Ore-forming geological background of the Tianshan Mountains-Pamir region in Central Asia

The Tianshan Mountains-Pamir region is located in the hinterland of Eurasian continent and in the junction of Kazakhstan-junggar, Karakum-Tarim, Central Iran-Gandise and Indian plate. It extends across two global tectonic domains, Tethys and Paleo-Asian Oceans, thus possessing complicated tectonic phenomena and rich mineral resources. Since Middle Neoarchean (or Proterozoic)the study area has experienced five main evolutionary phases. The continental nucleus in this area might have served as a part of “Pangea-Ⅳ” during Archean-Paleoproterozoic evolutionary phase. The first large-scale mineralization in Western Kunlun area was caused by continental breakup in the Changcheng-Qingbaikou period. At the Neoproterozoic supercontinental convergence stage, Vendian carbonaceous rock series was extensively deposited in Middle Tianshan Mountains, which served as the source bed of gold and provided a material basis for large-scale gold mineralization in the following evolutionary phase. Magmatic activities occurred intensely during the Neoproterozoic supercontinental breakup period as well as the evolutionary stage of Paleo-Asian Ocean and Tethys, with frequent exchange of deep crust-mantle material, especially in Late Devonian - Early-Midle Permian post-collisional intraplate extension phase, which seems to have been the most important ore-forming stage in the study area. As the study of this area remains at a very low level (some part in the study area even has no geological work), few mineral deposits of the Tethys evolutionary stage have been discovered in spite of the fact that this area owns considerable prospecting potential. Following the strong tectonic activities in this area, such as crumpling, folding, lifting, striking-slipping and thrusting, magmatic activities occurred widely at the post-orogenic stage after the formation of Eurasian continent. As a result, there occurred a series of gold mineralization related to ductile shear structures, as well as iron, copper, multi-metal, lithium, beryllium (niobium, tantalum), tungsten, tin, molybdenum and other minerals related to acidic magmatic hydrothermal activities.