Ancient mantle plume created a 60-million-year volcanic trail from Iceland to Ireland

Lava plateaus, volcanic islands, and basalt columns litter the North Atlantic, yet they sit hundreds – even thousands – of miles apart. What tied them together?

For decades, geologists have puzzled over this geological jigsaw that stretches from Greenland’s coast to the cliffs of Northern Ireland.

Now a team of international researchers backed by the European Space Agency (ESA) has cracked the code, revealing how an ancient plume of super-hot mantle rock thinned Earth’s outer shell. That plume lit a chain of volcanoes whose fingerprints still shape the region today.

Mantle plume sparked ancient fire

Iceland’s frequent eruptions are just the modern flicker of a fire that first roared roughly 60 million years ago.

At that time, the upwelling now known as the Iceland Plume burst through the crust, unleashing the North Atlantic Igneous Province: a lava flood so vast it covered nearly a million square kilometers.

Such large igneous provinces are no ordinary eruptions – they can inject climate-altering gases into the atmosphere fast enough to spark mass extinctions.

Yet the ancient lava vents did not cluster neatly around Iceland. Instead, they popped up in Scotland’s Inner Hebrides, across Ireland’s Antrim Coast and along Greenland’s margins, leaving scientists to wonder how one plume could punch holes so far from its core.

The prevailing theory was that hot plume material flowed sideways beneath the plates, but direct proof was thin.

Satellites, gravity, and a 4-D puzzle

Enter ESA’s 4D Dynamic Earth project. By combining gravity anomalies measured by the GOCE satellite with seismic readings and surface geology, scientists have produced the sharpest picture yet of the lithosphere.

This stiff outer layer includes Earth’s crust and the uppermost mantle beneath Britain, Ireland, and the adjoining seafloor.

Gravity mapping acts like a CT scan: dense regions tug more strongly on the satellite, revealing hidden structures.

The new analysis showed bands of startlingly thin lithosphere that line up precisely with the 60-million-year-old volcanic centers.

“This striking correlation suggests that hot material from the Iceland Plume penetrated the region, eroding the lithosphere. The resulting combination of thin lithosphere, hot asthenosphere, and decompression melting likely triggered the uplift and volcanic activity,” said Sergei Lebedev from the University of Cambridge.

Where that shell thinned, melting surged and lava erupted – explaining why volcanoes sprouted far beyond Iceland itself. The findings, presented this spring at ESA’s Living Planet Symposium, turn a long-standing hypothesis into hard evidence.

Earthquakes mark ancient plume scars

These findings also explain a modern mystery. Although the British Isles lie far from an active plate boundary, small earthquakes cluster sporadically across the region.

The new map reveals those tremors occur where the lithosphere remains thinnest or where abrupt thickness contrasts create weak zones.

According to Raffaele Bonadio, another researcher at Cambridge, the plume left behind a lasting mechanical heterogeneity, a kind of geological scar that still influences where the crust creaks.

Eruptions altered ancient atmosphere

Large igneous provinces like the North Atlantic event are suspected climate saboteurs. Their eruptions can belch billions of tons of carbon dioxide, driving long-term warming. In contrast, sulfur aerosols can trigger brief volcanic winters.

Understanding how mantle plumes breach the surface helps scientists reconstruct ancient climate swings – a vital reality check for models that project our own greenhouse future.

NGGM, ESA’s forthcoming Next Generation Gravity Mission, aims to sharpen that understanding.

As ESA geodesist Ilias Daras explains, the twin-satellite mission will “track mass changes on the planet’s surface and deep within its interior,” offering a fresh lens on tectonics, ice-sheet dynamics and mantle convection.

Mantle plumes trigger lasting stress

The new research underscores that Earth’s interior is no inert foundation. Hidden upwellings can thin the crust, alter stress patterns, and leave behind zones prone to quakes long after the last lava cools.

For hazard planners in Britain, Ireland, and Iceland, the map provides a novel template for assessing risk. For petrochemical explorers, it hints at where heat and fractures might have cooked hydrocarbons.

Meanwhile, tourists on the Antrim coast can marvel at the Giant’s Causeway’s hexagonal pillars with fresh awe. Those stones are chapters in a 60-million-year saga authored by a plume that rose from nearly 3,000 kilometers below.

Looking deeper beneath Earth

Earth’s mantle plumes will continue to shape the planet, but satellites give humans an ever-clearer seat in the theatre. GOCE’s data, gathered in digital archives, remains a treasure trove.

NGGM promises finer resolution. Paired with seismic arrays and ocean-bottom instruments, future studies could reveal whether other broad provinces – such as those underlying the Deccan Traps of India or the Pacific’s oceanic plateaus – share the same thin-lithosphere signature.

For now, the North Atlantic story offers a reminder: the ground beneath our feet records not just the slow march of drifting continents but dramatic pulses that can rewrite climate and life. Understanding those pulses begins with looking down – then looking deeper.

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