Geological and Geophysical Evidence for Deep Subduction of Continental Crust Beneath the Pamir

Geological and geophysical observations imply Cenozoic subduction of intact Eurasian continental lithosphere, approximately 300 km in downdip length and including relatively thin (20–25 km) continental crust, beneath the Pamir. An inclined seismic zone dips at about 45° south-southeastward to a depth of 150 to 200 km beneath the Pamir and projects to the surface near the northern margin of the Pamir. The downdip length of the seismic zone of about 300 km implies a comparable amount of subduction of lithosphere in late Cenozoic time. The seismicity and tectonically most active part of the Pamir and its surroundings follows the northern margin of the Pamir. Quaternary offsets on faults and repeated geodetic observations suggest that roughly half of India’s present 44-mm/a convergence with Eurasia is absorbed by localized crustal shortening and underthrusting at this zone.