Geochemical Classification and Significance of Jurassic CoalBearing Source Rocks in Taibei Depression, TurpanHami Basin

Key words: 
• TurpanHami Basin /
• coalbearing source rocks /
• biomarkers index /
• type of source rock

Abstract: The sedimentary environments and the original inputs of source rocks close related with the nature of the organic matter, in different layers and different regions of Taibei Depression, TurpanHami Basin, due to the differences of the depositional environments and the original inputs of Jurassic coalbearing source rocks, result in differences of the geochemical index. The analysis of geochemical indicators of source rocks showing that Pr/Ph and C29ααα20R relative content are important indicators of redox environment and the salinity of water. At the same time, we found that the main indicators of the type of source rocks are aromatic hydrocarbon and asphaltene contents in the group composition of soluble organic matter, the ratio of saturated hydrocarbon and aromatic hydrocarbon ,also the ratio of nonhydrocarbon and asphaltene. Pr/Ph, gammacerane index are secondary indicators of classification of source rocks. The Jurassic coalbearing source rocks can be classfied into three categories by the above index in Taibei Depression.