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Journal of University of Chinese Academy of Sciences ›› 2023, Vol. 40 ›› Issue (5): 614-636.DOI: 10.7523/j.ucas.2021.0084

• Research Articles • Previous Articles     Next Articles

Tectonic evolution and mineralization of Carlin-type gold deposits in Youjiang basin

FENG Hongye1, JU Yiwen1, ZHU Hongjian1,2, YU Kun1,3, QIAO Peng1, JU Liting1, XIAO Lei1   

  1. 1. CAS Key Laboratory of Computational Geodynamics, College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China;
    2. School of Vehicle and Energy, Yanshan University, Qinhuangdao 066000, Hebei, China;
    3. School of Mines, China University of Mining and Technology, Xuzhou 221116, Jiangsu, China
  • Received:2021-09-27 Revised:2021-12-28 Online:2023-09-15

Abstract: Youjiang basin (Nanpanjiang basin) experienced a complex tectonic evolution of Paleozoic prototype basin-superimposed basin, and finally, it appears as a residual basin. According to the tectonic setting, sedimentary series and magmatic rocks, the evolution of Youjiang basin after Caledonian movement can be divided into six stages:intracontinental extensional basin (early rift valley) evolution stage (D21-D12), oceanic extensional basin (rift ocean basin) evolution stage (D2-T1), ocean basin extinction and foreland flexure basin evolution stage (T21-T13), fold orogeny and post collisional extension stage (T13-J1), NW trending compression orogeny stage (J2-K21), and local extension stage (K31-E). There are a large number of Carlin-type gold deposits in the basin, and most ore bodies occur in thrust-fold belts. The Carlin-type gold deposit has multi-stage metallogenic characteristics, large-scale mineralization mainly began in the compressive background and continued to the post orogenic extension stage, and there are two concentrated metallogenic periods. The first stage was formed in the evolution stage of foreland flexure basin related to collision orogeny to post collisional extension (235-193 Ma, Carlin-type gold deposit in the central and southern part of the basin). The mineralization in this stage was controlled by metamorphic hydrothermal fluids or hydrothermal fluids relate to magmatic melting which induced by the superposition of collision orogeny of the Yangtze Block and the Indochina Block and the subduction of the Paleo-Pacific plate to the Eurasian continent. The second stage was formed in the stage of NW trending compression orogeny to local extension (148-103 Ma, Carlin-type gold deposit in the whole Youjiang basin). The mineralization in this stage was mainly affected by the magmatic hydrothermal activities during the superposition and transformation of the pre-existing structures by the NW trending compression orogeny. Magmatic or metamorphic hydrothermal activities under extensional background before the Early Triassic has the effect of initial enrichment, and it has the effect of superimposed and reformation post mineralization after the Early Cretaceous. The ore-forming fluid of Carlin-type gold deposit has the characteristics of mixed sources. It is mainly metamorphic hydrothermal solution in the central and southern part of the basin, and mostly mixed source hydrothermal solution in the central part of the basin. While, the ore-forming fluid is mainly magmatic hydrothermal solution in the northern part of Youjiang basin. Through comparative analysis, it is considered that the ages obtained by different dating methods can represent the metallogenic age to a certain extent. And the combined application of multiple methods should be used to limit the metallogenic age of Carlin-type gold deposits.

Key words: Youjiang basin, basin evolution, Carlin-type gold deposit, superimposed reformation, metallogenic epoch

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