Transcript GEOL3045: Planetary Geology

GEOL3045: Planetary Geology
Lysa Chizmadia
Earth-Moon System
Introduction
 Earth is 3rd planet from
the Sun
 First with natural satellite
 Largest planet in inner
solar system
Image from: http://www.nineplanets.org/earth.html
 Diameter = 1.3 x 104 km
 Highest density
 5.52 g/cm3
 FeNi core 1/6 ’s volume
 > Mars
 Youngest surface
 Weathering
 Plate Tectonics
Image from: http://en.wikipedia.org/wiki/Earth
Plate Tectonics
 Three types of plate
boundaries
 Divergent
 Convergent
 Transform
 Explains distribution of
e-quakes & volcanoes
 Driven by convection
 Primordial heat from
 Accretion
 Radioactive decay
 Core crystallization
Image from: http://en.wikipedia.org/wiki/Earth
Image from: http://www.nineplanets.org/earth.html
Divergent Boundaries
 AKA
Spreading
Center
 AKA Rifts
 Largest
Mountain
Chains in Solar
System
 Plates move
apart due to
eruption of lava
 New lava =
new oceanic
crust
Continental Rifting
Convergent Boundaries
 AKA Destructive Boundaries
 AKA Subduction Zones
 Old oceanic crust dense &
heavy
 Heavy vs. light => subduction
 Three Types:
 Ocean-ocean
 Ocean-continent
 Continent-continent
Transform Boundaries
 AKA
Conservative Plate
Boundary
 Plates slide past
each other
 Fracture zones in
Mid-ocean ridges
 Strike-slips faults
 Only e-quakes
 No volcanoes
Hot Spots
 Caused by
mantle plumes
 Plumes do not
move, plates do
 Leaves track of
ocean islands
 Bend at 40Ma
 Major change in
plate motion
Atmosphere & Hydrosphere
Image from: http://www.nineplanets.org/earth.html
Image
from:http://www.solcomhouse.com/atmosphere.htm
 Atmospheric Layers
 Water Cycle
 Both act to weather
surface
 Surface is Young!
Weathering
 Mechanical Weathering
 Physical breakdown of
rocks into smaller pieces
 Chemical Weathering
Image from:
http://www.sv.vt.edu/classes/MSE2094_NoteBook/96ClassProj/
examples/triple.html
 Chemical reactions
which act to dissolve
minerals into aqueous
ions
 Presence of water near
triple point
Image from: http://www.lsbu.ac.uk/water/phase.html
The Moon
 Distance from 
 3.8 x 105 km
 Orbit around 
 27.3 days (tidally locked)
 Rotation (phases)
Image from: http://www.solarviews.com/eng/earth.htm
 29.7 days
 Density = 3.35 g/cm3
 Due to size & composition,
considered a terrestrial planet
 Surface Composition
 Bright Highlands (82%)
Near Side
Far Side
Images from: http://en.wikipedia.org/wiki/Moon
 CaAl2Si2O8
 Dark Maria (18%)
 Basalt
Tides
 Spring tide: when Earth, Moon & Sun
aligned
 Neap tide: Moon perpendicular to Sun
Summary
 Moon (Luna)
 Earth
 Plate Tectonics




Divergent Plates
Convergent Plates
Transform Plates
Hot Spots
 Complex Atmosphere
 Hydrosphere
 => Weathering
 => Young surface
 Surface composition
 Oceans = Basalt
 Continents = Granite
 Terrestrial Planet
 B/c size & composition
 Low Density
 Little or no FeNi core
 Tidally locked to Earth
 Always see same side
 Pulls on oceans & crust
 Surface composition
 Anorthosite
 Basalt
 Old Surface
 Heavily cratered
 No weathering