The Relationship Between The Laws Of Coal Accumulation And Sedimentary Environment In Muli Coalfield Qinghai Province

This paper based on Muli Coalfield existing geological exploration data and previous studies, directed by coal geology, sedimentology, sequence stratigraphy, lithofacies palaeogeography theory, make use of drill core, outcrops and logging data to study the lithofacies paleogeography,sequence stratigraphy and coal accumulation law, summarized Muli Coalfield depositional environment, established a re-stratigraphic framework to analyze the regularities of coal accumulation sequence stratigraphic framework, and predict the vantage zone to form coal.Muli Coalfield located in Datong Basin upstream with depression restricted by Datong Mountain south of the northern margin and Tuolai Mountain hedge fracture group, the structural form of a narrow quadrilateral distribution of NWW-SEE trending syncline. The main coal-bearing strata of the Jurassic Muli group and Jiangcanggroup,Jiangcang group of lower coal-bearing strata, with a total of 10 layers of coal;The upper Muli group on coal segment, with a total of 10 layers of coal. Muli Coalfield in the continental sedimentary basin dominated background, braided river delta and other three kinds of sedimentary system, six kinds of sedimentary facies and a variety of deposit types. This study established the Muli coalfield coal-bearing strata sequence stratigraphic framework and sequence comparison program, summed up the continental shelf basin sequence stratigraphic control law for coal development, proposed lake transgression system domain accommodation space control coal effect. Draw a percentage of sandstone Muli Coalfield, shale and sand mud percentages than other single factor contour map, on the basis of the recovery phase of the coal-bearing strata of ancient geographical features based on sequence stratigraphy of rocks, summary the paleogeographic evolution and characteristics of coal-bearing strata, and proposed the Mulicoalfield coal accumulation mode. And predicted more than 20 a favorable coal district,provides the basis for the next step to look for coal.