Metallogenic regularity and main research progress of cobalt and nickel deposits in China

Nickel (Ni) and cobalt (Co) are recognized as critical strategic metals by major industrialized nations. In recent years, substantial advancements have been achieved in Ni-Co resource exploration within China, generating a promising prospect for future discoveries. This review provides a comprehensive analysis of significant Ni and Co mineralization events in China, covering metallogenic provinces, deposit types, metallogenic epochs, and associated tectonic settings. Sedimentary Co deposits predominantly formed during the middle Paleoproterozoic (2200-1800 Ma) and early Mesoproterozoic (1600-1400 Ma) ages. In contrast, magmatic Ni-Co and hydrothermal metasomatic Co deposits are concentrated in the early Neoproterozoic (1100-700 Ma) and Paleozoic (220-430 Ma) ages. The intricate correlation between magmatic Ni-Co and hydrothermal metasomatic Co mineralization is linked to the evolution of primitive komatiitic and tholeiitic basalts. The formation of mineralized mafic-ultramafic intrusive rocks is identified as a key factor in the formation of magmatic Ni-Cu sulfide deposits, with the exception of sedimentary Co deposits, which represent a distinct geological event. The primary source of Ni-Co deposits in China can be attributed to a pyroxene-enriched mantle magma source. This is supported by platinum-group element (PGE) characteristics of magmatic Ni-Co deposits, which consistently indicate mineralization associated with partial melting processes within the mantle. Furthermore, sulfur (S) and rheniumosmium (Re-Os) isotopes in magmatic Ni-Co deposits reveal that crustal materials played a significant role in sulfur saturation during magmatic differentiation and mineralization. Ni-Co resources in China primarily consist of orogenic Ni-Co deposits, intricately linked to the multi-stage orogenic events that shaped the region's geological history. The orogenic Ni-Co system in China exhibits a distinctive profile marked by multi-stage and diversified mineralization. This includes the accumulation of Ni metal through prior mineralization events and the subsequent superposition of Co within pre-existing ore belts, reflecting complex geological processes and interactions. This review aims to contribute to a comprehensive understanding of Ni and Co resources in China, facilitating future exploration and resource management strategies.