摘要
上二叠统林西组灰绿色岩段中首次发现了喷发相火山熔岩,其岩石组合为安山岩-英安岩,为低Na2O、富FeO的钙碱性岩系,岩石化学和稀土元素特征明显不同于侵入于林西组的侏罗纪脉岩。该套火山岩可能形成于陆内俯冲的构造环境,是西伯利亚古板块与中朝古板块在泥盆纪完成拼贴之后反复"挤压-松驰-再挤压"过程的末期阶段。同时,该火山岩组合中Sn、Pb、Zn等成矿元素含量比岩石圈背景值高出1～3个数量级。
Eruptive volcanic lava, being the rock assemblage of andesite to dacite and talc-alkaline series with low Na_2O and high FeO contents, was first discovered in gray green lithologic segment of Linxi formation, Upper Permian. It is obviously different from Jurassic dykes intruding into the Linxi formation characterized by lithochemistry and REE. This set of volcanic rocks possibly occurred in such tectonic setting of intracontinental subduction that belongs to the last stage of multiple compression-relaxation-recompression processions after accomplishing amalgamation between Siberia paleo plate and Sino Korean paleo plate in Devonian Period. On the other hand, the contents of ore forming elements such as Sn, Pb, and Zn in this set of volcanic rocks is 1 to 3 geometric scale higher than the background value of lithosphere.
出处
《矿产与地质》
2005年第1期1-6,共6页
Mineral Resources and Geology
基金
本文由国家自然科学基金(DO304-40273021)
中科院知识创新项目(KZCX1-07)资助。
关键词
火山岩
上二叠统林西组
火山熔岩
岩石地球化学
大兴安岭
volcanic rocks, Linxi formation of Upper Permian, eruptive volcanic lava, lithologicgeochemistry, Daxing'an Moutains
