Magmatic Processes in Icelandic Volcanic Systems

Iceland sits astride the Mid-Atlantic Ridge and above a long‐lived mantle plume, creating a unique laboratory for studying basaltic magmatism. Mantle upwelling beneath Iceland generates extensive decompression melting that yields high melt fluxes and thick crust. Magma segregation begins in the upper mantle and is modulated by compositional heterogeneity—plume‐derived melts mix with enriched and depleted mid‐ocean ridge basalt (MORB) components. As melts ascend, they undergo fractional crystallisation, volatile exsolution and open‐system mixing in crustal storage zones at depths ranging from near the Moho to shallow reservoirs. Lateral dyke propagation links central volcanoes to fissure swarms, enabling rapid magma transport and eruption. Detailed petrological, geochemical and geophysical studies reveal the timescales and pathways of magma evolution, from melt generation to surface eruption. Insights gained in Iceland have global relevance for mid‐ocean ridge systems, plume–ridge interaction and volcanic hazard assessment. Moreover, understanding magma storage and transport informs geothermal energy development, volcanic monitoring and eruption forecasting.

Research from Nature Portfolio

Recent studies of the 2021 Fagradalsfjall eruption on the Reykjanes Peninsula have illuminated mantle source characteristics and shallow crustal processing. One investigation of melt chemistry and oxygen isotopes found that, despite broad trace-element diversity signalling both plume and enriched MORB contributions, the erupted basalts share a uniform δ¹⁸O signature matching ‘normal’ upper mantle values. This establishes a regional isotopic reference for plume-ridge systems. Concurrent work combined petrology, gas emissions and geochemical proxies to track magma extraction from a near-Moho storage zone. Over weeks of eruptive activity, magmas sourced progressively from greater depths, offering an unprecedented temporal record of mantle melting conditions and melt‐lens dynamics beneath Iceland.

Magmatic Processes in Icelandic Volcanic Systems publication trend

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

Technical terms

Fractional crystallisation: The sequential removal of minerals from a cooling melt, altering its composition.

Mantle plume: A buoyant, upwelling column of hot mantle material that generates anomalously high melt production.

Mid-ocean ridge basalt (MORB): Basaltic magma produced by decompression melting beneath spreading ridges, typically depleted in certain trace elements.

Melt inclusion: A small pocket of melt trapped within a growing mineral grain, preserving pre-eruption magma composition.

Dyke propagation: The lateral intrusion of magma-filled fractures that transport melt through the crust to eruption sites.

References

1. Diverse mantle components with invariant oxygen isotopes in the 2021 Fagradalsfjall eruption, Iceland. Nature Communications (2022).
2. Rapid shifting of a deep magmatic source at Fagradalsfjall volcano, Iceland. Nature (2022).
3. Melt inclusion constraints on petrogenesis of the 2014–2015 Holuhraun eruption, Iceland. Contributions to Mineralogy and Petrology (2018).
4. Quantifying lithological variability in the mantle. Earth and Planetary Science Letters (2014).