Isotope geochemical characteristics of the Zhibo iron deposit in western Tianshan Mountains, Xinjiang

The Zhibo iron deposit is located in eastern Awulale metallogenic belt of Western Tianshan Mountains.The orebodies of the Zhibo iron deposit are hosted in basaltic andesite of the Lower Carboniferous Dahalajunshan Formation in layered, quasi-lamellar and lenticular forms.The mineralization process of the Zhibo iron deposit can be divided into two metallogenic periods, i.e., magmatic period and hydrothermal period, which consist of three metallogenic stages:magnetite + diopside, magnetite + K-feldspar + epidote and quartz + sulfide + carbonate stages.The geochemical characteristics of the Zhibo iron deposit show that its metallogenic tectonic setting was an island-arc environment.The geochemical data support derivation of volcanic rock and magnetite ore from basaltic magma formed by partial melting of depleted mantle wedge altered by fluids in subduction zones, with the same material source.The Zhibo iron deposit is a magmatic(mainly)-hydrothermal(subordinately) deposit.The basaltic magma intruded upward along deep fault and formed the primitive volcanic rock.Because of the change of physical-chemical conditions during its intrusion, the iron ore slurry was liquidized from the basaltic magma.The intrusion of the iron ore slurry into primitive volcanic rock might have been responsible for the formation of the magmatic type magnetite orebody and the alteration of the surrounding rocks by the residual magmatic hydrothermal fluid for the formation of the hydrothermal type magnetite orebody.