Chalcopyrite geochemistry: Advancements and implications in ore deposit research

Chalcopyrite is a prevalent sulfide mineral in ore deposits and hosts various trace elements such as Ag, Co, As, Se, Sb, Te, Bi, etc. The variations in trace element contents, as well as Fe, S, and Cu isotopic compositions of chalcopyrite are controlled by a series of factors including metallogenic temperature and pressure, fluid compositions, metal sources, and sulfide equilibrium. Therefore, chalcopyrite geochemistry offers valuable insights into the genesis of ore deposits. In this study, we reviewed and compiled the chalcopyrite geochemical data from porphyry Cu deposits (PCDs), sedimentary rock-hosted stratiform Cu deposits (SSCs), iron oxide Cu-Au deposits (IOCGs), sedimentary exhalative deposits (SEDEXs), magmatic Cu-Ni sulfide deposits (MSDs), and volcanogenic massive sulfide deposits (VMSs), etc. We aim to discuss and summarize the distribution and control mechanisms of trace elements and the compositional characteristics and controlling factors of S, Fe, and Cu isotopes in chalcopyrite, and the application of chalcopyrite geochemistry in ore deposit studies. Our study shows that different types of ore deposits show significantly distinct chalcopyrite geochemical characteristics. For example, in PCDs, chalcopyrite is notably enriched in Zn and Pb, with negative δ³⁴S values (−2.1 ± 3.64 ‰, n = 32) due to sediment contributions. Positive δ⁶⁵Cu values (1.5 ± 2.00 ‰, n = 140) indicate a mantle-crustal mixed source, while negative δ⁵⁷Fe values (−4.3 ± 5.10 ‰, n = 32) likely result from Fe isotope fractionation during magnetite precipitation or continental crust contamination. In MSDs, Cr is the most enriched element, with positive δ³⁴S values (1.0 ± 2.14 ‰, n = 185) and slightly negative δ⁶⁵Cu values (−0.46 ± 0.50 ‰, n = 52). Chalcopyrite in SSCs is enriched in Zn and As, characterized by negative δ³⁴S (−3.6 ± 0.12 ‰, n = 190) and δ⁶⁵Cu values (−0.59 ± 0.98 ‰, n = 118). These findings indicate that chalcopyrite can be used as an impactful tool for constraining metallogenic physical and chemical conditions, discriminating ore deposit types and tracing the evolution of ore-forming fluids and metal sources.