TECTONIC EVOLUTION OF QIKOU DEPRESSION IN THE BOHAIWAN BASIN OF EAST CHINA

After finding out the characteristics of spatial tectonic distribution in Qikou Depression,the evolutionary ideas and analytical methods of current regional tectonics are used to divided the tectonic evolution of Qikou Depression into six major stages:(1)strikeshear stage,(2)NW extension stage,(3)NW compression stage,(4)near NS rapid extension stage,(5)the transitional stage of near NS extension and thermal subsidence,and(6)thermal subsidence stage.