Tethyan evolution and metallogenic geological background of the Bangong Co-Nujiang belt and the Qiangtang massif in Tibet

Early Paleozoic-Devonian sediments of the study area are mainly composed of shelf clastic rocks and platform carbonate, representing the northern margin of Gondwana and south Tethyan passive continental margin. Permian-Carboniferous archipelagos were formed to the south and north of the Tethyan ocean, resulting in the formation of magmatic arcs to the north of the Longmuco-Shuanghu belt and the south of the Jinshajiang and in the Gangdise zone one after another. Mesozoic archipelagos occurred to the south of the Tethyan ocean, where Cr, Ni and Pt group metallic type deposits of magmatic segregation occurred in the SSZ-type ophiolite. Petrological and geophysical evidence supports a bilateral subduction scenario that resulted in arc magmatism to the north and south of the Bangong Co-Nujiang suture zone. These magmatic arcs are the most important metallogenic belt for porphyry copper deposits, skarn-type magnetite deposits and hydrothermal polymetallic deposits. The Jurassic back arc and foreland basin to the northeastern Qiangtang favored the formation of depositional and hydrothermal alteration Fe-Cu-Sb-Au deposits. In the collisional stage of Late Cretaceous-Cenozoic period, hydrothermal deposits were widely distributed, and this stage was also a stage with the potential to form porphyry copper deposits.