Volatile Dynamics in Magmatic Systems

Volatile dynamics in magmatic systems encompass the behaviour of low-molecular-weight components—principally H₂O, CO₂, S and halogens—within silicate melts from their source in the mantle to eruption at Earth’s surface. Solubility of these species is pressure- and temperature-dependent, governing exsolution during decompression and crystallisation. The nucleation and growth of vapour bubbles influence magma rheology, drive ascent rates and modulate eruption style. Post-entrapment processes within crystal-hosted melt inclusions can alter recorded volatile inventories, necessitating careful interpretation. On a planetary scale, magmatic volatile release shapes atmospheric composition and climate, while in near-surface contexts it informs volcanic hazard assessment and geothermal energy exploitation. Recent advances integrate high-resolution spectroscopic analyses, experimental petrology and numerical models to reconstruct pre-eruptive storage conditions, trace mantle source heterogeneity and predict degassing pathways under varying tectonic settings.

Research from Nature Portfolio

Investigations into mantle carbon reveal that CO₂ concentrations are highly heterogeneous, with measurements from undegassed melt inclusions indicating variations of nearly two orders of magnitude on a global scale. Such heterogeneity affects the depths at which melts become interconnected and modulates volcanic CO₂ fluxes at mid-ocean ridges. Complementary work on crystal scavenging demonstrates that primitive olivines entrain melt inclusions from long-lived mush zones, leading to compositional disequilibrium with carrier melts. Post-entrapment crystallisation driven by this scavenging process sequesters CO₂ into vapour bubbles, skewing barometric estimates unless both glass and bubble compositions are measured. Together, these studies underscore the importance of source heterogeneity and crystal cargo dynamics in interpreting volatile budgets.

Research from all publishers

Case studies of the 2018 Kīlauea eruption combine Raman spectroscopy and secondary-ion mass spectrometry to quantify CO₂ in both glass and vapour bubbles within melt inclusions. Inclusion-plus-bubble analyses yield entrapment pressures consistent with independently determined reservoir depths at 1–2 km and 3–5 km, reconciling petrological and geophysical observations. In parallel, the development of an open-source thermodynamic engine for mixed H₂O–CO₂ solubility in silicate melts enables automated processing of thousands of samples under varying P-T-X conditions. This tool integrates multiple solubility models, computes saturation pressures, degassing paths and supports in-tool plotting, thereby facilitating large-scale comparative studies of volatile behaviour across diverse volcanic settings.

Volatile Dynamics in Magmatic Systems publication trend

The graph below shows the total number of articles in volatile dynamics in magmatic systems across all publications each year (not limited to Nature Index journals).

Technical terms

Volatiles: Low-molecular-weight components (e.g. H₂O, CO₂, S) dissolved in magma that exsolve during decompression.

Melt inclusion: Pocket of trapped silicate melt within a growing crystal, preserving pre-eruptive volatile and chemical compositions.

Exsolution: Process by which dissolved volatiles separate from melt to form a distinct vapour phase.

Solubility: Maximum concentration of a volatile species that can be held in the melt under given pressure and temperature conditions.

Saturation pressure: Pressure at which a volatile species becomes saturated in the melt and begins to exsolve.

References

1. Heterogeneity in mantle carbon content from CO2-undersaturated basalts. Nature Communications (2017).
2. Crystal scavenging from mush piles recorded by melt inclusions. Nature Communications (2019).
3. Reconstructing Magma Storage Depths for the 2018 Kı̄lauean Eruption From Melt Inclusion CO2 Contents: The Importance of Vapor Bubbles. Geochemistry Geophysics Geosystems (2021).
4. VESIcal Part I: An Open‐Source Thermodynamic Model Engine for Mixed Volatile (H2O‐CO2) Solubility in Silicate Melts. Earth and Space Science (2021).