Were we to see the same kinds of weathered rock on Mars, it's a good guess that life was once present on the Mars surface.

CNN: Curiosity opening Martian frontier?

The earlier loss of carbon dioxide will occur because as the climate gets hotter and wetter, more rock is weathered by rain.

BBC: Date set for desert Earth

Mr Rushden said engineers had found that the rocks around the hole left on the rock face were weathered and the area was being assessed and stabilised on Thursday.

BBC: Rock fall closes Jiggers Bank in Shropshire

The sand is very probably just the product of weathered basalt, the ubiquitous volcanic rock on Mars' surface.

BBC: Nasa's Curiosity Mars rover to scoop sand sample

Twelve-year-old Jordan Rock(ph) thinks cemeteries are creepy, but he walked anyway among the weathered, above-ground crypts in one of New Orleans' oldest cemeteries.

NPR: Searching for Roots at Genealogy Day Camp