内蒙古下陶勒盖铁铜矿床成矿岩体地球化学特征及其成岩成矿启示OA北大核心CSTPCD

The Xiataolegai iron and copper deposit,located in Inner Mongolia,is a representative skarn-type deposit within the active continental margin of the Beishan Metallogenic Belt.Situated in the western part of the Ejina Banner in the Alashan League,it is closely associated in both time and space with granodiorite and monzo-granite linked to Fe-Cu mineralization.To ascertain the formation age,source characteristics,and the relation-ship between magmatism and mineralization,samples underwent petrography,geochemical analysis,and zircon U-Pb dating.Results reveal high SiO2,Al2O3,alkalinity,and low MgO,with LREE enrichment and HREE deple-tion in both granodiorite and monzogranite.Granodiorite exhibits Rb,La enrichment,Ta,Nb,Ti,P depletion,weak Ce positive and Eu negative anomaly,while monzogranite shows Rb,U enrichment,Nb,Ti,P depletion,Ce positive and weak Eu negative anomaly Both granodiorite and monzogranite are classified as calc-alkaline I-type granite.The obtained U-Pb ages for zircons from granodiorite and monzogranite are(451.7±4.8)Ma and(460.1±4.9)Ma,indicating that the magmatism and related mineralization in the eastern and western section of the deposit occurred in the Late Ordovician and Middle Ordovician,respectively.A comprehensive analysis sug-gests that the Xiataolegai deposit formed in the late-middle Ordovician within an active continental margin arc tectonic setting,likely associated with oceanic plate subduction.