Metallogeneses in the collisional orogen of the Qinghai-Tibet Plateau：Tectonic setting, tempo-spatial distribution and ore deposit types

Abstract：Metallogeny of continents is an important research frontier in the contemporaneous metallogenic study, and its theoretical framework is conceived and established by gaining a deep knowledge and understanding of metallogeny in the continental collisional orogen. For a long time, geologists cannot reach a common view on the stages of collisional metallogeny and dynamic process in various stages because of a poor understanding of metallogeny in typical collisional orogens and coupling and genetic relations between the collisional orogenic process and crust/mantle interaction on the one hand and metallogenesis on the other. The Qinghai-Tibet Plateau orogen, which is characterized by the occurrence of large-scale, intense and young mineralization as well as many types of large and well-preserved deposit, is regarded as an ideal natural laboratory for studying ore-forming processes on continents and solving the above-mentioned problems. Through three years of systematical research on the metallogeny in the collisional orogen of the plateau, our project team has established a temporal-spatial framework of major mineralization events on the plateau, proposed a model of geodynamics and tectonic constraints on the ore-forming processes and put forward a set of complete theories on metallogeny in the collisional orogen. Three ore-forming processes and twelve deposit types are proposed in the new theories；they are：(1) metallogeny in the period of syn-collisional orogeny (65–41 Ma, four deposit types)；(2) metallogeny in the period of late-collisional transformation (40–26 Ma, four deposit types)；and (3) metallogeny in the period of post-collisional crustal extension (25–0 Ma, four deposit types). The corresponding key factors controlling the ore-forming processes are：(1) collisional orogenic setting, crustal magmatic activity and large-scale shear deformation;(2) intercontinental plate transformation setting, mantle-derived magmatic activity and large-scale strike-slip motion-nappe thrusting-shear deformation；and (3) post-collisional crustal extension setting, crust/mantle magmatic activity and hydrothermal convection system.