Major types, spatio-temporal distribution, and metallogenesis of magmatism-related polymetallic deposits in the Bangonghu–Nujiang metallogenic belt, Tibet

Abstract

The Bangong–Nujiang metallogenic belt (BNMB) is one of the vital metallogenic belts in the Tibetan Plateau. At present, the metallogenic regularity on the scale of the whole metallogenic belt is still poorly understood. In this contribution, the geological, geochronological, geochemical, and isotopic data of 87 magmatism-related polymetallic deposits in the BNMB have been systematically collected to summarize the metallogenesis of polymetallic deposits in this belt. Our research shows that different segments of the BNMB have distinct metallogenic differences. The western, central, and eastern segments of the BNMB are characterized by the development of abundant Cu–Au, Fe–Cu–Cr–Ni, and W–Pb–Zn deposits, respectively. These various types of magmatism-related polymetallic deposits in the BNMB were formed between 188 Ma and 76 Ma, and the mineralization has two peak periods of 125–110 Ma and 90–75 Ma. The spatio-temporal variation of different types of magmatism-related polymetallic deposits in the BNMB is likely to be constrained by the lithospheric architecture and deep geodynamic processes. The elemental and Sr–Nd–Hf–S–Pb isotopic results indicate that various kinds of mineralization are closely related to relevant magmatism. The Cu–Au mineralization is related to dominantly mantle-derived, highly-oxidized, and less-evolved granitic intrusions; the Pb–Zn–W mineralization is genetically associated with dominantly ancient middle–upper crust-derived, relatively reduced, and highly-evolved granitic intrusions; the characteristics of the ore-causative intrusions related to Fe–Cu–Mo polymetallic mineralization are between those of the above two end members. In combination with previous studies, we propose a comprehensive model that includes four stages (>145 Ma, ∼145–125 Ma, ∼125–105 Ma, and ∼105–74 Ma) to illustrate the Jurassic–Cretaceous tectonic–magmatic–metallogenic evolution history in the whole BNMB.