COLLISION BETWEEN THE NORTH AND SOUTH CHINA BLOCKS - A CRUSTAL-DETACHMENT MODEL FOR SUTURING IN THE REGION EAST OF THE TANLU FAULT

A crustal-detachment model, based on the interpretation of linear aero magnetic anomalies, surface geological observations, and deep seismic profiles, is proposed for the continent-continent collision between th e North and South China blocks east of the Tanlu fault. The model sugg ests that during the mid-Mesozoic collision between the two continenta l blocks, the upper crust of the South China block in the Subei-Yellow Sea region was detached from the lower crust and thrust over the Nort h China block for >400 km, whereas the lower part of the lithosphere w as subducted under the North China block along a subsurface suture run ning east from Nanjing. The sinistral offset of the Qinling suture by the Tanlu fault is only 110-120 km in the deep crust-much less than pr eviously suggested.