Paris, Oct 17 : The High Resolution Stereo Camera (HRSC) on board the European Space Agency’s Mars Express orbiter has obtained pictures of the Noachis Terra region on the Red Planet, in particular, the striking Maunder crater.

The images were taken in orbits 2412 and 2467 on November 29 and December 14, with a ground resolution of approximately 15 metres per pixel.

The impact crater, named after British astronomer Edward W. Maunder, lies 50 degrees South and two degrees East, approximately in the centre of Noachis Terra.

It is located halfway between Argyre Planitia and Hellas Planitia on the southern Highlands of Mars.

The crater has a diameter of 90 kilometres and a depth of 900 metres, but used to be much deeper earlier.

Agency astronomers said the west of the crater experienced a major slope failure, during which a large landslide transported loose material eastward, to the inner parts of the crater. It has since been filled partially with large amounts of material.

They said the edges of the crater rim that collapsed, now showed gullies, which might be associated with the mass transport of the material.

They said the transition zone from the western rim of the crater to the rather smooth crater floor on the eastern edge showed hummocky terrain, littered with irregularly shaped hills and valleys, which were formed by the deposition of landslide debris.

The pictures showed the crater floor in the east to be bounded by a trough approximately 700 metres deep, they said.

Astronomers now speculate the trough to be possibly associated with a landslide on the western edge of the crater.

Some gullies are also seen on the upper edge of the trough, which is possible evidence for water seepage, the ESA said in a release.

The scientists said the small, 500 to 2500-metre long, dark features on the crater floor are 'eye-catching'.

These features, called Barchan dunes, are one of the most abundant dune forms in arid environments. Dunes of this kind are also found on Earth, for example in the West-African Namib Desert, the researchers said.

The agency said the colour scenes were derived from the three HRSC-colour channels and the nadir channels. The perspective views were calculated from the digital terrain model derived from the HRSC stereo channels, and the anaglyph image was calculated from the nadir channels and two stereo channels, stereoscopic glasses required for viewing.

The 3-D (anaglyph) picture was been put together from several individual 3-D images of different scenes, enhancing the view over larger areas, the statement said. (ANI)