An impact basin deep enough to swallow Mount Everest and surprising slopes in Valles Marineris highlight a global map of Mars that will influence scientific understanding of the red planet for years.

The map was generated from data acquired by the Mars Orbiter Laser Altimeter (MOLA), an instrument aboard NASA's Mars Global Surveyor. The high-resolution map represents 27 million elevation measurements gathered in 1998 and 1999.

The massive Hellas impact basin in the Southern Hemisphere is a striking feature of the map. Nearly nine kilometers (six miles) deep and 2,100 kilometers (1,300 miles) across, the basin is surrounded by a ring of material that rises about two kilometers (1.25 miles) above the surroundings and stretches out to 4,000 kilometers (2,500 miles) from the basin center.

The new data also show that the eastern part of the vast Valles Marineris canyon slopes away from nearby outflow channels, with part of it lying a half-mile (about one kilometer) below the level of the outflow channels.

The amount of water on Mars can be estimated using the new data about the south polar cap and information about the North Pole released last year. While the poles appear very different from each other visually, they show a striking similarity in elevation profiles. Based on recent understanding of the North Pole, this suggests that the South Pole has a significant water ice component, in addition to carbon dioxide ice.

For more information:
NASA/JPL Press Release
New MOLA Images
High Resolution MOLA Images