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Geoscience ›› 2023, Vol. 37 ›› Issue (06): 1467-1481.DOI: 10.19657/j.geoscience.1000-8527.2023.001

• Ore Deposits and Regional Metallogeny • Previous Articles     Next Articles

Geochronological and Geochemical Characteristics of the Tianchitang Granodiorite in Southwestern Fujian Province: Indications for the Regional Metallogeny

ZHOU Yan1,2(), FAN Feipeng1,2, KANG Congxuan1, ZHAO Xilin1, XIAO Fan1,2, XU Mincheng1,2, SHEN Mangting1,2, ZHU Yiping1,2   

  1. 1. Nanjing Center,China Geological Survey,Nanjing,Jiangsu 210016,China
    2. Research Centre for Pacific Rim Strategic Mineral Resources,Nanjing,Jiangsu 210016,China
  • Received:2022-02-24 Revised:2023-01-05 Online:2023-12-10 Published:2024-01-24

Abstract:

Granodiorite,emplaced at the transition of Early to Late Cretaceous,is the most important Cu-polymetallic metallogenic intrusion in southwestern Fujian province.The Tianchitang granodiorite,located in the transition zone between the Cretaceous Zijinshan volcanic basin and the Late Paleozoic SW Fujian depression,presents a Cu-Fe skarn affinity at the outer contact zone.LA-ICP-MS magmatic zircon U-Pb dating of the granodiorite has been conducted to understand the regional magmatic mineralization,yielding weighted average 206Pb /238U ages of (100.7±1.0) Ma and (99.6±0.7) Ma. The result indicate that the granodiorite was emplaced early Late Cretaceous.Petrogeochemistry shows the intrusion is metaluminous-peraluminous and high-K calc-alkaline.The rocks are enriched in LILEs(Rb,Th,Zr and Hf) and depleted in HFSEs(Nb,Ta,Sr,Ti and P) with a weak negative Eu anomaly.The comparison with ore-forming intrusions in the Zijinshan orefield indicates that all of these intrusions were simultaneously formed in an extensional tectonic setting,and were the products of mixing of the granitul magma by partial melting of crustal material and mantle-derived mafic magma modified/influenced by subduction components. The ca.100 Ma granodiorite could resultsin different forms of mineralization in various locations.Therefore,it is a critical factor for the mineralization and prospecting of Cu-polymetallic deposits in southwestern Fujian province.

Key words: granodiorite, geochronology, geochemistry, mineralization, southwestern Fujian

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