan Plateau, and those that have been conducted have principally fallen under the research umbrella of the ANTILOPE (Array Network of Tibetan International Lithospheric Observation and Probe Experiments). In this paper, we summarize the important research findings that have been gathered using comprehensive geophysical profiles, and provide an overall view of the lithospheric structure of the western Tibetan Plateau that has resulted from the onset of tectonic collision and the continuous convergence of the Indian and Eurasian plates since ~65 Ma ago. In western Tibet, the subducted Indian lithospheric mantle is moving towards the northern edge of the Plateau, colliding with the Tarim Basin at 80°E. However, the Tarim Basin shows different nature of subductions in eastern, central and western regions itself. The maximum Moho depth (~93 km) beneath the Qiangtang Terrane marks the northern margin of the decoupled underthrusting Indian Plate’s lower crust and the lithospheric mantle. The broader, stronger terrain of the western Tibetan Plateau may indicate an eastward-broadening shape and a lower Cenozoic shortening, and the relatively larger width of the Lhasa-Qiangtang terranes may be a key factor controlling the geodynamic evolution of the Tibetan Plateau.