徐家围子断陷白垩纪火山活动与断裂组合关系

本文从断裂组合、火山机构和岩浆通道等方面分析，提出徐家围子断陷基底断裂及与之匹配的次级断裂控制白垩纪火山活动，形成受基底断裂控制的三个 NNW 向展布的火山岩发育带。由于基底断裂特征不同，各火山岩带分别具有中心式、裂隙式和复合式三种不同的喷发特征。徐家围子断陷安达地区精细解剖表明，其基底断裂上部发育 NWW 向雁列式断裂，向下沟通基底断裂，为西部火山岩浆上侵通道，反映了历史时期内火山活动西强东弱的特征，西部火山规模大，以爆发相为主，东部为大面积溢流相。火山岩的分布受基底断裂及沟通其的次级断裂控制，同时对断裂痕迹起到一定的改造作用。

Relationship of Cretaceous volcanic activities and fracture combination in Xujiaweizi fault depression

The authors pointed out that Cretaceous volcanic activities were controlled by the basement faults and secondary faults in Xujiaweizi, and formed three NNW -trend volcanic rock belts controlled by basement faults, through the study on the relationship among fracture combination, volcanic mechanism and karst channels. Due to the different characteristics of the basement faults, the volcanic rock belts had three eruption characteristics ： center, fracture, and compound in type. The careful dissection of Xujiaweizi fault depression in Anda area showed that： the NWW- trend echelon fractures developed in upper basement fractures and communicated the basement faults downward, which were the volcanic magma invasion routes in western area. These phenomenon reflected the volcanic activity stronger in the west than in the east in the history period, i.e. the volcanic scale was larger in the west, charactered by burst facies, while showed effusive facies in the east. The distribution of volcanic rocks were controlled by basement faults and secondary faults, which also played a remolding part to fracture trace.