| 其他摘要 | Yangshan gold deposit locates in Mianlue suture of West Qinling，on the boundary of Shaanxi, Gansu, Sichuan provinces, It's one of the world class super-large gold deposits in China. Former research mainly concentrate on the geology of deposit, geochemistry of stable isotope, isotope dating, etc., but the systemic research on the igneous rocks of this region is still a blank. In Yangshan gold deposit the ore body is tightly connecting with the igneous rocks, both on time scale and space scale. Therefore, a systemic research on the geochemistry character of igneous rocks at Yangshan gold deposit, would have significant meaning on analyzing the tectonic event, magma event, process of mineralization and establish the model of ore genesis.
This thesis base on the systemic research on igneous rocks of Yangshan gold deposit, corresponding with factors like geology of the deposit, character of geochemistry, tectonics etc., analyzing the petrology geochemistry character of the igneous rocks from Yangshan gold deposit, with major element, trace element and rare earth element. Realizations below are acquired from this research.
1 The igneous rocks at Yangshan gold deposit is calcium-alkaline peraluminous granitoid, during the term in the magma room or invasion, the magma behave a fractional crystallization trend.
2 At the No. 305 and 311 load group of Anba section, GeTiaoWan section and Nishan section (except the erode samples), the igneous rocks all have the same major element, trace element, rare earth element character, genesis of the igneous rocks from above 3 sections have tight connection.
3 The genesis of granite at Yangshan is mainly from element of crust, the outcome formed at the early subduction zone might also participate. After the element of deep crust partial melting, the granite formed after the final collision of Qinling micro-craton and Yangze craton, and Mianlue suture formed. Granite formed at the late stage of main collision, during the term of stress loosing. The collision event place a premium on the crust thicken, get the shale and clastic sandstone form crust rock close to melting temperature, then arouse partial melting by more heat and fluid added.
4 In the genesis model of Yangshan gold deposit, metamorphic fluid is the dominant fluid of mineralization, in different stage of mineralization a little surface-drived water, magmatic water and meteoric water interfused. |
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