Clays in Pacific lavas back drier early Mars

A study of rocks at an old A-bomb test site in the Pacific has led a team of scientists to conclude that early Mars was not so warm and wet, as many argue.

The rocks at Mururoa Atoll in French Polynesia contain clay minerals that look like those seen on the Red Planet.

But whereas the Martian clays are taken to be the products of weathering of rocks by liquid water, the atoll's clays have a very different origin.

These were precipitated directly from water-rich molten rock as it cooled.

http://www.bbc.co.uk/news/science-environment-19525421