【摘要】 歧口凹陷是地壳拆离断层(NENNE向沧东断层)NWSE向伸展作用和NNE向深断裂带走滑作用叠加的产物。新生代演化分为3个时期:始新世,由于NWSE向区域伸展作用,凹陷是一个由沧东断层控制的断坡凹陷;渐新世,凹陷受NWSE向区域伸展和NNE向深断裂带右旋走滑的共同作用;晚第三纪到第四纪,区域伸展作用基本停止,走滑作用仍在继续,由走滑作用导致的SN向局部伸展作用显得更加突出。构造演化对凹陷油气形成和分布有控制作用,凹陷西部和南部是有利的油气勘探区。更多还原

【Abstract】 Qikou Sag was developed at the combined effect of the NW-SE striking extension related to a detachment fault(the NE-NNEstriking Cangdong fault) in the crust, and the slipping effect of a NNEstriking deep fracture zone. During the Cenozoic, the evolution of the sag might be divided into three stages: during the Eocene, because of regional extension effect of the NW-SEstriking, it was a ramp depression controlled by the Cangdong fault; during the Oligocene, it might have subjected to the combined effects of the NW-SEstriking regional extension and the dextral slipping of the NNEstriking deep fracture zone; during the Neocene and the Quaternary, though the regional extension had mainly stopped, the dextral slipping continued. Inside the slip zone, the local, SNstriking extension related to the dextral slipping became more and more apparent. Tectonic evolution had a major control on the formation and distribution of the petroleum in the sag and its western and southern parts are promising hydrocarbon exploration areas.更多还原