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Geoscience ›› 2022, Vol. 36 ›› Issue (05): 1206-1217.DOI: 10.19657/j.geoscience.1000-8527.2022.043

• Hydrocarbon-bearing Basins • Previous Articles     Next Articles

Carboniferous Tectono-stratigraphic Division and Basin-forming Background in the Bogda Area, Eastern Tianshan

FAN Dan1,2(), LI Di1,2(), HE Dengfa1,2, HOU Shuoqin1,2, SUN Tiange1,2, YANG Hao1,2, ZHEN Yu1,2   

  1. 1. School of Energy Resources, China University of Geosciences, Beijing 100083, China
    2. Key Laboratory of Marine Reservoir Evolution and Hydrocarbon Accumulation Mechanism, Ministry of Education, Beijing 100083, China
  • Received:2022-03-01 Revised:2022-06-30 Online:2022-10-10 Published:2022-11-03
  • Contact: LI Di

Abstract:

The Bogda area experienced the evolution processes involving the Paleozoic subduction-accretion and Meso-Cenozoic multi-stage intracontinental deformation, but controversies remain regarding the Carboniferous tectonic attribute and evolutionary stages in the Bogda Mountain, which restricts further research on the late Paleozoic tectonic framework in North Xinjiang. Integrating the outcrop geology, borehole and seismic data from the Bogda Mountain and its adjacent basins, we carried on a comprehensive comparative study of the Carboniferous stratigraphic framework and magmatic characteristics in a basin-orogen scale by the basin analysis theory and method. Accordingly, we divided the Carboniferous tectonic-stratigraphic units in the Bogda area and analyzed the Carboniferous tectonic setting. Our results show that the unconformity between the Lower Carboniferous and pre-Carboniferous strata (C1/AnC) are present in the Junggar Basin and Tuha Basin adjacent to the Bogda Mountain, while the unconformities, including the Upper and Lower Carboniferous (C2/C1), and Permian and Upper Carboniferous (P/C2) ones, are commonly developed in the Bogda Mountain and its adjacent basins. Thus, the Carboniferous strata in the Bogda area are subdivided into two tectono-stratigraphic units, i.e., Lower Carboniferous and Upper Carboniferous, which reveals that the study area has undergone two major tectonic evolutionary stages. Combining the structural deformation evolution, basinal subsidence characteristics and tectonic setting, we suggested that the Carboniferous Bogda represents a back-arc basin in the subduction-related extension regime, which underwent two stages of rifting. The peripheral collisional events may have caused the later tectonic inversion for both rift basins during the late period.

Key words: Carboniferous, unconformity, tectono-stratigraphic sequence, back-arc rift basin, Bogda area, Tianshan Orogenic Belt

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