[kach22i]

http://www.nature.com/nature/journal/v435/n7043/full/435723b.html

This image from the Mars Express spacecraft shows a pocket of water ice nestling in a martian crater, bathed in the late martian summer sun.

The shadow of the crater's rim, which towers 300 metres over the surrounding plains, prevents the ice from vaporizing in the planet's thin atmosphere. A dusting of frost survives inside the rim to the upper right, while the sun glimmers on its south-facing outer edge.

The 35-kilometre-wide crater sits 70° north of the martian equator, in a low-lying region known as Vastitas Borealis. Previous orbiters have spotted ice deposits in craters, but the High Resolution Stereo Camera on board the European probe is the first to return a three-dimensional colour image of an icy spot. The ice may be up to 200 metres thick, and lies over a dune field that has formed in the sediment on the crater's floor. The data were collected on 2 February, and this image was created for Nature last week.

At the bottom of the link it says: Mars may have a frozen sea........................but you need to subscribe.