The Geology of Mars Flight into Valles Marineris Geological Processes Chaotic Terrain Forms when subsurface water or ice causes a loss of support and the ground collapses. Graben A depressed block of land bordered by parallel faults (graben is German for ditch). Sapping Sapping valleys are formed breaks the surface and undermines rock and sediment, causing it to collapse. Slumping The grounds collapses and sinks or falls suddenly and heavily. Subsidence The sinking of ground surface due to the physical removal of ground surface. Landslides Material that has fallen down a steep slope and material piles up at the bottom. Layers Formed by stacks of lava flows, ash from volcanoes, dust, or by sediments deposited in water. Fractures/Faults Result from breaks in the surface. They are generally straight. Fracture Fault Gullies Often found on crater walls or other slopes. May be associated with past liquid water or areas once covered with snow. Fissures Cracks that are found sometimes on the sides of volcanoes. Lava flows may be seen moving away from the fissure, indicating lava flow. Lava Flows Formed by flowing lava. Flows can look “wavy” or “fingery.” Flows are raised features. Collapsed Lava Tube Look similar to channels. Lava once flowed underground through a tunnel. Some aren’t completely collapsed and look like a small chain of craters. Channels Formed by consistent flow of water over a long period of time. Has a curvy or meandering shape. Streamlined Islands Thought to be associated with the plast flow of water around a feature. Often found in outflow channels wher large amounts of water flowed. Sand Dunes Often seen in the bottom of craters or channels. Look like ripples of material. Yardangs Formed by sand-sized particles being blown against a surface, wearing it away. Regions of Mars Tharsis Volcanic Plateau on Mars. There are three enormous shield volcanoes Arsia Mons, Pavonis Mons, and Ascraeus Mons, which are known as the Tharsis Montes. Volcanic Plateau on Mars. Arsia Mons Parvonus Mons Volcanic Plateau on Mars. Ascraeus Mons Volcanic Plateau on Mars. Olympus Mons is nearby. There are other small volcanoes. Lava flows are common in the Tharsis region. Marineris Valles Marineris (the Grand Canyon of Mars is found in this area. On Earth, it would stretch from San Francisco, CA to New York, NY. There are many regions in Valles Marineris. There are plateaus in the south, craters in the north and south, additional valleys in the north Meridani A heavily cratered region. Opportunity found evidence for water in this region. The Aureum & Arsinoes Choases (chaotic terrain) are found in Meridani. Syrtis Major This is a plateau & volcanic region. You can see examples of wind blow terrain. This is a highly cratered region. Valleys and layering geology are found here. Hesperia The southern part of the region is on a plateau. It is a highly cratered region in the south. Elysium Planitia is a major volcanic region. Elysium Mons volcano found here. South and west from Elysium Mons you find Elysium Chasma. Continue south and west and you find the Hyblaeus Dorsa lava flows. Memnonia The southern part of the region has many craters. The craters in this region show evidence of erosion. Tartarus Montes In the northeastern corner there are two plains – Arcadia Planitia and Amazonus Planitia. An on-line atlas of Mars.