西藏班公湖-怒江成矿带西段与南美洲安第斯型超大型矿床成矿条件对比研究

Study on the comparing the mineralization conditions between the western part of the bangong lake-nujiang metallogenic belt in Tibet and the Andean super-large deposits in South America

西藏班公湖-怒江成矿带西段近年来取得重要的找矿突破,找矿前景好。班公湖带北部岛弧带与南美洲安第斯带具有相似的构造背景-大陆边缘弧,岩浆岩性质有可比性。班公湖带和安第斯带成矿岩浆的源区都显示具有大量地幔物质的加入,呈现相同的成矿趋势,即俯冲晚期成矿规模最大、地幔物质加入最多,且两者成矿组合具有相似性,都发育俯冲阶段的矽卡岩和斑岩型相关的Fe-Cu-Au矿床。但是,安第斯带新生代成矿斑岩形成于地壳较厚的背景下,显示埃达克岩的特征,而班公湖带成矿斑岩形成于正常地壳厚度背景下,班公湖带和安第斯带的矿床都显示受控于平行弧断裂和切弧断裂交汇处。综合对比研究认为,班公湖-怒江成矿带北段与安第斯超大型矿床成矿带有可比性。

An important prospecting breakthrough with a good prospect for finding mine has been achieved in the western part of the Bangong Lake-Nujiang metallogenic belt in recent years. There is a similar structural background between the continental margin arc in the Andean belt and the island arc belt in northern Bangong Lake zone and their magmatic rock properties are both the Bangong Lake zone and the Andean belt the same mineralization trends, such as the largest comparable. The source regions of the ore-forming magma in showed an addition of a large amount of mantle material and mineralization scale at the late subduction, adding the largest amount of mantle material, a similar mineralization assemblage between two belts and the development of skarn and porphyry-related Fe-Cu-Au material deposits at subduction stage in both belts. However, the Cenozoic metallogenic porphyry formed on the background of thick crust characterized by Adakite in the Andean zone while the metallogenic porphyry in Bangong Lake belt formed on the background of normal crustal thickness. The material deposit has been controlled by the intersect point of parallel arc fracture and tangential arc fracture in both Andean belt and Bangong Lake belt. The Comprehensive comparison study showed that the northern section of the Bangong Lake - Nujiang metallogenic belt was comparable with the Andean super-large deposits metallogenic belt.