Abstract: Songliao Basin underwent active rifting in the Late Jurassic Huoshiling to Early Cretaceous Yingcheng (J₃h-K₁ych),followed by a post-rift phase in the Early Cretaceous Denglouku-Nenjiang(K₁d-K₁n)and a reversion phase in the Late Cretaceous-Cenozoic (K₂-K_z).The Xujiaweizi fault-depression is a representative gas-bearing sub-basin in the lower part of Songliao Basin in the rifting phase.During the rifting phase,the two evolutive phases of Xujiaweizi fault-depression were found:the main faulting period in the Huoshiling-Shahezi (J₃h-K₁sh) along the NW-SE direction,and the asgging period in the Yingcheng (K₁ych).In the end of K₁sh,Xujiaweizi depression reversed.The resource (K₁sh) deposited in the NW extending sub-basin.This discussing is of great benefit to defining the Later Mesozoic stress-field in northeastern China and to finding the new gas-field in the lower part of Songliao Basin.

Key words: Songliao Basin, Late Jurassic-Early Cretaceous, fault-depression, structural evolution, hydrocarbon accumulation

摘要： 徐家围子断陷是松辽盆地深层一个具代表性的含气断陷.研究表明断陷演化分为火石岭—沙河子期(J₃hK₁sh)和营城期(K₁ych)两个阶段.J₃hK₁sh期为断陷主要发育阶段,断陷为NW向,受NW向基底断层伸展控制.K₁sh末期存在一次较强的挤压反转,断陷发生褶皱与断层逆冲反转.K₁ych期具坳陷性质,盆地转为NNE向.J₃hK₁sh期断陷发育受NWSW向左行扭动应力场影响,NW向断陷段具有走滑拉分特点.沙河子期是烃源岩主要沉积期.J₃hK₁sh期形成的横向转换构造、断层斜坡和反转期形成的反转背斜,最有利于深层气聚集成藏.

关键词: 松辽盆地, 晚侏罗世—早白垩世, 断陷, 构造演化, 油气聚集