The Geological and Geochemical Characteristics of the Intrusive Rock and Prospecting Significance in Shaqiu Areas, Qimantage Metallogenic Belt, Qinghai Province

Restricted by the cover of desert, the prospecting in Shaqiu area of Qimantage metallogenic belt is rather difficult. Recently, a number of iron-polymetallic deposits of skarn type have been explored. Study on intrusive rocks related to mineralization in this area is conducted. Based on the findings, it is concluded that granodiorite-monzonitic granite was the typical intrusive rock assemblage closely connected to mineralizing, with the same petrotectonic assemblage characteristics in Hutouya, Yemaquan and Sijiaoyanggou deposits. From early period to late period, compositions of intrusive rocks gradually enriched in SiO₂ and K₂O, but reduced in TiO₂, Al₂O₃, Fe₂O₃, FeO, MnO, MgO, CaO and P₂O₅. The differentiated degree and Eu-deficit get stronger while the ratio of Na₂O and K₂O is reducing. Belonging to rocks of I-type, these intrusive rocks possess features in terms of tectonic setting similar to those in collision stage. The magma source region in Shaqiu area has some explicit contribution to mantle-derived substances, especially to gabbro diorite and granodiorite, which is favorable mineralization geological condition for large-sized ron-polymetallic deposits of skarn type. With the progression of mining exploration, major prospecting breakthrough will probably be made.