| The West Qingling gold belt is a important ore district in west china, it has found over fifty different scales gold deposits(and mine spots),and becomes an ideal place for the gold deposit theory study and exploration. Yang Shang gold belt becomes the focus and hot spot of the research in this place for its large reserves, sectional output, complex metallogenic law and a series of other features.Anba gold deposit has the most gold resource in the Yangshang gold belt, it becomes the first choice of study because of its high degree of exploration and the most abundant information. This article has used many subject theory and approach, like ore deposit geology and tectonic geochemistry, to study this deposit, also has analyzed and summarized the metallogenic background, geological characteristics, deformation characteristics, the tectonic geochemical characteristics and metallogenic mechanism, we have got those major recognitions:1.The Anba gold deposit has a close relationship with Mianlue tectonic belt’s complex material resources and tectonic evolution, the output of the ore deposit is controlled by multilevel structure, Wen xian arc structure is the most important regional ore controlling structure, and the Anchanghe-Guanyinba fault zone is the direct ore host structure.2. The ore bodies mainly occur in the Devonian starta and Triassic dikes, they show clustering zoning concentrate output, and the ore bodys show very obvious equidistant echelon. The ore type mainly includes altered phyllite type and altered dykes type, the main gold bearing mineral includes pyrite,arsenopyrite,stibnite,but the gold is invisible.The wall rock alteration scope is wide, showing no obvious zoning, the alteration type includes silicification, sericitization,carbonation,clay and others, they most belong to medium-low temperature alteration. Mineralization stages include sedimentary metamorphic phase, thermal ore forming phase and surface oxidation phase.3. The main structural features within the deposit are faults and folds, faults are the main parts of the ore body occurrence, fracture is controlled by fold. Structure mainly is brittle deformation, also has a little ductile deformation, the entire mining area is characterized by ductile brittle- brittle deformation characteristics.4. Ore controlling structure type in this deposit is divided into fracture zone type and contact zone type, their yield occurrence difference is not big, but the former is more intense carbonation, the latter is more intense sericitization. On the characteristics of constant element, they both show loss of K, Na, but the fracture zone type have more Ca,Mg.The mass balance calculation shows that most elements were gains, and the migration of elements in the contact zone is generally larger than that of the fracture zone.5. The structure not only plays the role of guiding ore deposit, but also affects the activation and migration of elements. The structure affects the metallogenic by coupling of fluid, permeability, reaction rate, fluid component saturation and other important metallogenic physical and chemical parameters. |
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