Geophysical exploration strategy for Cu-Ni-Co deposits in China: A review

ABSTRACT Nickel (Ni) and Cobalt (Co) deposits are important mineral resources, and China is the largest consumer of these resources. Magmatic, hydrothermal, sedimentary, and meta-sedimentary ore-bearing rocks are the most significant Co-Ni deposit types in China, accounting for 98% of the Co production. Thus, exploring the Chinese Co-Ni resources and reserves is beneficial for promoting its economic development. We have analyzed the metallogenetic geologic model and the physical characteristics of the rocks and ores of magmatic Co-Ni sulfide and hydrothermal Cu-Co deposits and the sedimentary and meta-sedimentary rocks that host the Cu-Co ore deposits to develop an effective geophysical exploration technology system. For magmatic deposits, the small ore-forming intrusion is the main detection target; in general, gravity, magnetic, and seismic exploration and artificial-source electromagnetic methods are widely used to determine the precise location of the ore-forming intrusion. For hydrothermal deposits, ore-controlling structures and favorable positions for mineralization (e.g., alteration belts) are the main exploration targets, and the combination of hyperspectral remote sensing, gravity, magnetic-excitation, chemical prospecting, and artificial-source electromagnetic detection techniques can help locating such ore body types. For sedimentary and meta-sedimentary ore-bearing deposits, a combination of soil debris geochemical exploration measurement, induced polarization (IP) scanning, gravity method, IP sounding, and the transient electromagnetic method has been used to scan and locate the ore-controlling and ore-bearing layers. Finally, upon selecting the Xiarihamu magmatic Co-Ni deposit in the East Kunlun orogenic belt as our study area, we have conducted controlled-source electromagnetic exploration and obtained reliable results. Our study can serve as a reference for determining the most effective geophysical technique for the exploration of Cu-Ni-Co deposits in China.