赣西北狮子岭花岗岩型锂矿床成因:来自岩石地球化学和锆石U-Pb年代学的约束OA北大核心CSTPCD

The ore cluster in northwestern Jiangxi Province is a significant granite-type lithium mineral resource base which is characterized by multi-stage magmatism and large-scale mineralization of rare metals like lithium.The granitic magma and rare-metal mineralization are intimately connected,then we further study the evolution char-acteristics of granitic magma in this area and its relationship with rare metal mineralization,define the petrogenic age and genetic types of related granites,and find out the mechanism of rare metal mineralization.In this study,the Shiziling granites in Jiuling area were selected as the research object,petrography,zircon U-Pb geochronolo-gy and petrogeochemistry analysis of the granites were carried out.Results show that the Shiziling gra-nites are high-K calc-alkaline series,and rich in Si and P,deplete in Ca,Mg,and Fe.Moreover,these rocks enrich in the high field strength elements(HFSE,e.g.,U,Hf),and deplete in the large-ion lithophile elements(LILE,e.g.,Ba,Sr).The rocks have lower total rare earth elements(REE),range from 2.12×10-6 to 146.24×10-6.The ratio of LREE/HREE is relatively high(3.5～16.53).The rocks show weak negative Eu anomalies(δEu=0.23～0.59).Overall,the Shiziling granites have geochemical characteristics of S-type granite.The zircon U-Pb dating results show that the petrogenic age of biotite monzogranite is(141.02±0.59)Ma,and the lepidolite(muscovite)alkali feldspar granite is(113.96±0.72)Ma.Amblygonite and lepidolite minerals formed in the petrogenic process of le-pidolite(muscovite)alkali feldspar granite,so the petrogenic age of alkali feldspar granite could be regarded as the metallogenetic age of rare metals.Rare metal mineralization was influenced by the Early stage of Yanshanian magmatic crystallization differentiation and the late hydrothermal metasomatism,magmatic crystallization differ-entiation is the determinants for the mineralization of Li,Nb,and Ta mineralization,hydrothermal alteration in the late stage provides the conditions for the secondary enrichment of Li.