Study Of Strata Sequence And Sedimentary Environments Of The Proterozoic Strata-Baiynebo Group, In Tai Pusi, Inner Mongolia

Tai pusi is located in the southeast of the Inner Mongolier, and belongs toXilinhot.Seldom scholars have researched here, especially about the Proterozoic strata.This paper focus at the Proterozoic stata, combining theories and means ofsedimentology, sequence stratigraphy, petro-geochemistry, history of meta-morphism ,in order to analyze the patterns of petro-combination and strata overlaping, types ofmeta-morphism, history of metamorphism, types of original rocks and geochemicalcharacteristics. On the basis of the above reaserches, we recover the sedimentaryenvironments.According to lithological association, spatial-temporal alternations of petrofacies,strata contact relationship and regional comparision, the middle and upper Proterozoicstrata are revisioned as Baiynebo Group, and devided into two stratigraphic formation:Baiyinbogela Formation and Hujiertu Formation. The rock assocination of theBaiyinbogela Formation is mainly grey and light grey quartzite withmedium-thickness seam in the middle and lower part of the Formation, and in thetopper part grey and lark quartz-mica-schist. The rock assocination of the HujiertuFormation is mainly graphite-monzonitic-diaposide-pyroxenolite with siliceous seam,plagio-pyroxenolite, potassium pyroxenolite,calcite-pyroxenolite andpyroxenolite-marble in the middle and lower part of the Formation,and in the upperpart thin-seam plagio-pyroxenolite and plagio-pyroxenolite-leptynite. BaiyneboGroup endured regional metamorphism in greenschist facies first and thermal contactmetamorphism in amphibolite facies. According to field geological characteristics,sedimentary structures, micro-structure characteristics, and geochemical data, therocks in this area is recovered as follows: quartzite(sand stone), schist(mudstone),diaposide-pyroxenolite(dolomite), marble(dolomite), leptynite(dolomite-sandstone ofmudstone). The sedimentary environments are recovered as passive continentalmargin shallow sea with carbonate and clastic deposits .