Mars Geology Dr. Ganna (Anya) Portyankina September, 2015 1 2 General information about Mars 3 4 5 6 7 8 All terrestrial planets have craters vv 9 Craters form when asteroids or comets crash into the surface of a planet. Impacts carve out a depression Material blasted away from the impact site is called ejecta 10 Craters give us information about the target surface and impactor (sizes, composition, material strength) surface age or the time since the surface formed 11 Geological record I: craters 12 13 New crater with ice 14 15 16 Volcanism Molten rock (magma) inside a planet is released at the surface Why does it rise? It is less dense than solid rock It is squeezed upward It contains gases (that expand) Three types, distinguished by viscosity of eruptions: Stratovolcanoes - steep-sided Shield volcanoes - shallow- sided Lava plains - flat, runny flows 17 Geological record II: volcanoes 18 Olympus Mons 19 Tectonics Tectonics refers to deformation of the lithosphere This can include stretching, compressing, bending, and cracking Most tectonics results from mantle convection Earth has plate tectonics, as it has an ocean and hence 2 types of crust 20 Geological record III: tectonics 21 Valles Marineris 22 Erosion Erosion is the breakdown or transport of surface material by liquid, ice, atmosphere / wind, or even other rocks 23 Geological record IV: erosion 24 Geological record IV: erosion 25 26 Gullies 27 Sediment layering