Study on Jurassic sedimentary evolution and main control factors ofcoal accumulation in southwest margin of Tarim Basin

In order to further clarity the imbalance causes of coal measure distribution at the southwest edge of Tarim Basin and find the main control factors of the coal accumulation function,based on the application of the modern sedimentology,coalfield geology,tectonic geology and other theoretical method,with the analysis on the backfill and sedimentary characteristics of the Kangsu strike-slip pull-apart basin and the faulted basin in front of Kunlun Mountain,the lithological profiles of a single well,the sedimentary facies distribution diagrams of Shali Tashi Formation,Kangsu Formation,Yangye Formation as well as the thickness contour map of the Jurassic seam at the Southwest of Tarim Basin were drawn.The study results showed that the main control factors of the coal accumulation at the Southwest of the basin were the episodic tectonic movement,sedimentary environment and climate.The episodic tectonic movement determined two coal accumulation periods.The sedimentary environment determined a spatial distribution of the seam and the climate determined a migration of the coal-rich zone.Meanwhile,the evolution process of the Jurassic basin in the southwest area of Tarim Basin could be summarized as the initial settlement period,the first coal accumulation period,the coal accumulation migration period,the climate changing period,overlap period strong subsidence and six stages nappe period strong subsidence.