Geochemical Characterization of Molybdenum Deposits in Orogenic Terranes

Orogenic terranes host a diverse suite of molybdenum deposits, ranging from porphyry systems to skarn and vein-type occurrences. Geochemical characterisation of these deposits integrates petrography, fluid inclusion studies and isotope geochemistry to unravel the sources, evolution and depositional mechanisms of ore-forming fluids. Key tools include trace-element distributions in accessory minerals, Re-Os dating of molybdenite, and H–O–C–S isotopic signatures to distinguish magmatic, metamorphic or meteoric contributions. High-pressure experiments and phase-equilibrium models constrain how CO2, H2O and saline components partition between melt and fluid, affecting Mo solubility and transport. In skarn settings, fluid–rock interaction at the contact between intrusions and carbonate sequences drives skarn mineralogy and Mo enrichment. Porphyry deposits in orogenic belts often form under oxidised conditions, with redox buffering by surrounding rocks influencing sulphide precipitation. Geophysical methods and microthermometry of fluid inclusions reveal P–T–X conditions throughout mineralisation stages, from deep magmatic exsolution to shallow boiling and mixing with external waters. Such integrated geochemical approaches have global significance for exploration, enabling predictive models of Mo endowments and guiding sustainable resource development in major orogenic provinces.

Research from Nature Portfolio

Recent studies have demonstrated that CO2-rich magmatic-hydrothermal fluids play a pivotal role in enhancing molybdenum transport and deposition in Dabie-type porphyry systems. Laboratory experiments at magmatic temperatures and pressures reveal that immiscible brine–vapour separation dramatically increases the partition coefficient of Mo into the brine phase, facilitating efficient extraction from crystallising felsic melts. These results clarify why certain orogenic porphyry deposits exhibit exceptionally high molybdenum grades, emphasising the influence of volatile composition on ore-forming processes.

Geochemical Characterization of Molybdenum Deposits in Orogenic Terranes publication trend

The graph below shows the total number of articles in geochemical characterization of molybdenum deposits in orogenic terranes across all publications each year (not limited to Nature Index journals).

Technical terms

Porphyry deposit: A large, low-grade copper-molybdenum deposit formed from magmatic-hydrothermal fluids percolating through fractured country rock.

Skarn: A metasomatic assemblage formed at the contact between igneous intrusions and carbonate-rich sedimentary rocks, often enriched in base and precious metals.

Fluid inclusion: Microscopic pockets of fluid trapped within minerals during growth that record pressure, temperature and composition of ore-forming fluids.

Stable isotopes: Non-radiogenic isotopic ratios (e.g., δ18O, δ34S) used to trace fluid sources and water–rock interactions.

Oxygen fugacity (fO2): A measure of the oxidation-reduction potential of a system, controlling valence states of sulphur and metal solubility in magmatic fluids.

Immiscible fluid: Coexisting separate fluid phases (e.g., brine and vapour) that partition solutes differently, influencing metal transport and deposition.

References

1. The role of CO2 in the genesis of Dabie-type porphyry molybdenum deposits. Nature Communications (2024).
2. Genesis of the Shibaogou Mo–Pb–Zn deposit in the Luanchuan ore district, China: Constraints from geochronology, fluid inclusion, and H–O–S–Pb isotopes. Frontiers in Earth Science (2023).
3. The Role of Reductive Carbonaceous Surrounding Rocks in the Formation of Porphyry Mo Deposits. Minerals (2023).
4. Spread Spectrum Induced Polarization (SSIP) Survey for the Qiushuwan Copper–Molybdenum Deposits in Southern Henan Province, China. Minerals (2024).