New Scientist       

Volcano hunters dig into the Sahara’s watery past

By Sandrine Ceurstemont

The Sahara desert wasn’t always a sea of sand: it could once have been a green corridor that early humans trekked through on their way to Europe. Earlier this year, Stefan Kröpelin from the University of Cologne, Germany, and his team made a pioneering expedition to the Tibesti mountains in northern Chad to look for clues to the region’s past climate. They headed for its highest volcanic peaks since their craters trap ancient sediments and so act as natural time capsules. The crater on Emi Koussi – the desert’s highest peak – had never been sampled before. These photos track the team’s journey through an area plagued by political instability, as they uncover a picture of its past landscape.

 Read more ...