Iceland Plume Discovery Reveals Ancient Volcanic Funnels Across North Atlantic

Sixty million years ago, a powerful plume of hot rock deep under Iceland triggered massive eruptions across the North Atlantic, from Greenland and Iceland to Scotland and Ireland. Cambridge scientists have discovered that hidden weak zones in Earth's plates acted like funnels, spreading the plume's heat and lava over a vast region. This breakthrough explains the far-flung volcanic fields of that time and reshapes how we view our planet's interior – influencing ancient landforms as well as modern earthquake patterns and even geothermal energy prospects.

The Anomaly Beneath the Ocean

According to the new study, the basalt pillars at Northern Ireland's Giant's Causeway are relics of that ancient volcanic episode. Researchers used seismic tomography to image Earth's crust. The images showed a band of unusually thin lithosphere beneath the Irish Sea, where ancient volcanoes align with this weak zone and Iceland's deep plume was funneled. This seismic “CT scan” revealed hidden plate structure: a corridor of thin, weak rock connecting the plume to distant eruptions.

Rewriting Earth's Volcanic History

Rather than invoking multiple plumes, the study suggests one Icelandic “hot spot” powered all these eruptions. (A mantle plume is essentially a rising column of hot rock from deep inside Earth.) The new data show that the plume's heat eroded and thinned the crust along hidden weak zones. In effect, one deep-source of heat can feed many volcanic centers through narrow plate “funnels,” overturning the old idea of a single fixed volcano source.

Even today, those hidden “funnels” still show their effect. Earthquakes in Britain and Ireland cluster along the plume's old paths. The same thinned crust traps extra deep-Earth heat. In short, the plume's scars still guide where the ground shakes and where geothermal energy may lie.