Temperature variations in the upwelling mantle plume below Iceland may have formed V-shaped ridges on the ocean floor and influenced the patterns of deep ocean currents, reports a paper published online this week in Nature Geoscience.

Nicky White and colleagues measured the geochemistry of rock samples taken from the V-shaped ridges of high topography on the sea bed near Iceland. They show that variations in rock geochemistry can best be explained by blobs of unusually hot mantle rising up in the underlying plume and spreading outwards radially.

The team also shows that variations in the temperature of the Iceland mantle plume over the past 7 million years could have driven episodic uplift of the sea floor that, in turn, moderated the ocean circulation patterns in the North Atlantic Ocean.