Geological Characteristics and Metallogenic Model of the Orogenic-type Gold Deposit in South Qinling：A Case of Xiajiadian Gold(Vanadium) Deposit, Shanyang County, Shaanxi Province

On the basis of summing up geological setting and feature of Xiajiadian gold deposit, Shanyang County, Shaanxi province, this paper researched ore-controlled factors, statistic distribution law of ore-forming elements, metallogenic fluid characteristics, isotope features, and created a metallogenic model of this gold deposit. The gold ore body is mainly controlled by ore-bearing rock series and secondary fault in Zhen'an-Banyanzhen fracture. From surface to deep, the grade and thickness of gold ore show wave transformation, and display thinning out and recurrence in trend. Its fluid inclusion mostly consists of gas-liquid two-phase, which is featured by rich CO₂ (10%) and low salinity (3%—5%). The homogeneous temperature of main mineralization period concentrates between 240-280 ℃, and the metallogenic depth is 3 km. Isotope analysis indicates that metallogenic fluid mainly derives from mix of meteoric water and formation water, with a small part from the deep. In view of the findings, we founded a metallogenic model of Xiajiadian gold deposit, and concluded that the gold mine was predominantly a tectonic-fluid deposit of orogenic-type, which formed by the sedimentation of mineral substances cyclically leached from ore source bed by underground hot brine driven by geothermal or magma.