Mars Geology Dr Ganna Anya Portyankina September 2015

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 - shallowsided – 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 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

Gullies 26

Sediment layering 27