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Geoscience ›› 2021, Vol. 35 ›› Issue (05): 1178-1193.DOI: 10.19657/j.geoscience.1000-8527.2020.096

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Detrital Zircon U-Pb Dating and Provenance Analysis for the Triassic Sandstone in Qilianshan Orogen, NE Margin of Tibetan Plateau

WU Long1(), LIU Changfeng2(), LIU Wencan3, ZHANG Hongyuan3   

  1. 1. Hubei Geological Survey, Wuhan, Hubei 430034,China
    2. School of Ocean Sciences, China University of Geosciences, Beijing 100083,China
    3. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
  • Received:2020-06-30 Revised:2021-08-30 Online:2021-10-10 Published:2021-11-04
  • Contact: LIU Changfeng

Abstract:

Triassic detrital sediments occurring in the northern margin of the Tibetan Plateau, which has been well studied in the Songpan-Ganzi terrane, yet the Triassic basin in the Qilianshan remain poorly understood. In this contribution, we integrated stratigraphy, sedimentology, zircon U-Pb dating on the Triassic sandstones in the Qilianshan to decipher their complex regional tectonic evolution. The results show that the ages of detrital zircons concentrate at four populations in 250-290 Ma,360-460 Ma,1,600-2,000 Ma,and 2,200-2,600 Ma. By comparing with the zircon age spectra in the North China Craton, South China Craton, and the Qinling-Qilian-Kunlun Central Orogenic belt, we suggest that the 1,600-2,000 Ma and 2,200-2,600 Ma zircon age populations were probably sourced from North China Craton, whereas a zircon age population of 360-460 Ma was derived from the North Qilian Orogenic Belt. The 250-290 Ma zircon population may have sourced from the volcanic arc of Eastern Kunlun Orogen in the south. The rare 600-1,000 Ma zircons were probably sourced from the Yangtze Block, since the Triassic North China-Yangtze collision along the Qinling Orogen may have acted as a barrier for the sediments from the Yangtze Block.

Key words: Qilianshan, Triassic sandstone, detrital zircon U-Pb dating, provenance analysis

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