The Shanmen deposit,located in the Siping area of Jilin Province,is one of large-scale silver deposits in Northeast(NE)China.Due to its high Ag grade,associated gold resources and special tectonic location,this deposit has important theoretical and ore-prospecting significance.To present new data on the ore genesis,mineralization time and tectonic settings,the relationship between silver mineralization and intrusions in this deposit has been studied and some analyses have been carried out,including LA-ICP-MS zircon U-Pb dating,whole-rock major and trace element analysis and Sr-Nd-Pb isotope analysis of the granitoids associated with silver mineralization.Studies on deposit geology indicate that the ore-hosting granodiorite and monzogranite have intimate genetic relationships with silver mineralization.LA-ICP-MS zircon U-Pb dating results of the both intrusions are 167.6±1.9 Ma and 167.0±1.5 Ma,respectively,implying that the two intrusions and associated silver mineralization in the Shanmen deposit formed during the Middle Jurassic.Major element analytical data suggest that the two intrusions are high-K calc-alkaline series I-type granites and belong to metaluminous and peraluminous rocks.Both intrusions have similar REE characteristics with regard to the relative enrichment of LREEs,depletion of HREEs,obvious fractionation of LREEs and HREEs(ΣLREE/ΣHREE=8.68-14.09,(La/Yb)N=12.51-21.96),moderately negative Eu anomalies as well as weakly negative Ce anomalies(δEu=0.56-0.71,δCe=0.93-1.09).Moreover,the samples are generally enriched in LILEs and depleted in HFSEs.The rock assemblages and geochemical characteristics of granitoids in the Shanmen deposit suggest that they formed in an active continental margin associated with the Paleo-Pacific plate subduction.The Sr-Nd-Pb isotope compositions show that both the granodiorite and monzogranite have low Sr initial ratios and high Sm/Nd initial ratios.The εNd(t)values and young Nd-model ages are-3.2 to-1.7 and 990 Ma to 1110 Ma,respectively.Considering the Sr-Nd isotope compositions,in conjunction with the relatively high 206Pb,207Pb and 208Pb,alongside the relatively low 204Pb,it can be concluded that the Middle Jurassic intermediate-acidic magma represented by the studied monzogranite and granodiorite in the Shanmen deposit,was derived from the partial melting of juvenile lower crust enriched in mantle-derived materials and affected by the mixing of ancient crustal materials during the ascension and intrusion processes.

REN Yunsheng;SUN Xinhao;CAO Peng;HAO Yujie;GAO Yu

Hebei Key Laboratory of Earthquake Dynamics,Institute of Disaster Prevention,Sanhe,Hebei 065201,China;College of Earth Sciences,Jilin University,Changchun 130061,China;Chengdu Center of China Geological Survey,Chengdu 610081,China;Key Laboratory of Mineral Resources Evaluation in Northeast Asia,Ministry of Natural Resources of China,Changchun 130026,China

地质学报（英文版）

[1]REN Yunsheng;SUN Xinhao;CAO Peng;HAO Yujie;GAO Yu-.Geochronology and Petrogeochemistry of Metallogenic Intrusions in the Shanmen Large-scale Silver Deposit in the Siping Area of Jilin Province,NE China)[J].地质学报（英文版）,2022(05):1631-1646

Petrogeochemistry,Intrusions,Shanmen,Siping,ascension

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