Collision between the northern Tibet and Tarim Block as revealed by the gravity data

The ongoing collision and continuous compression between the Indian and Eurasian plates began 55 Ma ago[1-3];this process created the magnificent Tibetan Plateau,the highest-elevation landform on the Earth today.Studies have shown that a conti-nent-continent collision occurred not only south of the Tibetan Plateau but also north of the plateau[4].However,compared with the evident subduction mode in the south(where the Indian Plate clearly subducts northward under the Tibetan Plateau)[5,6],the mode of the continent-continent collision in the north is still con-troversial:whether the Indian Plate subducts northward under the Tarim Block or the Tarim Block subducts southward under the Tibetan Plateau,or the Tarim Block played only a blocking role[4,7-9].A key to solving this problem is to establish a 3D geometric model of lithosphere structure.Considering that the fault zone of the West Kunlun Mountains on the northwestern edge of the Tibe-tan Plateau(Fig.1a)is an ideal place for detecting and revealing the continent-continent collisional processse in the northwestern part of the Tibetan Plateau[10],we applied a recently developed multi-scale imaging method[11]and 3D visualization technology to pro-cess the gravity data(Fig.1 b)covering the West Kunlun Mountains and its adjacent regions,and a 3D gravity model was constructed to understand the deep dynamics,collision mode,and contact rela-tionship between the Tibetan Terrane and Tarim Block in north-western Tibet.