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Planetary Geology

Planet means _______________
Aug. 24, 2006, International Astronomical Union (IAU) formally defined a planet as:
1.
2.
3.

Exploration

Telescopic Observations
Human Exploration - Apollo 11, 12, 14, 15, 16, 17
Planetary Probes (excluding Earth orbiting)
Mercury: Mariner, Messenger
Lunar: Pioneer, Luna, Ranger, Surveyor, Lunar Orbiter, PFS, Hiten, Hagoromo, Clementine, Lunar Prospector
Mars: Mars, Zond, Mariner, Cosmos, Viking, Phobos, Mars Observer, Mars Global Surveyor, Mars Pathfinder, Nozomi, Mars Climate Orbiter, Mars Polar Lander, Mars Odyssey, Mars Express, Spirit, Opportunity
Asteroids: NEAR, Hayabusa, Deep Space 1
Outer Planets: Pioneer, Voyager, Galileo, Cassini
Comets: Giotto, Stardust, CONTOUR, Rosetta

Additional information can be found at the Planetary Geology - Exploration page.

Interior Structure

Differentiated interior: density layering

Core
Terrestrial:
Jovian:

Mantle
Terrestrial:
Jovian:

Crust
Terrestrial:
Jovian:

Atmosphere / Ocean
Terrestrial:
Jovian:

Internal Processes

Processes which create: igneous and metamorphic material; surface landforms
Tectonics and Plate Tectonics
Magmatism and Volcanism
Isostasy
Core and Mantle Convection
Differentiation

Tectonic Activity

Deformation and structural behavior of crustal material.
Heat from the core drives convection in the mantle.
Sources of Heat?
Mantle convection creates stress in the crust causing it to deform
Tectonic activity only occurs in planets with warm interiors.
Why?

Tectonic Stress

Stress is any force which acts to deform rocks.
Compression -
Tension -
Shear -

Volcanism

Heat from the core migrates towards the crust and causes mantle and crustal material to melt.
Molten or melted material is called ___________.

Volcanism

Magma is hot, therefore less dense than the surrounding material
What happens to the magma?
1)
2)
If the magma rises through the crust and reaches the surface:
1)
2)

External Processes

Processes which erode and shape surface.
Major Factors of Planetary Erosion
1)
2)
3)

Other Factors of Planetary Erosion

Atmospheric composition
Critical erosion factors on Earth:

Erosion

The mechanical and chemical destruction of the land (weathering) and the removal or transportation of material by flowing liquid (water), flowing or moving solids (ice, glaciers, impactors) or moving gas (wind).

Space Weathering

The alteration of the surface of small bodies unprotected by an atmosphere.
Iron nanoparticles are formed by the evaporation of minerals during micrometeorite impacts or exposure of the surface to the solar wind
Iron nanoparticles then condense onto nearby mineral surfaces
Importance of this process:

Impact Craters

Impact crater:

Small craters (simple craters) are <16 km diameter; smooth bowl- or cone-shaped interiors (some with flat bottoms) - exterior deposits slope away from rim

Large craters (complex craters and basins) - roughly circular, terraced rims with a central peak or ring peak, surrounded by hummocky debris; >16 km diameter

Impact Basins

The term applied to craters larger than 200 km is basin
Similar structure to large craters, but bigger
- roughly circular
- terraced rims with a central peak or ring peak
- surrounded by hummocky debris
- multi-ringed
- lava flows often fill the basin bottom

Cratering Process - Simple Craters

1)
2)
3)
4)
5)
6)

Cratering Process - Large Craters and Basins

1)
2)
3)
4)
5)
6)

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