Glacial erosion increased volcanic eruptions at ice age-end

The combination of erosion and melting ice caps led to a massive increase in volcanic activity at the end of the last ice age, says a new study.

As the climate warmed, the ice caps melted, decreasing the pressure on the Earth's mantle, leading to an increase in both magma production and volcanic eruptions.

The researchers, led by the University of Cambridge, found that erosion also played a major role in the process, and may have contributed to an increase in atmospheric carbon dioxide levels.

"It has been established that melting ice caps and volcanic activity are linked -- but what we have found is that erosion also plays a key role in the cycle," said lead author Pietro Sternai of Cambridge's Department of Earth Sciences.

"Previous attempts to model the huge increase in atmospheric CO2 at the end of the last ice age failed to account for the role of erosion, meaning that CO2 levels may have been seriously underestimated," Sternai noted.

Over the past million years, the Earth has gone back and forth between ice ages, or glacial periods, and interglacial periods, with each period lasting for roughly 100,000 years.

During the interglacial periods, such as the one we live in today, volcanic activity is much higher, as the lack of pressure provided by the ice caps means that volcanoes are freer to erupt.

But in the transition from an ice age to an interglacial period, the rates of erosion also increase, especially in mountain ranges where volcanoes tend to cluster, the researchers pointed out.

Using numerical simulations, which modelled various different features such as ice caps and glacial erosion rates, the researchers found that erosion is just as important as melting ice in driving the increase in magma production and subsequent volcanic activity.

The results were published in the journal Geophysical Research Letters.