松辽盆地营城组火山岩旋回和期次划分——以盆缘剖面和盆内钻井为例

Division of Volcanic Cycles and Stages of the Yingcheng Formation of the Songliao Basin——Take the Cross Sections at the Margin and the Boring Holes as Examples

松辽盆地营城组火山岩具有多期次、间歇性喷发特征。松辽盆地营城组火山岩研究采用旋回(对应于火山机构)-期次(对应于岩相组合)-岩相(对应于特定喷发方式及其产物)三级划分方案。期次是指一个喷发中心一次相对集中的(准连续)火山活动,在物质成分、喷发方式及喷发强度的规律性变化过程中,所形成的一套相序上具有成因联系的岩石组合。旋回由一个至若干个期次构成。在期次划分过程中,综合运用了地质方法与地球物理方法,充分利用岩性、岩相、测井和地震资料,依据相关地质界面,并与火山机构分析相互结合。据此将营城组建组次层型实测剖面划分为5个旋回,13个期次。

The volcanic rocks of the Yingeheng Formation in the Songliao Basin were formed by multiple and intermittent eruptions. Triple division was applied in the basin volcanic rocks researches： volcanic cycle, stage and facies. A volcanic stage was defined as volcanic rock assemblages formed by a concentrated volcanic activity at certain eruption center during its regular changes on materials, components, eruption behaviors and intensity. And a volcanic cycle includes one or several stages. Geological and geophysical methods were used to divide volcanic stages, including volcanic lithology and facies analysis from logging and seismic information. Special geological interfaces were identified. The measured section of the Yingcheng Formation has been divided into five volcanic cycles and thirteen stages.