辽北汛河地区元古代海相火山岩——细碧岩地质特征

THE GEOLOGICAL CHARACTERISTICS OF PROTEROZOIC MARINE VOLCANIC ROCKS——SPILITE IN THE XUNHE AREA,NORTHFRN LIAONING

汛河地区元古代地层中,广泛分布的越性火山喷发岩,以往通称为“大甸子安山岩”,分布面积约2000km^2,对该火山岩的成因和时代长期存在争论。作者根据近年来一比五万区调资料,对该火山岩的区域分布、地质产状、岩石类型、矿物成分及结构构造、岩石化学等特征,进行了详细的论述。确认其时代应属元古代雾迷山期的海相火山岩——细碧岩,并建立二道沟亚组。

Basic volcanic extrusive rocks didtributed extensively in Proterozoic strata in the Xunhe area in northern Liaoning were previously called the“Dadianzi andesite”,covering an area of about 2000 sq km.The oreigin and age of the volcanic rocks have long been controversial.According to the data of 1:50000 regional surveys obtained in recent years,the paper deals with the regional distribution,geological occurrence,rock types,mineral composition,textures and structures and petrochemistry of the volcanic rocks.Finally they are confirmed to be marine volcanic rocks—spilite—of Wumishanian age(Proterozoic)and the Erdaogou Subformation has been established.