This paper is the result of the mineral exploration engineering.

Objective Nickel and cobalt, as strategic and critical energy metal minerals, play a pivotal role in China's economic development and are the focal points of the new round of mineral exploration breakthrough strategies. There is an urgent need to investigate the available ore−forming types of nickel and cobalt, their ore−forming patterns, and exploration potential.

Methods Nickel and cobalt are mantle−derived elements with the highest concentrations found in olivine within mantle rocks. Virtually all minerals enriched in the upper crust that are exploitable by humans originate from the mantle, particularly from olivine. This paper, based on the actual production of nickel and cobalt minerals in China and in comparison with the characteristics of global nickel and cobalt mineral discoveries in recent years, proposes the most promising nickel and cobalt ore−forming types in China from the perspective of the country's metallogenic background and conditions. It conducts research on the ore−forming characteristics and the spatiotemporal distribution patterns. Building on this foundation, the study analyzes the metallogenic belts of significant nickel and cobalt ore−forming types, assesses their exploration prospects, and offers recommendations for further evaluation of mineral potential.

Results The ore−forming processes of nickel and cobalt in China can be categorized into two types: magmatic and hydrothermal. Magmatic ore−forming processes result in magmatic nickel and cobalt ore types, specifically those formed by magmatic immiscibility, such as nickel and cobalt sulfide deposits associated with komatiitic (ultramafic) magma and basaltic (mafic) magma. The former is rich in ore formation and rare in China, while the latter is the predominant type of magmatic nickel and cobalt sulfide deposits in China. Additionally, cobalt is associated with magmatic vanadium−titanium magnetite deposits. Hydrothermal ore−forming processes result in hydrothermal nickel and cobalt ore types, which are primarily sediment−hosted cobalt deposits, lateritic nickel−cobalt deposits, and vein−type cobalt deposits globally. In recent years, a significant amount of skarn, porphyry, and IOCG−type polymetallic ore deposits associated with cobalt has been discovered in the middle and lower reaches of the Yangtze River in China. There has been significant progress in the study of the ore−forming patterns of magmatic nickel and cobalt sulfide deposits, which are mainly formed in three periods (Neoproterozoic, early and late Paleozoic) and six metallogenic belts. Research on hydrothermal nickel and cobalt deposits is relatively weak.

Conclusions Magmatic nickel and cobalt sulfide deposits in China have a global advantage. In recent years, in addition to the discovery of the Xiariham super−large deposit, significant discoveries have been made around the Jinchuan super−large deposit. Magmatic nickel and cobalt sulfide deposits remain the primary ore−forming type for nickel and cobalt exploration breakthroughs in China. Concurrently, there is a need to intensify research on ore formation and exploration related to hydrothermal processes, such as sediment−hosted cobalt deposits, lateritic nickel−cobalt deposits, and vein−type cobalt deposits, to achieve exploration breakthroughs. It is also essential to develop economic and efficient comprehensive recovery and utilization of cobalt associated with existing significant skarn and porphyry−type copper−iron and other polymetallic ore deposits.