Volcanic Activity and Geochemical Processes in Oceanic Hotspot Systems

Oceanic hotspot systems arise where mantle plumes ascending from deep within the Earth penetrate oceanic lithosphere, generating magmatism that forms volcanic islands, seamount chains and submarine plateaux. Magma production at these sites is governed by decompression melting of heterogeneous mantle sources, producing lavas that record variations in temperature, pressure and composition. Once melts ascend, they may stall in crustal reservoirs, differentiating by crystallisation and assimilation of wall rock, or migrate laterally through dykes and sills to the surface. Hydrothermal circulation driven by volcanic heat alters host rocks and redistributes chemical species, creating enriched fluid plumes and mineral deposits. The interplay of magma dynamics, structural evolution and fluid–rock interaction not only shapes island edifices and collapse hazards but also modulates volatile release and elemental cycles in the ocean–atmosphere system. Understanding these processes is vital for hazard assessment, geothermal exploration and biogeochemical flux budgets in the marine environment.

Research from Nature Portfolio

Recent studies have introduced a non-invasive geochemical approach based on cold-water sampling to detect blind hydrothermal systems beneath oceanic volcanoes, using trace‐element and stable-isotope signatures to map subsurface fluid pathways. This method successfully located a hidden geothermal reservoir at a basaltic shield volcano, demonstrating its applicability to low-conductivity springs. In parallel, long-term analysis of satellite imagery coupled with inverse modelling of deformation has elucidated the subsurface architecture of a persistently active lava shield. Researchers revealed a spoon-shaped dyke–sill network extending seaward, through which repeated intrusions can trigger continuum displacement from elastic opening to pure slip, thus clarifying mechanisms that may lead to catastrophic flank collapse.

Volcanic Activity and Geochemical Processes in Oceanic Hotspot Systems publication trend

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

Technical terms

Oceanic hotspot: A region of anomalous, long-lived volcanic activity above a mantle plume below oceanic lithosphere.

Dyke: A vertical or steeply inclined sheet of magma that cuts through pre-existing rock layers during an intrusion event.

Sill: A horizontal or subhorizontal magma intrusion that intrudes parallel to bedding planes in the host rock.

Geochemical marker: A chemical element or isotopic ratio that indicates specific processes or source characteristics in magmatic or hydrothermal systems.

Interferometric Synthetic Aperture Radar (InSAR): A satellite remote-sensing technique that measures ground deformation by comparing radar phase differences over time.

References

1. Use of cold waters geochemistry as a geothermal prospecting tool for hidden hydrothermal systems in Réunion Island. Communications Earth & Environment (2024).
2. 22 years of satellite imagery reveal a major destabilization structure at Piton de la Fournaise. Nature Communications (2022).
3. The role of Interferometric Synthetic Aperture Radar in Detecting, Mapping, Monitoring, and Modelling the Volcanic Activity of Piton de la Fournaise, La Réunion: A Review. Remote Sensing (2020).