The sedimentary studies of Mesozoic-Cenozoic in the southwestern Tarim Basin indicated that the Early Cretaceous inherited the sedimentary features of the Jurassic, mainly dominated by continental deposits.As the Tethys ocean expanded from the Late Cretaceous to Oligocene, sea water flooded several times to Kashi, Yecheng and Hetian from west to east, forming the West Tarim Bay.Marine facies sedimentation developed from the Upper Cretaceous to the Eocene Wulagen Formation in the southwestern Tarim influenced by large scale transgressions when global sea level rose.After that, continental sedimentation took the leading position from the Eocene to the Oligocene Bashibulake Formation due to global sea level decrease.Sea level changed frequently from the Cretaceous to the Paleogene in the southwestern Tarim, resulting in the preservation of carbonate, gypsum salt and mud rocks of littoral and neritic lagoon facies.There are two sets of reservoir and cap rock assemblages, the one is carbonate rocks in the Upper Cretaceous Yigeziya Formation and gypsum salt rocks in the Paleogene Aertashi Formation, the other is carbonate rocks in the Paleogene Kalataer Formation and dark mudstones in the uplying Wulagen Formation.These two assemblages are important for oil and gas exploration in the southwestern Tarim Basin.%通过对塔里木盆地西南部中新生代地层沉积研究表明,早白垩世继承了侏罗纪的沉积面貌,以陆相沉积占主导,从晚白垩世初到渐新世,受特提斯海洋壳扩张影响,海水多次自西向东侵漫到喀什、叶城及和田等地区,形成了西塔里木海湾.受同期全球海平面整体上升时期大规模海侵影响,塔西南上白垩统-始新统乌拉根组主要发育海相沉积,之后受同期全球海平面整体下降时期海退影响,始新统-渐新统巴什布拉克组为陆相沉积.塔西南晚白垩世-古近纪由于海平面的频繁变化,发育了滨海、浅海-潟湖相的碳酸盐岩、膏盐岩及泥岩沉积体系,形成了上白垩统依格孜牙组碳酸盐岩与上覆古近系阿尔塔什膏盐岩及古近系卡拉塔尔组碳酸盐岩与上覆乌拉根组深色泥岩2套重要的储盖组合,是塔西南地区油气勘探值得重视的重要领域.
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