西昆仑孜洛依铁矿床地质特征、形成时代及矿床成因探讨OA

The Ziluoyi iron deposit is the largest magnetite deposit in the northern segment of the Taxkorgan iron ore belt in the western Kunlun orogen,Xinjiang.Layered and stratoid orebodies are hosted in the meta-vol-canic-sedimentary rock series of the Bulunkuole Group and show conformable contacts with host rocks.The magnetite ores feature banded structures with two dominant mineral assemblages of magnetite-actinolite-biotite and magnetite-carbonate(calcite+dolomite)-biotite,showing notable differences in ore characteristics relative to deposits in the southern segment of the Taxkorgan iron-ore belt.Nevertheless,compared with the well-docu-mented deposits in the southern segment,knowledge of the Ziluoyi iron deposit,including its geological fea-tures,formation age,and genetic type,is still limited.In this study,the geological features of the Ziluoyi iron de-posit are dissected in detail.Zircon U-Pb geochronology and trace-element analyses on hanging-wall and foot-wall rocks conformable with iron orebodies are carried out to constrain their formation age and unravel their tec-tonic setting and genetic type.Using the youngest detrital zircon age(518±16 Ma)from ore-foot-wall metasedi-mentary rocks and the weighted-mean magmatic zircon age(504.3±5.9 Ma)from hanging-wall metadacite,the deposit's metallogenic age is constrained to the Cambrian Series  2-Miaolingian(518-504 Ma).Detrital-zircon age-peak patterns and magmatic zircon trace-element signatures from meta-dacite indicate that the protoliths of the Bulunkuole Group in the Ziluoyi area were generated within a fore-arc extensional setting.They predomi-nantly consist of arc volcanic rocks and sedimentary rocks derived from continental-arc magmatic materials of the Mazar-Tianshuihai terrane.Combining its metallogenic age,tectonic setting,and geological characteristics,we suggest that the Ziluoyi deposit originated from exhalative-sedimentary processes linked to marine volcanic rocks or submarine volcanic-hydrothermal systems.Located distally from submarine volcanic conduits or hy-drothermal vents,the deposit underwent high-greenschist-facies metamorphism after iron precipitation.