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.

The Sipingshan gold deposit, located in the eastern part of the Nadanhada Terrane, is hosted within cherts and silicified breccias of the Upper Cretaceous Sipingshan Formation and rhyolites of the Upper Cretaceous Datashanlinchang Formation. The orebodies are composed of gold- and pyrite-bearing cherts, silicified breccias, and quartz veins accompanied by various types of wall rock alteration, including silicification, pyritization, sericitization, chloritization, pyrophyllitization, and carbonatization. LA-ICP-MS U–Pb zircon ages determined for the ore-bearing rhyolites range between 122 ± 1.4 and 135.2 ± 1.9 million years slightly older than the metallogenic age of the Sipingshan gold deposit. The rhyolite has aluminium saturation index values ranging from 0.015 to 1.25 and shows the following features: enrichment in LILE (e.g. Rb, Pb, K, and Th); depletion of Ba, Sm, and Ti; and negative Eu anomalies. These geochemical characteristics indicate that (1) the rhyolite contains features typical of S-type granites; (2) the felsic magma likely originated through partial melting of the continental crust; and (3) plagioclase crystals were present in the partial melt residues in the magma source region, or else magma evolution involved plagioclase fractionation. The host cherts have high Al/(Al + Fe + Mn) ratios (0.23–0.81, averaging 0.60) and low Al₂O₃ and TiO₂ contents. Their North American shale-normalized REE patterns are characterized by flat REE, slightly positive Eu anomalies, no Ce anomalies, and (La/Yb)_SN ratios of 1.27–1.38, indicating that these cherts formed in a continental margin environment. In addition, the analysed cherts have low ΣREE (1.56–3.64 ppm) and Zr (9.1–13.5 ppm) contents, suggesting a hydrothermal origin. Fluid inclusions in quartz veins show elliptical to irregular shapes that range from 5 to 12 μm in size and have homogenization temperatures of 118.7–223.4°C, densities of 0.84–0.94 g/cm³, and pressures of 21.2–51.4 MPa, indicating that the hot-spring-type Sipingshan gold deposit is epithermal in origin.

The Duobaoshan (DBS)-Tongshan (TS) porphyry Cu–(Mo) deposit (4.4 Mt Cu, 0.15 Mt Mo) is located in the northeastern part of the central Asian orogenic belt (CAOB) in northeastern China. It is hosted by early Ordovician dioritic to granodioritic intrusions which are characterized by the subduction-related geochemical signatures including high concentrations of large ion lithophile elements (LILEs) and light rare earth elements (LREEs), and low concentrations of heavy REEs (HREEs) and high-field -strength elements (HFSEs), such as Nb, Ta, Zr and Ti in bulk rock compositions. Furthermore, they show adakitic geochemical signatures of high Sr/Y ratios (29~55) due to high Sr (290~750 ppm) and low Y (<18 ppm). Zircon trace element abundances and published Sr-Nd-Hf isotope data of these rocks suggest that the parental magmas for these ore-bearing intrusions were rich in H₂O and formed by partial melting of a juvenile lower crust/lithospheric mantle or metasomatized mantle wedge during the northwestward subduction of the Paleo-Asian Ocean before the collision of the Songnen block with the Erguna-Xing’an amalgamated block in the early Carboniferous. Values of Ce⁴⁺/Ce³⁺ and Ce/Nd in zircons are 307~461 and 14.1~20.3 for mineralized granodiorites, and 231~350 and 12.4~18.2 for variably altered diorite and granodiorites in DBS, whereas those for DBS-TS microgabbros are 174~357 and 7.4~22, and 45.9~62.6 and 5.0~5.8 for the early Mosozoic Qz-monzonites, respectively. Zircon Eu/Eu* values are high and similar among mineralized granodiorites (~0.6), altered diorite and granodiorites (~0.6) and the Mesozoic Qz-monzonites (~0.8), whereas the values are low and variable for the DBS-TS microgabbros (0.3~0.6). The magma oxidation state calculated from zircon chemistry and whole rock compositions are FMQ +1.0 to +1.5 in mineralized samples, and FMQ +2.4 to +4.2 in altered samples. The values are comparable to those for the fertile intrusions hosting porphyry Cu-Mo-(Au) deposits in the central and western CAOB and elsewhere in the world. Elevated oxidation state is also observed in the TS microgabbros, FMQ +1.4 to +1.9, and the early Mesozoic Qz-monzonites, FMQ +2.4 to +2.5. Comparison of zircon geochemistry data from porphyry deposists elsewhere suggests that positive Ce anomalies are generally associated with fertile intrusions, but not all igneous rocks with high Ce anomalies are Cu fertile. The findings in this study are useful in exploration work and evaluating oxidation state of magmas for porphyry Cu-(Mo) deposits in the region and elsewhere.