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Geoscience ›› 2019, Vol. 33 ›› Issue (04): 691-702.DOI: 10.19657/j.geoscience.1000-8527.2019.04.01

• Petrology,Mineralogy,Ore Deposits • Previous Articles     Next Articles

LA-ICP-MS U-Pb Geochronology of Detrital Zircons from the Longwuhe Formation in Taxiu Area, the Junction Area Between the Qinling and Kunlun Orogenic Belts

LU Zongyue1,2, YU Xinqi1(), LIU Mannian2, ZHANG Zhen2, WEI Liyong2, ZHAO Changcun2, ZHENG Xin2, KOU Shaolei2, XU An’min2, WANG Zhaofan1   

  1. 1. School of Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China
    2. Former No.5 Gold Geological Party, CAPF, Xi’an, Shaanxi 710100, China
  • Received:2018-10-11 Revised:2019-01-16 Online:2019-08-20 Published:2019-09-05
  • Contact: YU Xinqi

Abstract:

The junction area between the Qinling and Kunlun orogenic belts has received wide attention for its unique geological compositions and complex orogenic structures. The preliminary analysis has been performed previously on the provenance of sediments in this area but still remained controversy. This paper selects clastic rocks from the Longwuhe Formation and uses LA-ICP-MS U-Pb ages of detrital zircons to restrict their provenance characteristics. Our results show that the zircon U-Pb ages can be divided into four groups, i.e., 2 746-2 084 Ma, 1 094-775 Ma, 492-411 Ma and 372-237 Ma. Among them, the 372-237 Ma group accounts for 56.79% of the total. This largest proportion age group is relatively concentrated with a evident peak, representing a series of tectonic magma events caused by the subduction of the A’nyemaqen ocean. The comprehensive analysis reveals that the sources of clastic sediments in the Longwuhe Formation are complex and diverse, including the northern margin of the Qaidam Basin, the Qilian orogenic belt and the Eastern Kunlun orogenic belt. The Eastern Kunlun orogenic belt is the largest provenance area of the Longwuhe Formation and provides most sedimentary materials.

Key words: provenance, the Longwuhe Formation, detrital zircon, LA-ICP-MS zircon U-Pb age, the junction area between Qinling and Kunlun orogenic belts

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