The Character Of Cretaceous Sequence Stratigraphy And Depositional System In Northern Kashgar, Tarim Basin

This paper which based on the theories of continental sequence stratigraphy andsedimentology, examines the sedimentary system, sequence stratigraphy, lithofaciespaleogeography of Cretaceous Formation in northern Kashgar, Tarim Basin by usinggeologic, sesmic and logging methods. On the basis of previous research on this study,we do a lot of study on the cretaceous stratum division and contrast by petrologicalcharacteristics, well logging, paleontology, geochemical data to divide and correct theCretaceous stratum of the study area.We found that the Mesozoic Cretaceous of thestudy area bottom-up have the Kizilsu Group,Kukebai formation and Dongbaformation(including the Yigeziya formation, and Wuyitake formation).It’s covered bygypsum rock of the in Paleogene Artashi gypsum seam.Using methods of thehigh-resolution sequence stratigraphy, and combining seismic stratigraphy analysis, wedivided the Cretaceous Formation into two super long-term, four long-term and eightmedium-term sequences cycle, meanwhile, we establishs sequence stratigraphicframework of the Cretaceous Formation in study area and also deeply investigates thecharacteristics of all levels sequence by seismic comprehensive analysis method.According to the integrative analysis of regional tectonic, sedimentary background,the field of outcrop, core observation, and combined with various wells and seimic data,this paper divided the sedimentary system of Cretaceous at study area into threesedimentary facies group,eight sedimentary facies, twenty-five sedimentarymicrofacies. The three sedimentary facies group mainly including Marine sedimentarymodel and Continental sedimentary model. The Marine-Continente trantion formationof the study area mainly developed in the upper Kizilsu formation.Finally, by means of seismic attributes, this paper have finished thesequence-lithofacies and paleogeography maps within the isochronous sequencestraigraphic framework of study area, adopting long-term and super long-term sequence cycle as basic mapping unit. And we proved that the study area had beenaffected by sea water in the late of early Cretaceous.