Geological Structures And Evolution Characters Of Chifeng Basin

Through field geological survey and comprehensive analysis of coal and oil geological information,the basin's geological structures and characters were revealed.The study revealed that there were four sets of faults:NE?NNE?NNW-nearly SN?nearly EW direction faults and three sets of folds:NE?NW and nearly EW direction folds;The Chifeng basin was divided into three two structure units that Yuanbaoshan depression,Hongmiao low uplift and Sanyanjing depression;Chifeng basin was a dustpan-like depression of later Mesozoic Era basin.Wenquan-Danangou synsedimen-tary fault controlled basin formation and evolution;The structures of anterior basin formation was mainly for EW and early NE direction structure system;The structures of basin formation was mainly for NW direction structure system;Basin evolution experienced two stages of development that early chasmic stage and subject depression stage;In early Cretaceous Fuxin formation end of the period to Sunjiawan formation beginning,the NW-SE extrusing structure stress field made Chifeng rift basin died out;Since then the basin region underwent the structure rebuilding and the left going strike-slipping faults of NE direction and late NE direction structure system.On this basis,the coal controlling of geological structure was described.