Pulses of hot mantle material upwelling in a mantle plume beneath Iceland caused uplift of the North Atlantic sea bed, reports a study published online this week in Nature Geoscience. The sea floor was temporarily lifted above sea level around 56 million years ago, allowing rivers to erode and create channels, before subsiding back beneath the ocean.

Ross Hartley and colleagues used seismic data to image the ancient landscape, which is located west of the Orkney-Shetland Islands and is today buried beneath two kilometres of sedimentary rock. Modelling of the topographic profiles along individual rivers in the reconstructed landscape shows that the surface was lifted up in a series of discrete steps, probably owing to episodic increases in the temperature of the mantle material rising up in the plume below.

In an accompanying News and Views article, Philip Allen says: “Hartley et al. demonstrate an intriguing connection between the ascent and lateral spreading of pulses of hot material in the Iceland mantle plume and patterns of uplift of the North Atlantic Ocean floor.”