摘要
通过1∶25万阿荣旗幅地质调查,在阿荣旗孤山镇—东亚东镇一带发现一套酸—中酸碱性火山岩石组合,时代为晚白垩世,将其新建岩石地层单位——孤山镇组。孤山镇组主要分布于大杨树盆地南部,由流纹岩、流纹质火山碎屑岩、粗面岩和英安岩组成,上覆地层为嫩江组,下伏地层为甘河组。岩石高碱(Na2O+K2O=7.83%～10.28%),属酸碱性系列。轻稀元素土富集,δEu=0.39～1.07;Nb、Ta基本无亏损,P、Ti强烈亏损,可能形成于陆内断陷盆地活动结束时期。
Through the 1：250000 geological survey of the Arun Qi Sheet, an acid and intermediate-acid-alkaline volcanic rock association has been found in the Gushanzhen-Dongyadongzhen area, Arun Qi. Its age is Late Cretaceous. This association is established as a new lithostratigraphic unit-Gushanzhen Formation. The Gushanzhen Formation is mainly distributed in the south of the Dayangshu basin and is composed of rhyolite and its pyroclastic equivalent, trachyte and dacite. It is overlain by the Nenjiang Formation and underlain by the Ganhe Formation. The rocks are highly alkaline （Na2O＋K2O=7.83-10.28%）, belonging to the acid-alkaline series. They are enriched in LREE, with δEu=0.39-1.07, and exhibit no Nb or Ta depletion, while P and Ti are strongly depleted. Volcanic rocks of this Formation probably formed in the terminal stage of intracontinental downfaulting.
出处
《地质通报》
CAS
CSCD
北大核心
2005年第9期862-866,共5页
Geological Bulletin of China
基金
中国地质调查局国土资源调查项目(200213000025)资助
关键词
孤山镇组
晚白垩世
酸-中酸碱性
火山岩
阿荣旗地区
内蒙古
Gushanzhen Formation
Late Cretaceous
acid and intermediate-acid-alkaline
volcanic rocks
Arun Qi area, Inner Mongolia
