ORGANIC GEOCHEMISTRY AND DEPOSITIONAL ARCHITECTURE OF JIMUSAER OIL SHALE, JUNGGAR BASIN, NW CHINA

The Jimusaer oil shale (JOS) of the Upper Permian Lucaogou Formation in the southeastern margin of the Junggar Basin, Northwest China has retained a close relationship with the Bogda orogeny. JOS samples were studied for organic geochemistry, and samples of other rocks collected from between the oil shale layers (sandstone, mudstone shale, dolostone, limestone) were investigated for mineral characteristics. The results showed JOS samples to have a high total organic carbon (TOC) content, 5.35-21.45%, and a high oil yield, 3.67-10.3%. Dolomite, clay minerals, quartz, tuffaceous matrix, tuff debris, calcite, ferruginous debris, siliceous debris and anorthose could be found in the samples of other rocks. The Jimusaer oil shale was characterized by fine grain size, dark color and horizontal bedding. Depositional architecture and symbiotic rocks indicated that JOS was mainly deposited in a semi-deep to deep water environment under reducing conditions. The oil shale developed in the highstand systems tract (HST) and was enriched in organic matter.