Hydrothermal Processes in Ore Deposit Systems

Hydrothermal processes are central to the formation of many of the world’s most important mineral deposits. These processes involve the migration of hot, aqueous fluids through the Earth’s crust, where they leach metals from magmatic sources, metamorphic envelopes or surrounding host rocks. Temperature, pressure, fluid composition and redox state jointly control the solubility and transport of metals in solution or as suspended particulates. Changes in these parameters—through cooling, decompression, fluid–rock interaction, mixing with external waters or phase separation into brine and vapour—trigger metal precipitation and mineral zonation that characterise porphyry, epithermal and intrusion-related systems. Fluid inclusions trapped in gangue minerals record these physico-chemical conditions and guide exploration. Understanding the dynamics of fluid flow, the roles of supercritical phases and metal-ligand complexation is essential for locating high-grade resources of copper, gold, silver and critical metals. Advances in numerical modelling and high-resolution imaging now allow reconstruction of transient processes such as melt droplet transport and boiling-driven brine formation. These insights have direct implications for sustainable exploration strategies and innovative extraction methods that may one day tap deep-seated brine lenses as in situ sources of metals and geothermal energy.

Research from Nature Portfolio

Recent studies have highlighted the mechanical transport of metal-rich melts within epithermal fluids at temperatures below 400 °C. Nanometre- to micrometre-scale sulphide-sulfosalt droplets suspended in hydrothermal fluids form polymineral inclusions that co-evolve with quartz-hosted fluid inclusions. Numerical models based on particle fluidization theory demonstrate that such nano-micromelts can travel significant distances before coalescing and depositing gold and silver. In parallel, advances in numerical hydrology quantify how vapour–brine separation, halite saturation and mixing with meteoric water dictate metal zoning in porphyry-epithermal transitions. Simulations reveal that higher magmatic fluid release rates favour halite saturation without marked zonation, whereas slower rates promote peripheral ore shells through mixing-driven precipitation and remobilisation of previously deposited metals.

Hydrothermal Processes in Ore Deposit Systems publication trend

The graph below shows the total number of articles in hydrothermal processes in ore deposit systems across all publications each year (not limited to Nature Index journals).

Technical terms

Hydrothermal fluid: A hot aqueous solution derived from magmatic, metamorphic or meteoric sources that transports dissolved minerals.
Fluid inclusion: A microscopic pocket of trapped fluid within minerals, preserving physico-chemical conditions of mineralisation.
Phase separation: The unmixing of a single fluid into distinct liquid (brine) and vapour phases under changing pressure and temperature.
Supercritical fluid: A state of fluid above its critical point exhibiting properties of both liquids and gases, enhancing metal transport.
Metal-rich melt: A suspension of nanoscale sulphide or sulfosalt droplets in fluid that can transport high metal concentrations.
Brine: A hypersaline fluid phase with elevated metal solubilities, commonly generated by fluid boiling or magmatic degassing.

References

1. Transient non-soluble noble metal transport in hydrothermal ore systems. Nature Communications (2025).
2. Hydrological controls on base metal precipitation and zoning at the porphyry-epithermal transition constrained by numerical modeling. Scientific Reports (2023).
3. The transport of bismuth in HCl-bearing aqueous vapour and low-density aqueous supercritical fluids: Implications for natural systems. Geochimica et Cosmochimica Acta (2024).
4. The economic potential of metalliferous sub-volcanic brines. Royal Society Open Science (2021).