Early Mesozoic overthrust Tectonics around the Tanlu Fault Zone, Eastern China: Implications for the North and South China Collision

Although the NNE-trending Tanlu fault zone is overwhelmingly taken as a sinistral strike-Slip fault in western literature, we report intense early Mesozoic overthrust tectonics around entire Tanlu. This contractional deformation around Tanlu caused the North China block and the South China block to be shortened by at least 148 km (or 74%) and 158 km (or 56%) normal to Tanlu respectively, indicating that strong North China-South China convergence occurred along Tanlu and North China does not penetrate into the sedimentary cover of the South China block. Restoration of deformation the North China block shows that prior to the collision, the Sulu belt could have been in alignment with the original Tanlu fault. Paleozoic lithofacies and paleogeographic evidence shows that there seem both the southeastern North China promontory and the eastern Yangtze promontory, the latter including whole South Korea. The mutual penetration between these two promontories led to the separation of the original Tanlu suture into present southern Tanlu and Sulu with profound deformation of eastern China including the area around Tanlu. The northern segment of the Tanlu fault zone could have been initiated when the eastern North China block to the east of the Tanlu fault was extruded northwards toward the subduction zone around the North China and Siberia blocks, due to the impact of the Yangtze eastern promontory. Simultaneously, the escape of this block could have created space in the Sulu for the transportation of the UHP rocks that could have been originally exhumed near the Dabie Shan.