The Geological Characteristics Of Wulashan Gr. In Middle Archean In Alashan Zuoqi, Inner Mongolia

The geological characteristics of the middle Archean Wulashan Gr. in Alashan Zuoqi,Inner Mongolia is the monographic study of the project “The1:50000regional geologicaland mineral survey of alshan Zuoqi bayanmaodao.etal five images of the Inner MongoliaAutonomous Region ". The study area is located in the Tukemu and Chagandeersi,Alashan Zuoqi of the western Inner Mongolia plateau,and its geotectonics location belongsto the combining site of the western part of northern margin of north china block andTianshan geosyncline fold systemwith complex tectonic background. People who studied insenior metamorphic collectively called them as Alashan group. After HuoFuChen dividedAla shan group in the area into the middle Archean Busige group, Chen Zhiyong dividedAla shan group into the middle Archean Wulashan rock group. This paper adopted in theplan, and divided the Wulashan group into four rock group, i.e. Migmatite andmigmatization gneiss petrofabric, Marble petrofabric, Amphibole plagiogneiss petrofabric,Biotite plagioclase gneiss petrofabric.This paper systematically studies the geological characteristics of the middle ArcheanWulashan group in the Alashan Zuoqi and Chagandeersi area in the west ofLangshan,Inner Mongolia through the field geological survey, stratigraphic section, chipstudy, analysis of main elements and trace elements.Through comprehensive analysis ofstratigraphic characteristics, metamorphic intrusive rock types, rock types, metamorphicfacies watchcase, metamorphic protolith, deformation and metamorphism, and the tectonicenvironment formed, we thought the tectonic environment of the middle archean Wulashangroup should belong to the mid-ocean ridge and island arc or active continental marginenvironment. We restored the senior metamorphic protolith of Wulashan rock groupthrough TiO2-F, c-n-f, K-A, Niggli’s tetrahedron iconic metamorphic protolithrestoration illustration. The main rocks of the metamorphic protolith is tuffaceoussandstone and lithic sandstone,and they formed a set of high amphibolite faciesmetamorphic rock combination which formed through three periods of deformation andmetamorphism.