The Discussion Of Formation Mechanism And Prospecting Target In Archaeozoic Granite Greenstone Belt In The West Of Wuchuan County, Inner Mongolia

The study area is in the North China Craton tectonic zone. It is the major feature that developmental structure, frequent magmatic activity, Archean granitic metamorphic plutonic rock which occupy a prominent position, and the volcanic sedimentary-metamorphic iron ore and gold accompanying with the entire process.In study area the Archean greenstone belt include middle Archean Wulashan rock group gneisses formation (Ar2pg), marble formation (Ar2mb), and the new Archean Se’erteng rock group; the Archean metamorphic plutonic granite belt are composed of middle Archean Donghuofang metamorphic plutonic rock perilla frutescens felsic granulite and new Archean gneissic tonalite, gneissic quartz diorite.The formation of the study area granite greenstone belt has gone through several phases. In the first stage, continental crust cracking under extensional tectonic environment extend deposition oceanic basin; In second stage, due to increasing tensile force, intense volcanic activity occurred, forming a basic-intermediate basic volcanics formation. In the course of the eruption jet bring out a lot of iron and silica, which deposit in site to form ferrosilicon rocks, then it form volcanic sedimentary-metamorphic iron ore by metamorphism and recrystallization. In third stage, with the ocean basin sedimentary thickness increasing and sinking ocean basin tended to relatively stable from turmoil, while the force of the earth’s crust transforms from stretching into horizontal compression, tectonic movement end ocean basin sedimentary, strata begin to fold return, accompanied by a large number of TTG granitic rocks plutonic intrusion, It forms a complete granite-greenstone cycle. It form a complete granite-greenstone cycle, this cycle began by volcanic sedimentation to granitic plutonic body of intrusive and metamorphism, especially Neoarchaean granite-greenstone cycles are most obvious. These characteristics indicate the middle and new Archean granitic-greenstone belt formation process in study area.