U–Pb dating,geochemistry, and Sr–Nd isotopic composition of a granodiorite porphyry from the Jiadanggen Cu–(Mo) deposit in the Eastern Kunlun metallogenic belt,Qinghai Province,China |
| |
| Institution: | 1. State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing 210023, China;2. Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia;3. National Research Center of Geoanalysis, Chinese Academy of Geological Sciences, Beijing 100037, China;1. State Key Laboratory of Geological Processes and Mineral Resources, Faculty of the Earth Sciences and Resources, China University of Geosciences, Beijing 100083, China;2. Department of Geology, University of Regina, S4S 0A2 Regina, Canada;3. State Agency of Geology and Mineral Resources, Bishkek, Kyrgyzstan;1. Department of Earth Sciences, Durham University, Durham DH1 3LE, UK;2. State Key Laboratory of Geological Processes and Mineral Resources, and School of Earth Science and Mineral Resources, China University of Geosciences, Beijing 100083, China;3. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China;1. State Key Laboratory of Geological Processes and Mineral Resources, China University of Geosciences, Beijing 100083, China;2. Key Laboratory of Orogen and Crust Evolution, Peking University, Beijing 100871, China;3. State Key Laboratory of Endogenic Deposits, Nanjing University, Nanjing 210023, China;4. Beijing Institute of Geology for Mineral Resources, Beijing 100012, China;5. Guangzhou College South China University of Technology, Guangzhou 510802, China;1. Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, Peking University, Beijing 100871, PR China;2. Department of Geosciences, University of Arizona, Tucson, AZ 85721, USA;3. Faculty of Geology and Geophysics, University of Bucharest, Bucharest, Romania;4. Development Research Center, China Geological Survey, Beijing 100037, PR China |
| |
| Abstract: | The Jiadanggen porphyry Cu–(Mo) deposit is newly discovered and located in the Eastern Kunlun metallogenic belt of Qinghai Province, China. Here, we present a detailed study of the petrogenesis, magma source, and tectonic setting of the mineralization causative granodiorite porphyry. The new data indicate that the granodiorite porphyry is characterized by high SiO2 (68.21–70.41 wt.%) and Al2O3, relatively high K2O, low Na2O, and low MgO and CaO concentrations, and is high-K calc-alkaline and peraluminous. The granodiorite porphyry has low Mg# (38–46) values that are indicative of no interaction between the magmas and the mantle. The samples that we have examined have low Nb/Ta (9.17–10.3) and Rb/Sr (0.28–0.39) ratios, which are indicative of crustal-derived magmas. Source region discrimination diagrams indicate that the magmas that formed the granodiorite porphyry were derived from melting of a mixed amphibolite source in the lower crust. The samples have ISr values of 0.70954–0.70979, εNd(t) values of − 8.3 to − 7.9, and t2DM ages ranging from 1644 to 1677 Ma. These indicate that the magmas that formed this intrusion were generated by melting of Mesoproterozoic lower crustal material. Higher K(Rb) contents of the samples indicate that the magma source is high potassium basaltic material in the lower crust, which could be derived from an enriched mantle source. LA-ICP-MS zircon U–Pb dating of the granodiorite porphyry yields a late Indosinian age (concordia age of 227 ± 1 Ma; MSWD = 0.31), which is close to the molybdenite Re–Os isochron age (227.2 ± 1.9 Ma), indicating further the close relationship between the granodiorite porphyry and the Cu–(Mo) mineralization. These samples are LREE and LILE (e.g., Rb, K, Ba, and Sr) enriched, and HFSE (e.g., Nb, Ta, P, and Ti) depleted, especially in P and Ti, similar to the characteristics of volcanic arc magmas. This intrusion most likely formed during the later stage of Indosinian deep subduction of oceanic slab. This was associated with underplating of mantle-derived magmas, which provided heat for crustal melting. Similar to the Jiadanggen granodiorite porphyry, Indosinian hypabyssal intermediate-felsic intrusive rocks, formed under subduction tectonism or a transitional regime from subduction to syn-collision, make up the most important targets for porphyry Cu(Mo) deposits in the Eastern Kunlun metallogenic belt. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
