Metal transport by magmatic volatile phases in crustal systems

Journal article

Magmatic volatile phases (MVPs) are multicomponent fluids that are a transport medium for metals being transferred from deep magmatic sources to sites of ore formation. However, the melt-to-fluid exchange of metals remains elusive because existing empirical simulations primarily address metal transport through the fate of one chemical element. We use a comprehensive thermochemical model to simulate the fractional crystallization of a silicate melt that degasses a multicomponent MVP. We show that the major and trace element abundances in MVPs formed from non-enriched magmatic systems are indistinguishable from MVPs found as fluid inclusions in mineralized and non-mineralized systems. We therefore conclude that ore formation is the consequence of repetitive intrusion-fractionation-degassing cycles common to crustal systems without pre-enriched sources, as opposed to scenarios wherein a particular or complex chemical system is required. Instead, the driving force of ore formation is a long-lived system fueled by an H₂O- and Cl-bearing melt. Variations in metal signatures of fluids therefore reflect the pressure-temperature path of melt ascent and the changes in major element composition of the melt.

Authors: Gion, AM; Gaillard, F

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Geological Society of America
• Journal: Geology
• Volume: 54
• Issue: 5
• Pages: 399-403
• Publication date: 2026-02-02
• Acceptance date: 2026-01-20
• DOI: 10.1130/g54065.1
• EISSN: 1943-2682
• ISSN: 0091-7613
• Language: English
• Keywords: magmatic volatile phase; magmatic-hydrothermal; metal transport