Volcanic Processes in Oceanic Island Systems

Oceanic island volcanism arises where mantle plumes or intraplate stresses generate magma beneath thin oceanic lithosphere. Partial melting of enriched mantle sources produces basaltic magmas that ascend through a multilayered plumbing system, often involving deep mush zones and shallow crustal reservoirs. Magma evolution is governed by crystal fractionation, volatile exsolution and intermittent recharge from deeper chambers, giving rise to variable eruption styles from effusive lava flows to explosive tephra emissions. Degassing of CO₂, H₂O and sulphur species controls eruption energetics and atmospheric input, while magma ascent rates and storage depths influence hazards such as flank collapse or rapid dome growth. Advanced geophysical methods—seismic tomography, magnetotellurics and InSAR—and high-resolution petrology now allow real-time imaging of magma pathways, volatile budgets and subsurface structures. Understanding these processes is vital for hazard mitigation, geothermal exploration and quantifying volcanic contributions to global carbon cycles.

Research from Nature Portfolio

Recent studies have illuminated the dynamic architecture of magmatic systems beneath oceanic islands. High-precision relocation of thousands of earthquakes beneath La Palma has revealed a complex two-tier reservoir system: a mid-crustal mush zone overlain by a shallow, well-defined magma cavity. Seismic tomography indicates that magma can ascend from the base of the oceanic crust to the surface in under a week, emphasising the need for rapid monitoring. Concurrent gas emissions analyses from the 2021 Cumbre Vieja eruption demonstrate extraordinarily high CO₂/SO₂ ratios, implying magmatic CO₂ contents exceeding 4 wt % and total eruptive CO₂ releases on the order of 10⁷ t. These findings confirm that intra-plate alkaline magmas can rival large igneous provinces in cumulative carbon output and underscore the role of oceanic islands in volatile cycling.

Research from all publishers

High-resolution geochemical analyses of erupted products show that discrete pulses of primitive melt inject into shallower reservoirs, driving changes in eruption style and effusion rates. Strontium isotope variations and microcryst textures track successive intrusions of basanite, linking seismicity, SO₂ flux and lava discharge to specific magma injections. Complementary melt-inclusion studies from Fogo volcano reveal exceptionally volatile-rich magmas (up to 2 wt % CO₂ and 3 wt % H₂O) stored at mantle depths. Such magmas are oxidised and ascend rapidly via deep CO₂ exsolution, accounting for explosive intraplate eruptions. Noble gas and carbon isotope profiles in melt inclusions and fumaroles further constrain degassing trajectories from ∼80 km depth to surface, offering a model for source heterogeneity and crustal overprint in ocean island basalts.

Volcanic Processes in Oceanic Island Systems publication trend

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

Technical terms

Magmatic plumbing: The network of magma sources, reservoirs and conduits beneath a volcano.

Seismic tomography: A method using earthquake waves to image subsurface structures.

Melt inclusion: A small pocket of melt trapped within a crystal, preserving volatile and chemical signatures.

Volatile exsolution: Release of dissolved gases from magma as pressure decreases during ascent.

Magma mush: A partially crystalline reservoir where crystals and melt coexist over extended periods.

CO₂/SO₂ ratio: The proportion of carbon dioxide to sulphur dioxide in volcanic gas, indicative of magma source and evolution.

Plume buoyancy flux: A measure of the heat and material supplied by a mantle plume to the lithosphere.

References

1. Magmatic plumbing and dynamic evolution of the 2021 La Palma eruption. Nature Communications (2023).
2. Rapid magma ascent beneath La Palma revealed by seismic tomography. Scientific Reports (2022).
3. Exceptional eruptive CO2 emissions from intra-plate alkaline magmatism in the Canary volcanic archipelago. Communications Earth & Environment (2023).
4. Discrete magma injections drive the 2021 La Palma eruption. Science Advances (2023).
5. The helium and carbon isotopic signature of Ocean island basalts: Insights from Fogo volcano (Cape Verde archipelago). Earth and Planetary Science Letters (2024).
6. Oceanic intraplate explosive eruptions fed directly from the mantle. Proceedings of the National Academy of Sciences of the United States of America (2023).