Earth Science Frontiers ›› 2023, Vol. 30 ›› Issue (4): 245-259.DOI: 10.13745/j.esf.sf.2023.6.1

• Special Section on The India-Eurasia Collision and Its Long-Range Effect (Part 8) • Previous Articles     Next Articles

Sedimentary environment, provenance analysis and tectonic significance of the Upper-Cretaceous Abushan Formation in 114 Daoban, Anduo area, Qiangtang Basin

DU Lintao1(), BI Wenjun2,*(), LI Yalin3, ZHANG Jiawei4, ZHANG Shaowen1, YIN Xuwei1, WANG Chengxiu1   

  1. 1. Beijing Institute of Mineral Resources and Geology, Beijing 101500, China
    2. Department of Earth Sciences and Engineering, Taiyuan University of Technology, Taiyuan 030024, China
    3. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China
    4. State Key Laboratory of Earthquake Dynamics, Institute of Geology, China Earthquake Administration, Beijing 100029, China
  • Received:2023-05-22 Revised:2023-06-07 Online:2023-07-25 Published:2023-07-07

Abstract:

Late-Cretaceous continental strata of the Abushan Formation consist mainly of coarse clastic rocks and outcrop widely in the Qiangtang Basin, however, its sedimentary environment, source characteristics and tectonic setting remain unclear. In order to better understand the sedimentary evolution of the Qiangtang Basin and the early Tibetan Plateau uplift history after the Qiangtang-Lhasa collision we conducted detailed investigation into the depositional age, sedimentary environment, and source characteristics of the Abushan Formation in 114 Daoban, Anduo area. Angular unconformities were observed between the Abushan Formation and the underlying andesite and overlying Niubao Formation. Based on this observation, along with the eruption age of andesite and the depositional age of the Niubao Formation, we conclude that the Abushan Formation was deposited during the Late Cretaceous. Gravels of the Abushan Formation indicated a near-source deposition scenario as they mainly consisted of limestone and were transported over a short distance. Combined with geochemical data on sandstone detritus and heavy minerals, along with detrital zircon age spectra, we consider that the Abushan Formation was mainly sourced from Triassic-Jurassic strata in the southern Qiangtang and the central uplift zone. By comparing the stratigraphic characteristics between the Abushan Formation and its surrounding area, we suggest that the deposition of continental red clastic rock during the Late Cretaceous was related to large-scale thrusting in the Qiangtang Basin caused by continued plate convergence in the Qiangtang-Lhasa terranes.

Key words: Qiangtang Basin, Late Cretaceous, Abushan Formation, collision of the Qiangtang-Lhasa Terrane

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