Sequence Stratigraphy And Coal Accumulation Law Of Taiyuan Formation In Tashan Minefield,Datong

Guided by the theories and methods of sedimentology,petrology,sequence stratigraphy,energy geology,logging geology,organic geochemistry and other disciplines,this paper chooses Datangtashan mine of Tongmei as the research area.Based on the measured profiles,55 drilling wells,logging,core and geochemical analysis and testing data,the sequence stratigraphic framework,sedimentary environment and coal accumulation law of the Taiyuan Formation in the study area are studied.This is the case.Through sequence boundary identification and sequence stratigraphic correlation,the Taiyuan Formation is divided into four third-order sequences,and the sequence stratigraphic framework of the Taiyuan Formation in the study area is established.Three sedimentary facies,six sub-facies and 10microfacies types are identified in the Taiyuan Formation in the study area,and their characteristics are summarized.On the basis of the establishment of sequence stratigraphic framework,the distribution law of sedimentary facies of each sequence is established and systematically analyzed.The vertical,horizontal and horizontal distribution characteristics of the main coal seams in the sequence stratigraphic framework,and the coal accumulation model of 8~#and 3-5~#main coal seams are established.The 3-5~#coal seams and 8~#coal seams are mainly formed near the maximum flooding surface in the upper part of the transgressive(TST)system tract,and the top of the coal seam is the maximum flooding surface of the transgression in this period;the 8~#coal seams are mainly developed in the peat marsh microfacies of the lagoon-tidal flat sedimentary system;and the 3-5~#coal seams are widespread.Pan-developed shallow-water delta sedimentary system distributary Bay and peat swamp microfacies,and analysis of sea level changes,tectonic changes,paleoclimate,paleophytes and other conditions on the control of coal seam accumulation and preservation in the study area.