内蒙古科右前旗树木沟地区大石寨组变质岩地球化学特征及原岩恢复

Geochemical Characteristics and Original Rock Restoration of the Dashizhai Formation Metamorphic Rocks in Shumugou area,Horqin Youyi Front Banner,Inner Mongolia

兴蒙造山带的大兴安岭地区,前人对火山岩成因和地球动力学演化机制研究较多,而大兴安岭中南段科右前旗的一带有关变质岩的研究还相对薄弱。本文通过对树木沟地区大石寨组变质岩进行地球化学分析及年代学研究,认为大石寨组变质岩地质年代为早二叠世,岩性组合为浅变质的中酸性火山碎屑岩夹砂岩,变质相为低绿片岩相;原岩主要为中性、中酸性晶屑凝灰岩,同时有少量沉积岩泥岩、砂岩,且原岩含有较多的石英及碳酸盐成分。

In the Greater Xing'an Mountains region of the Xingmeng orogenic belt,previous studies have focused on the genesis and geodynamic evolution mechanism of volcanic rocks,while research on metamorphic rocks in the Horqin Youyi Front Banner area of the central southern section of the Greater Xing'an Mountains is relatively weak.This article conducts geochemical analysis and chronological research on the metamorphic rocks of the Dashizhai Formation in the Shushugou area.It is believed that the geologi‐cal age of the Dashizhai Formation metamorphic rocks is the Early Permian,and the lithological combination is shallow metamor‐phic medium acidic volcanic clastic rocks mixed with sandstone.The metamorphic facies is low green schist facies;the original rock is mainly neutral and moderately acidic crystalline tuff,with a small amount of sedimentary mudstone and sandstone,and the original rock contains a large amount of quartz and carbonate components.