Mineralization and Formation Mechanism of Carboniferous-Permian Large-scale Magmatic Ore Deposits in Tianshan Orogenic Belt and Adjacent Area, Xinjiang

Geological tectonic evolution is complicated in Tianshan orogenic belt, and its magmatism and mineralization were disequilibrium among multi-stage evolution. But the period of Carboniferous-Permian was a high outbreak stage of large-scale magmatism and mineralization. This study focused on magmatic Ni-Cu sulfide deposits, porphyry copper deposits and volcanic type magnetite deposits, researched geological process of deep magma activity through magma origin, magma evolution and mineralization characteristics of ore-bearing rocks. Through deep analysis on typical deposits, this paper established metallogenic models for different deposit types, revealed controlling factors that restricted prospecting breakthrough, systematically expounded geological characteristics and mineralization features of tectonic coexistence of plate and mantle plume. Considering magma activity and mineralization characteristics of Tarim mantle plume, the authors built up relationships among three main types of deposits in Tianshan orogenic belt. Comparing their petrology, chronology and geochemistry, we found that there was close relationship between mineralization types of Tianshan orogenic belt and Tarim mantle plume; maybe it is a result of coexistent plate and mantle plume. The melt mantle material from the deep of Tarim craton upwelled along the margin of rigid Tarim craton, and exchanged with supracrustal material. The deep mantle material strengthened constantly with sustenance and weakening of subduction zone, and finally, formed respectively different types of ore deposits because of the variance of deep mantle material content. The establishment of this mantle plume model for deep process and mineralization can immensely promote the study on plate, mantle plume, magmatism and mineralization, at the same time, it also guide the regional prospecting work.