lecture 6: earth as a planet 1.the young earth 2.earth as a planet: interior 3.plate tectonics...
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Lecture 6: Earth as a Planet
1. The Young Earth2. Earth as a planet: interior3. Plate tectonics4. Atmosphere
News from Mars:
Opportunity Mars Rover at Santa Maria Crater - Feb. 2011
News from Mars:
The Formation of the Earth
• Precise timeline of early events.
The Planets
Earth as a planet - interior
Earth interior - seismic waves
Earth interior - seismic surface waves
Earth as a planet - plate tectonics
Plate tectonics
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Earth as a planet - plate tectonics
Earth as a planet - plate tectonics
Earth - plate collision & subduction
Kus
tow
ski e
t al .(
2006
)
Evidence from seismictomography for thesubduction of the plateunder Japan.
Variations in shear-wavevelocity, vS
Earth as a planet - plate tectonics
Earth as a planet - plate tectonics
Earth as a planet - tectonics
The Terrestrial Planets
Mercury Venus Earth Mars
Mars as a planet - interior
Earth
Mars as a planet - NO plate tectonics
Wyatt et al. [2004]; Data from Mars Odyssey THEMIS
basalt
dust
“altered basalt” (smectite, palagonite, zeolites)
Surface composition from thermal emission spectra
Mars as a planet - the surface
Earth as a planet - atmosphere
Main points to take home:
1) Hadean Earth (4 430 - 4 000 Myr): heavy bombardment epoch, outgassing, oceans
2) Earthquakes & seismic waves - interior map3) Earth’s interior is differentiated - iron core4) Plate tectonics - Earth’s crust is broken into
plates; mantle convective currents cause these plates to move
5) Atmosphere - Earth had 3 types of atmospheres, in terms of composition; today’s is mostly N2 (78%) and O2 (21%).