CHARACTERISTICS OF LITHOFACIES PALAEOGEOGRAPHY AND SEDIMENTARY FILLING RESPONSE OF TRIASSIC IN TARIM BASIN

Based on an integrated investigation on well logging, seismic data, the characteristics of lithofacies palaeogeography and sedimentary filling response of main interface of Triassic in Tarim basin was analyzed in detail, through which, the sedimentary model was established.

The results show that during the Triassic period, the research area develops mainly lacustrine and deltas deposits. The paleogeographic units of this period include deep lake, semi-deep lake, shore-shallow lake, shore plain, braided delta, as well as fan delta. The uplift area around basin getting eroded, which act as the source to the central depression area of the basin. Fan delta developed in the submountain region of northern Kuqa Depression and two sides of Yakela fault block. Braided river delta developed in the Manjiaer Depression and southern central Tarim Baisn. Shore-shallow lake, semi-deep lake and deep lake transitional developed to the central basin. Inheritance character of Triassic in Tarim basin has been observed. In late Triassic, the lake began to shrink toward the north because of the collision of Qiangtang block and Tarim plate in the southern margin of Tethys and the depositional center moved northwards.