Sedimentary Environment on Upper Permian Linxi Group in Inner Mongolia

Key words: 
• Upper Permian /
• Linxi Group /
• continental facies /
• sedimentary environment

Abstract: In this paper, on the basis of previous studies, using geochemical method, the research was done on the Upper Permian sedimentary environment Linxi Group in northeast Inner Mongolia. The lithology in Linxi Group was black mudstone, silty mudstone, shale, gray muddy siltstone, and finegrained sandstone. By analyzing the constant element, trace element and rare earth elements, it was found that the entire sandmudstone sample had high SiO2, Al2O3, V, Zr, Ba, and low P2O5, Mn, CaO, Cd character. Through analyzing the discriminant index of the sedimentary environment, open freshwater was identified in Linxi Formation, mainly is the corresponding terrestrial facies, and belongs to marinecontinental alternating environment during the initial stage of deposition. Based on the sedimentary structure and lithologic association, Linxi Formation can be divided into lacustrine and delta facies, and the lacustrine can be subdivided into coastalshallow lacustrine and semideep and deep lakes, the delta facies includes delta front and prodelta.