LITHOFACIES AND PALEOGEOGRAPHY OF THE LATE CRETACEOUS——PALEOGENE OF THE TARIM PLATFORM

During late Cretaceous the Tarim platform was divided roughly into three zones. They were the eastern Tarim depositional zone, the Kepin-Bachu erosion zone and the western Tarim depositional zone. This framework of the paleogeography of the Tarim platform was essentially kept on in Paleogene. The marine upper Cretaceous-lower Tertiary systems of the western Tarim depositional zone were foundamentally of supratidal and intertidal facies. These facies zones were not favourable for generating oil. The promising sections for oil generation were as follows: upper and medium Kukebai formation, Yigeziya formation, lower Qimgen formation, Karatar formation and lower Uragen formation. The organic matter in these formations is of sapropel type. They are regarded as poor source rocks according to various oil generation indicators.