Thrust Structure Developed in Pre-Tertiary Basement in South Area of Huanghua Basin

Thrust structure widely developed in pre Tertiary basement in south area of Huanghua basin. There are 6 structural styles in section which includes (1) snakehead and imbricate fan, (2) stack antiform, (3) duplex, (4) blind thrust in low angle or interbeds, (5) triangle zone and (6) high angle thrust domino. In the plane view, there are almost 5 parallel thrust zones striking in NE NNE. The names are given respectively by (1) Cangdong thrust zone, (2) Kongxi thrust zone, (3) Wumaying thrust zone (4) Xuhei thrust zone and Chenxi thrust zone from west to east. In the west part, the thrust structure dominates the styles of snakehead, imbricate fan and stack antiform. In the middle part, the thrust structure dominates the styles of duplex, blind thrust in low angle or interbeds and pop up and triangle zone. In the east part, the thrust structure dominates the styles of thrust domino. Most of the thrust faults are dip to SEE (southeast east) and the structural styles show the detachment of the thrust faults become deeper toward southeast. Possibly, all of the thrusts linked a large scale thrust system whose direction is from SE SEE to NW NWW. The strata involved the thrust system mainly include Paleaozoic group and Lower Middle Triassic but some leading thrusts have put in the Jurassic. We confer the thrust system was formed before Jurassic and after Triassic, and progressive thrust happened during Early Middle Jurassic. The thrust system superposed extensional and right lateral strike slip tectonics during Cenozoic. Some sections of Cangdong fault which was controlling the formation of Huanghua basin during Tertiary were thrust faults during pre Tertiary.