The eastern Sahara Desert was once home to a 45,000 km2 freshwater lake similar in surface area to the largest in the world today.
A study led by the University of Exeter has revealed that the mega lake was probably formed more than one hundred thousand years ago in the White Nile River Valley in Sudan.
Dr Tim Barrows of the University of Exeter and colleagues used a dating approach based on exposure to cosmic rays to measure the amount of the isotope beryllium-10 in shoreline deposits. Its abundance can be used to calculate how long rocks or sediments have been exposed at the surface of the earth. (more…)