Deformities

The Tharsis Bulge is near the equator and measures 4,000 km across and 10 km high at the center. What caused this deformation is unknown. It may have been formed by an upward doming of the crust, or it might be an accumulation of volcanic materials. We know for certain that it was formed early on in Martian history as all of the lava flows are consistent with the present topography. Radiating from the bulge are numerous fractures that vary in intensity and age, so they are very important in determining the planet's history. Because of this, the Tharsis Bulge plays an important part in discovering the evolution of Mars.

Canals and Channels

East of Tharsis and south of the equator lies a system of canyons known as the Valles Marineris. It begins at the summit of the Tharsis bulge and extend 4,000 km eastwards into chaotic terrain. Depths range from 2 km to over 7 km where three canyons merge and form a 600 km chasm. In some parts of the canyons there is layered sediments. They might have formed under water, so many geologists believe that standing bodies of water partly filled these canyons in the past, though they might have also been created by seasonal changes in the Martian climate. It is also believed that flows created these channels, strong ones that may have been up to 10,000 times the average discharge rate of the Mississippi River. Impact craters are scarce within the Valles Marineris, probably because of erosion and deposition by landslides and wind. There are thousands of outflow channels that connect with the Valles Marineris that can be 100 km wide and 2000 km long that make up the chaotic terrain. They were probably formed by floods of water released from large groundwater reservoirs. As the water flowed across the land, it would simultaneously freeze and evaporate.