Sedimentary facies of Triassic-Jurassic formation in Yuqi area,Tarim Basin

Based on detailed field outcrop profiles and the core drilling observation,combining with the rock color,sedimentary structures,profile structures,log facies and seismic response,the sedimentary facies of Triassic-Jurassic formation in Yuqi area of Tarim Basin was analyzed,which is wet fan delta-lacustrine sedimentary system.The time and space evolution analysis result shows that during Triassic to Jurassic,the climate is humid,and the main sources come from the southern margin of Shaya uplift.There are two set of complete depositional cycles in Triassic formation,which are wet fan delta and lake.And due to the tectonic uplift of Indosinian movement,the top of Triassic formation and the Upper-Middle Jurassic formation are absent.Wet fan delta plain is developed in the Lower Jurassic formation.The research results are useful to understand the depositional environment during the period of Triassic to Jurassic,and can provide basic geologic data for oil and gas exploration in this area.