Crustal structure and tectonic study of North China Craton from a long deep seismic sounding profile

摘要

In this paper, we present the results of modeling refracted and reflected waves employing 2D ray tracing for a 1600-km long refraction/reflection profile that extends E-W across the entire North China Craton (NCC). The resulting P-wave velocity models reveal substantial structural variations among different geological units of the NCC. The Taihangshan Mountains are the geographical and geological demarcation lines of the NCC. In the eastern part of the NCC, Bohai Bay basin, the craton appears to be destructed as evidenced from the widespread of crust thinning (similar to 30 km), development of large sedimentary basins and weaken of crust-mantle boundary coupling. These features indicated that Cenozoic tectonic reactivation succeeded Mesozoic destruction in the eastern part of NCC. In the western part of NCC, the craton remains high crustal P wave velocity, stable, cold, and strongly crust-mantle boundary coupling crust. The Tanlu Faults and the Taihangshan Faults are the tectonic boundaries in the NCC and play important roles in the process of cratonic destruction. The structural feature of the east secondary tectonic differential settlement in the process of basin extension is that the most faults in Bohai Bay basin are the boundaries between the depression basin and uplift area. Comprehensive study found an apparent difference between the north and south part in eastern NCC destruction in that the large-scale Cenozoic stretching mainly occurred in the Bohai Bay basin and the weakly existed only in the local area and in Hehuai basin. We discussed the crust and upper mantle tectonic evolution of NCC under the action of the convergence of regional tectonic stress field in different geological periods since the Mesozoic era. The plate movement around NCC affects the lithospheric and crustal modification of the eastern North China, and controls the deep structural background of seismicity and metallogenesis. (C) 2014 Published by Elsevier B.V.