义敦弧北段首次发现大型中硫化型浅成低温热液富金银铅锌铜矿床OA

The Xia'nanggou deposit is a newly discovered Au-Ag-Pb-Zn-Cu mineralization system in the northern segment of the Yidun Arc(SW China).Based on integrated field mapping,drill core logging,petrographic observations,and shortwave infrared(SWIR)spectral analysis,we documented its geological characteristics,ore control,and genetic type.Orebodies occur as steep,tabular to pipe-like shoots hosted by Upper Triassic Mengge Formation tuffs and are jointly controlled by NW-trending faults and a concealed phreatomagmatic breccia pipe.The ore textures include veinlet-stockwork-disseminated,brecciated,and massive styles.The principal sulfide assemblages are sphalerite,galena,chalcopyrite,tetrahedrite,and tennantite.The alteration is well-zoned,with an inner silicification-sericitization core grading outward to a sericite-argillic zone and a distal propylitic halo,and the dominant alteration minerals are quartz-carbonate-muscovite-illite.A vertical metal zonation was observed from Pb-Zn in the shallow levels to Cu-Pb-Zn at intermediate depths and Cu(with elevated Au and Ag)at depth.Collectively,these features indicate an intermediate sulfidation epithermal system.This discovery expands the recognized deposit spectrum of the northern Yidun Arc and suggests a potential for porphyry-epithermal metallogenic systems within Late Triassic volcanic sequences.