摘要
对二连盆地北部地区中、新生代典型火山岩地球化学研究表明 ,该区中、新生代强烈的岩浆活动以酸性、中性火山岩为主。火山岩富集稀土元素 ,形成于大陆板块环境。侏罗纪为钾质碱性系列 ,古近纪为钙碱性系列 ,而且前者岩浆源较浅 ,岩浆分异作用差。自侏罗纪以来 ,该区地幔软流圈上涌 ,地壳拉张 ,控制中、新生代断陷盆地的形成与火山活动。持续的火山活动使该区地温梯度异常高 ,为次级断陷盆地内良好的烃源岩生烃过程创造了有利条件。
The study of the geochemistry for typical Meso Cenozoic volcanic rocks from northern Erlian basin shows that the main magmas are acidic to neutral. The relatively higher LREEs concentrations suggest that the volcanic rocks must be from surrounding continent block. The Jurassic volcanic rocks are belong to K alkaline and came from shallow crust with weak repartition of magma. However, Tertiary volcanic rocks are calc alkaline series. The upwelling of asthenosphere and extension of overlying lithosphere in Jurassic controlled the fault basins and volcanic actions in this area, which had high extension degree in Jurassic. The abnormal geothermal gradient due to the strong volcanic activities offered the favorable conditions for the hydrocarbon generation in the Erlian basin.
出处
《煤田地质与勘探》
CAS
CSCD
北大核心
2004年第2期26-30,共5页
Coal Geology & Exploration
关键词
火山岩
微量元素
构造背景
烃源岩
二连盆地
volcanic rock
trace element
tectonic background
hydrocarbon source rock
Erlian basin
