安达断陷深部火山岩识别及其意义

安达断陷深部发育火山岩。火山岩的产状多为层状、似层状和丘状。在白垩系沙河子组至营城组沉积期间有3次大规模的火山活动,形成了爆发相、溢流相和次火山岩相火山岩。火山岩的形成与分布与深大断裂有关,深大断裂薄弱部位或交叉部位,往往是火山喷出的通道。火山岩相在地震剖面上有不同的反射特征,其最突出的就是具有强烈的振幅反射。断陷内部的火山岩与盆地的形成、区域构造和油气的聚集有密切关系。

Recognition and Significance of Volcanic Rocks in Deep Anda Fault Depression

There exist volcanic rocks developed in Anda fault depression with stratified,quasi-stratified and moundy occurrences.During deposition of Cretaceous Shahezi formation to Yingcheng formation,3large-scale volcanic activities were taken place,shap-ing volcanic rocks of explosion,overflow and sub-volcanic rock facies.These volcanic rocks were related in formation and distri-bution to deep rift in which the thin or crossing places tend to be the channels of volcanic explosion.Different reflecting charac-teristics(e.g.,evident amplitude reflecting feature)of these volcanic rock facies can be seen in the seismic profile.The basinal formation,regional structure and petroleum accumulation are closely related to the volcanic rocks within fault depression.