Important role of groundwater springs in shaping Mars   Iani Chaos on Mars, an area where Light Toned Deposits, or LTD, are known to be present. An analysis of data and images from Mars Express suggests that several LTD, some of the least understood structures on Mars, were formed when large amounts of groundwater burst on to the surface. Scientists propose that groundwater had a greater role in shaping the martian surface than previously believed, and may have sheltered primitive life forms as the planet started drying up. This image was obtained with the High Resolution Stereo Camera on board ESA’s Mars Express spacecraft.   Global map of Mars indicating areas that show LTD. An analysis of data and images from Mars Express suggests that several Light Toned Deposits, or LTD, some of the least understood structures on Mars, were formed when large amounts of groundwater burst on to the surface. Scientists propose that groundwater had a greater role in shaping the martian surface than previously believed, and may have sheltered primitive life forms as the planet started drying up. These deposits occur on a large scale in the Arabia Terra, Chaotic Terrain and Valles Marineris, close to the Tharsis volcanic bulge, on Mars.   Crommelin Crater on Mars, an area where Light Toned Deposits, or LTD, are known to be present. An analysis of data and images from Mars Express suggests that several LTD, some of the least understood structures on Mars, were formed when large amounts of groundwater burst on to the surface. Scientists propose that groundwater had a greater role in shaping the martian surface than previously believed, and may have sheltered primitive life forms as the planet started drying up. This is a mosaic composed of nadir images taken by the High Resolution Stereo Camera on board ESA’s Mars Express spacecraft.   Mars Express High Resolution Stereo Camera image of Hebes Chasma. Hebes Chasma is an enclosed trough, almost 8000 m deep, in Valles Marineris, the Grand Canyon of Mars, showing Light Toned Deposits. This is an area where water is believed to have flowed. An analysis of data and images from Mars Express suggests that several Light Toned Deposits, some of the least understood structures on Mars, were formed when large amounts of groundwater burst on to the surface. Scientists propose that groundwater had a greater role in shaping the martian surface than previously believed, and may have sheltered primitive life forms as the planet started drying up. Hebes Chasma is located at approximately 1° south and 282° east. Image data was obtained on 16 September 2005 with a ground resolution of approximately 15 m/pixel. Release date: 15 July 2009