Oil & Gas Geology ›› 2019, Vol. 40 ›› Issue (4): 763-777.doi: 10.11743/ogg20190407

Previous Articles     Next Articles

Characteristics of major unconformities and paleo-geomorphology during the Mesozoic key transformation stages in Kuqa-Tabei area

Wu Gaokui1, Lin Changsong1,2, Liu Yongfu3, Liu Jingyan1, Yang Xianzhang3, Li Hao2   

  1. 1. School of Energy Resources, China University of Geosciences(Beijing), Beijing 100083, China;
    2. School of Ocean Science, China University of Geosciences(Beijing), Beijing 100083, China;
    3. Research Institute of Exploration and Development of Tarim Oilfield Branch Company Ltd., Korla, Xinjiang 841000, China
  • Received:2018-10-01 Revised:2019-01-11 Online:2019-08-28 Published:2019-06-01

Abstract: Research on major unconformities and large-scale palaeo-uplifts developed during the key transformation stages in sedimentary basins is key to revealing the basin dynamics evolution and hydrocarbon accumulation.Based on the integrated analysis of seismic, logging and outcrop data, we demonstrated the characteristics of the Mesozoic major unconformities and palaeo-geomorphology, as well as how they are influenced by the dynamics evolution of Kuqa-Tabei basins through tracking unconformity truncation and onlap points, etc.Results show that the study area in the Mesozoic undergone four key transformation stages, namely the Late Permian, Late Triassic, Late Jurassic, Late Cretaceous stages; in turn four regional angular unconformities, namely TT, TJ, TK and TE, which have brought significant impact on the basinal tectonic palaeo-geomorphology.The transformation occurring at the Late Permian was mainly characterized by the development of large-scale palaeo-uplift belts in the central and western parts of the study area, and the unconformity TT was mainly distributed around the palaeo-uplifts with the maximum denudation thickness of 1 200 m.The tectonic movement of the Late Triassic resulted in a significant reactivation of the palaeo-uplift belts in the study area, and the unconformity TJ produced is of wide range with the maximum denudation amounting to 400 m.The tectonic movement taking place in the Late Jurassic resulted in another stage of uplifting and denudation in the central and western of the study area, and consequently the unconformity TK was developed with the maximum denudation of 500 m.The transformation of the Late Cretaceous is mainly characterized by the development of the Wensu palaeo-uplift at the western margin of the study area, and its associated unconformity TE is of limited distribution with the maximum denudation amounting to 300 m.Three geomorphologic units are recognized in the Mesozoic palaeo-highs, that is the uplift high, slope and depression areas.Around the slope area formed unconformity triangle zones, which are favorable for the development of litho-stratigraphic traps.In addition, it's believed that the four collisional orogeneses occurring around the basins had driven the formation of four transformation stages in the Mesozoic.

Key words: collisional orogenesis, transformation, unconformity, palaeo-geomorphology, maximum denudation thickness, Mesozoic, Kuqa-Tabei area

CLC Number: