江西九岭南缘蚀变花岗岩型锂矿床成矿地质特征及找矿方向OA北大核心CSTPCD

In recent years,the Tong'an-Baishuidong area in the southern margin of Jiuling Mountains has made a ma-jor prospecting breakthrough,and many large and super-large altered granite-type lithium deposits have been dis-covered.A systematic summarization of the geological characteristics of lithium deposits in this area is of great significance for summarizing the regional metallogenic regularity and guiding the next prospecting and explora-tion.Based on detailed field geological survey and drill core record compiling,combining with previous research results,the Yanshanian granites in the southern margin of Jiuling are divided into four stages.The lithology from old to new are medium-fine-medium-coarse grained porphyritic two-mica monzogranite→medium-fine grained porphyritic(less-porphyritic)two-mica monzogranite → fine-grained two-mica monzogranite → medium-fine grained muscovite monzogranite.There are a clear intrusive contact relationship between the lithologys.Among them,the late stage muscovite monzogranite and lithium ore have metallogenic specificity,and often overlie other Yanshanian plutons,and there are xenolith of early pluton in the interior.The lithium ore body is delineated by w(Li2O)≥0.20%,and the ore body is mainly distributed in the medium and strong albitized muscovite monzonitic granite in the upper part of Baishuidong pluton.At the same time,there are a small amount of pegmatite and ap-lite ore bodies,and local granites surrounding rock are mineralized,but the lower weakly albitized muscovite monzonitic granite and surface local area muscovite monzonitic granites do not contain ore.Lithium mainly oc-curs in lithian muscovite and lepidolite,and gangue minerals are mainly albite,quartz,potassium feldspar,mica and so on.The alteration of Yanshanian granite is common and strong,and the alteration types mainly include po-tassium feldspathization,albitization,muscovitization(muscovitization of lepidolite),greisenization and topaziza-tion.Muscovitization(muscovitization of lepidolite)is manifested as muscovite and lepidolite formed by altera-tion around the edge of primary muscovite,and is closely associated with albitization.The mineralization mainly occurred in the alkali metasomatism stage,and locally superimposed with greisenization(acid metasomatism)stage.The above characteristics indicate that the altered granite-type lithium deposits in the southern margin of Jiul-ing are enriched and mineralized in the alkali metasomatic stage of hydrothermal action.Combined with the charac-teristics of stream sediment anomalies,the metallogenic elements of lithium deposits in this area were preliminarily summarized,and the prospecting signs were established.Chenjiali-Xin'anli,Gangkou-Dongkeng,Sanjiaoling-Dongwoli,Zhangjiali-Yaochangli and other places were delineated as the next key prospecting targets,which point-ed out the direction for the exploration of altered granite-type lithium deposits in the southern margin of Jiuling.