ACCUMULATION STAGES AND EVOLUTION CHARACTERISTICS OF OIL SHALE AND COAL IN THE DUNHUA-MISHAN FAULT ZONE, NORTHEAST CHINA; pp. 203–215

Several coal- and oil shale-bearing basins are distributed in the Dunhua-Mishan Fault Zone in Northeast China, while there are certain differences in sedimentary association and occurrence characteristics between the deposited rocks. Based on the results of previous research on strati­graphic correlation, the depositional age of sediments in the Fushun Basin is the Paleogene-Eocene, in the Huadian Basin it is the Eocene-Oligocene, and in the Meihe Basin, the Eocene-Early Oligocene. In the Fushun Basin, huge thick coal seams were formed in the Guchengzi Forma­tion, thick low-quality oil shale layers were distributed in the lower part of the Jijuntun Formation and thick high-quality oil shale layers were developed in the Upper Jijuntun Formation. In the Meihe Formation of the Meihe Basin, coal seams were deposited in both the Lower Coal-bearing Member and the Upper Coal-bearing Member, while oil shale layers were formed in the Middle Mudstone Member. In the Huadian Basin, thin high-quality oil shale layers were deposited in the Oil Shale Member and thin coal seams were accumulated in the Carbonaceous Shale Member. Thick coal seams were mainly deposited in the swamp with abundant land plant supply during the initial tectonic subsidence stage of the Dunhua-Mishan Fault Zone in the warm and humid paleoclimate. Relatively high-quality oil shale layers were all formed in the deep lake during the maximum tectonic subsidence evolution stages of these three basins, and the organic matter sourced from algae. Oil shale in the Fushun and Meihe basins was deposited in the warm and humid paloeoclimate, while in the Huadian Basin the climate varied from wet to dry. Investigation showed the Dunhua-Mishan Fault Zone to have gone through two coal-forming stages and one oil shale-forming stage. Coal seams in the Fushun Basin and the lower part of the Meihe Basin accumulated in the Ypresian stage, while those in the Huadian Basin and the upper part of the Meihe Basin were deposited in the Bartonian-Priabonian stage. In contrast, oil shale layers in these three basins were all mineralized in the Lutetian stage.