伊通盆地断裂体系特征及其演化历史

Fault System's Characteristics of Yitong Basin and Its Evolution

综合利用最新的地震、航磁、钻井等资料,对伊通盆地断裂体系进行了重新认识,并对断裂演化及其油气成藏的控制作用进行了综合分析。伊通盆地主要是受西北缘走滑断裂控制的新生代走滑-伸展盆地;断裂的性质、特征及演化极其复杂,按断裂特征及规模可划分为3个级别。一级断裂为西北缘和东南缘控盆边界断裂;二级断裂为早期张扭作用形成的呈雁列展布的马鞍山断裂,2号、3号、4号断裂和晚期压扭作用形成的西北缘逆冲断裂;三级断裂为盆地演化过程中形成的众多次级断裂。伊通盆地断裂演化特征与太平洋板块的俯冲作用、印度板块和欧亚大陆碰撞作用以及盆缘大黑山地垒和那丹哈达岭地体挤压位置与隆升强度密切相关,断裂演化经历了古近纪成盆期的右旋张扭作用阶段和新近纪反转期的右旋压扭及基底隆升作用阶段;新近纪反转期压扭作用形成的西北缘断褶带具有良好的油气勘探潜力。

According to the data of seismic, aeromagnetic, well drilling, etc, the authors restudy the characteristics of the fault system in Yitong basin, analyzes its evolution and the control effect on the hydrocarbon accumulation. Yitong basin is a strike-slip stretching basin which is controlled mostly by the strike-slip fault of the north-west boundary in Cenozoic. The features and evolution of the basin＇s faults are very complex, the faults can be classified as three distinction based on their characteristics and sizes. The first distinction faults include the north-west boundary fault and the south-east boundary fault; the second distinction faults include the stretching faults such as Maanshan fault, number 2 fault, number 3 fault, number 4 fault and the thrust fault along the north-west edge; the third distinction faults include the rest faults of the basin. The faults＇ evolution features in Yitong basin took place in the regional dynamic setting that back-arc spreading caused by westward subduction of the Pacific plate, and the collision from the Indian plate also played a partial role in the E- W compression in the East China. Besides this, the distribution and uplift strength of rigid plates of Daheishan and Nadanhadaling Mountain play a great role on the fault evolution. The fault evolution includes two stages： the early dextral strike-slip stretching stage and the dextral strike-slip compressing stage in basin＇s reverse period. The dextral strike-slip compressing forms the fault-folds belt by the north-west edge and it has great poten tial for hydrocarbon exploration.