J. Geophys. Res. http://doi.org/ngz (2013)


Over the past century, the warming climate has caused glaciers in Iceland to retreat. Numerical simulations show that the decreased volume of ice at the surface has lowered pressures in the underlying mantle, causing mantle melt and the generation of large volumes of magma.

Peter Schmidt at Uppsala University, Sweden, and colleagues used a numerical model to analyse how the crust and mantle in Iceland have responded to melting glaciers since 1890. As the glaciers decreased in volume, not only did the Earth's surface rebound but the pressure in the crust and underlying mantle decreased. The melting temperature of mantle rocks is sensitive to pressure: under lower pressures, mantle rocks melt at lower temperatures. Decompression of the mantle beneath Iceland therefore caused increased melting of the Icelandic mantle.

The researchers estimate that glacially induced melting has generated an extra 0.21 to 0.23 km3 of magma each year beneath Iceland. The volume of magma predicted to eventually reach the surface in central Iceland would be sufficient to supply eruptions similar in size to the 2010 Eyjafjallajökull eruption once every seven years.