关键词: 火山岩, 营城组, 徐中断裂, 徐东断裂带, 徐家围子断陷, 松辽盆地

Abstract: Yingcheng Formation volcanic rocks in the Xujiaweizi rift depression of the northern Songliao Basin are most favorable reservoirs for natural gases, of which the first section is composed of an intermediateacidic volcanic rock mainly distributed in the central and southern rift depression, while the third section belongs to an acidic volcanic rock chiefly deposited in the central and northern rift depression. The latest research results of threedimensional seismic exploration indicated that the two have different developmental characteristics, the volcanic eruption and distribution for the first section of the Yingcheng Formation were significantly controlled by the Xuzhong fault, volcanos erupted from north to south (i.e. from the central depression to the southern depression), while the volcanic eruption and distribution for the third section were subjected to the Xudong fault zone, volcanos then erupted from south to north (i.e. from the central depression to the northern depression). Analyses on the composite correlation between the thickness of volcanic rocks and faults as well as regional tectonics characteristics showed that the developmental characteristics of volcanic rocks in the Yingcheng Formation are consistent with the geological law that the extensional thinning of the Songliao Basin lithosphere caused by the Pacific Plate subduction downward to the East Asian continental margin, the characteristics that volcanic rocks of the Yingcheng Formation erupted from the central rift depression to both the north and the south are consistent with the characteristics of the tectonic stress field and evolution rule of the rift depression.

Key words: volcanic rock, Yingcheng Formation, Xuzhong fault, Xudong fault zone, Xujiaweizi rift depression, Songliao Basin