Scientists at The University of Manchester have uncovered the first evidence of seawater deep inside the Earth shedding new light on the fate of the planet's oceans, according to research published in Nature.

For years geologists have debated whether seawater is subducted (absorbed) into the deep Earth or whether there is a 'subduction barrier' blocking its absorption.  For the first time scientists at The University of Manchester have positively identified seawater in volcanic gas samples originating from the Earth's mantle - the region just below the crust and extending all the way down to the core - supporting the theory that seawater is subducted deep into the Earth and enabling them to test this theory further.

Professor Chris Ballentine and Dr Greg Holland of the University's School of Earth and Atmospheric and Environmental Sciences have also revealed that up to 10% of the Earth's oceans have been absorbed deep into the Earth since its formation.  Professor Ballentine said: "We can show that up to 10% of the Earth's oceans have been absorbed into the planet since formation. This accounts for about half of the water in the deep earth, the remainder of which was trapped when the Earth first formed. This work, for the first time, quantifies the 'geological water cycle'."