Stratigraphic sequence of the Jurassic Badaowan Formation and coal-forming characteristics of the Kamst coalfieldi

Abstract：Based on drilling, logging, field outcrop and fossil data obtained in the Kamst coalfield and using the basic theory and method of classic sequence stratigraphy, the authors divided the sequence stratigraphy of the Badaowan Formation in this coalfield, and identified two 3rd-order sequences of SQ1 and SQ2. According to the style of stratigraphic superposition and cycle of sedimentation, the authors further subdivided them into six system tracts. On the basis of the basic deposition maps and the analysis of sedimentary environment, the authors have revealed that the sedimentary evolution characteristics of the Badaowan Formation were mainly affected by the difference in land forms and palaeoclimate. It is found that the coal-formation of the purpose layers occurred during the period of lowstand and highstand systems tracts, but lacustrine transgression was not conducive to coal accumulation. Through a detailed study of sedimentary characteristics and coal accumulation of the Badaowan Formation in the Kamst coalfield, this paper provides basic data for further coal exploration.