NASA has revealed that the Martian crater Gale, through which the NASA rover Curiosity is currently traversing, was covered with glaciers about 3,500 million years ago.

Very cold liquid water also flowed through its rivers and lakes on the lower-lying areas, forming landscapes similar to those which can be found in Iceland or Alaska. This is reflected in an analysis of the images taken by the spacecraft orbiting the red planet.

Ancient Mars held large quantities of water, yet its global hydro-geological cycles were very cold, so much so that they induced the presence of a giant ocean, partially ice-covered and rimmed by glaciers on the lower plains of the northern hemisphere

Now, an international team of researchers has confirmed this global picture locally, on the Martian site where Curiosity is roving: Gale crater. "This crater was covered by glaciers approximately 3,500 million years ago, which were particularly extensive on its central mound, Aeolis Mons" the lead investigator of the study Alberto Fairen, from the Centro de Astrobiología (INTA-CSIC) in Spain and Cornell University in the USA points out. "However, at that time there were also rivers and lakes with very cold liquid water in the lower-lying areas within the crater," adds the researcher, who highlights the fact that ancient Mars was capable of "maintaining large quantities of liquid water (an essential element for life) at the same time that giant ice sheets covered extensive regions of its surface".To carry out the study, the team has used images captured with the HiRISE and CTX cameras from NASA's Mars Reconnaissance Orbiter, together with the HRSC onboard the Mars Express probe managed by the European Space Agency (ESA).

Analyses of the photographs have revealed the presence of concave basins, lobated structures, remains of moraines and fan-shaped deposits which point to the existence of ancient glaciers on Gale. In fact they seem to be very similar to some glacial systems observed on present-day Earth. NASA's Mars Curiosity Rover recently completed a Martian year - 687 Earth days.