The Study Of Sedimentary Characteristics And Accumulation Of Iqe Coalfield In Qinghai Province

This paper is based on the existing geological exploration data and the predecessors’study of the Iqe coalfield, and is guided by the theories of sedimentology and coal geology,regarding coal accumulation research as the main line, focusing on the study of the big ditchcoal group stratum and shimengou group. It combines geology with geophysical prospecting,outcropping with drilling control, detailed field observation with indoor macro analysis,integrity with key blocks, establishes stratigraphic sequence, and analyses the regularity ofsedimentary and tectonic control, then sum-arizes the distribution rules of coal resources inthe process of basin formation.Iqe coalfield, a long and narrow basin in north-west distribution, is located in the middleof northern Qaidam basin between the Lvliang Mountain in south and the upheaval ofKendaban Mountain in north. Its coal-bearing stratum are shimengou group (J2s) and large coalditch group (J2d) in Jurassic, including a total of7layers of coal or coal seam group (M1~M7), among which the M7and M5are the main minable seams. The research area ischaracterized by continental sedimentary, which mainly develops alluvial fan, braided river,braided river delta, meandering river delta and lake sedimentary fancies. According to thestudy of sequence stratigraphy, the complete development in middle and upper Jurassic isdiscovered in Iqe (developmental sequence6-10).According to analysis, the Iqe coalfield’scoal accumulating pattern contains alluvial fan, meandering river-meandering river delta,braided river-braided river delta,and lakes coal-forming environment, among which thesecond is the most advantageous. From the perspective of the coal forming environment, itcan be predicted that the west precise exploration in Gaxiu, the west of census area inYangshui River and the east of Yangshui River-Iqe (including the northern coalfield) have advantages of becoming coal area.