古龙断陷营城组一段火山岩特征与火山喷发模式

Volcanic Characteristics and Eruption Models of Yingcheng Formation No. 1 Member in Gulong Fault-Depression of Songliao Basin

利用钻、测井及地震等资料和技术,对松辽盆地古龙断陷营城组一段火山岩特征及火山喷发模式进行研究。结果表明,研究区发现有火山熔岩、火山碎屑熔岩、火山碎屑岩和沉火山碎屑岩4类火山岩石类型,主要发育爆发相、喷溢相和火山沉积相3种火山岩相。平面上,爆发相火山岩主要发育在研究区北部,沿各级控陷断裂呈串珠状分布;喷溢相火山岩沿断裂向构造低部位运移,在研究区大部分地区都有分布;火山沉积相主要分布在断陷的构造低部位。根据研究结果建立了研究区火山岩沿各级控陷断裂喷发的裂隙-中心式喷发模式。

The volcanic characteristics and eruption models of Yingcheng Formation No.1 Member in Gulong Fauh-Depression of Songliao Basin are studied based on the data and technologies of drilling, logging and seismic conditions. It is shown that four kinds of volcanic rocks, the volcanic lava, the volcaniclastic lava, the volcaniclastic rock, and the sed volcanic pyroclastic rock, were found in the studied area, with the development of mainly three kinds of volcanic facies： the explosive facies, the effusive facies and the volcanogenic sedimentary facies. On the plane, the explosive volcanic facies are mainly distributed at the north of the studied area, with a string of beads along the faults of every level, which control the fault-depression; the effusive volcanic facies are migrated towards the downstructure location along the faults, distributed largely at the studied area; and the volcanogenic sedimentary facies are mainly distributed at the downstructure location of the studied area. In view of the above facts, a crack- central vent eruption model is proposed, which assumes volcanic eruption at the every level of faults which controls the fault-depression, and which would provide some guidance for the further exploration of volcanic activities in the studied area.