Eclogitization Of Indian Lower Crust During Its Northward Subduction Revealed By Receiver Function Depth Migration Images

The receiver functions calculated at the broadband seismic stations of TW-80 and Y2 array are used to reveal the main subduction features of the Indian plate beneath western Tibet. The H-kappa grid-searching results and CCP depth migration image show that the observed Moho structure at depth 67 similar to 80 km is laterally traceable from south to north on the west profiles in the study area, while there is another discontinuity interface at depth 40 similar to 55 km almost parallel to the Moho up to the station SQAT nearby the Shiquanhe thrust fault. This feature also can be seen on the CCP migration image on the east profile of the study area. Based on the evidence derived from this and previous petrology studies, we infer that the Indian lower crust front beneath western Tibet is located at Bangonghu-Nujiang suture, while it gradually reduces southward to the internal Lhasa block beneath central and east Tibet.