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GEOL3045: Planetary Geology. Lysa Chizmadia Earth-Moon System. Earth is 3rd planet from the Sun First with natural satellite Largest planet in inner solar system Diameter = 1.3 x 10 4 km Highest density 5.52 g/cm 3 FeNi core 1/6 ’s volume > Mars Youngest surface Weathering
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GEOL3045: Planetary Geology Lysa Chizmadia Earth-Moon System
Earth is 3rd planet from the Sun First with natural satellite Largest planet in inner solar system Diameter = 1.3 x 104 km Highest density 5.52 g/cm3 FeNi core 1/6 ’s volume > Mars Youngest surface Weathering Plate Tectonics Introduction Image from: http://www.nineplanets.org/earth.html 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
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 • Atmospheric Layers • Water Cycle • Both act to weather surface • Surface is Young! Image from:http://www.solcomhouse.com/atmosphere.htm
Weathering • Mechanical Weathering • Physical breakdown of rocks into smaller pieces • Chemical Weathering • Chemical reactions which act to dissolve minerals into aqueous ions • Presence of water near triple point Image from: http://www.sv.vt.edu/classes/MSE2094_NoteBook/96ClassProj/examples/triple.html 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) • 29.7 days • Density = 3.35 g/cm3 • Due to size & composition, considered a terrestrial planet • Surface Composition • Bright Highlands (82%) • CaAl2Si2O8 • Dark Maria (18%) • Basalt Image from: http://www.solarviews.com/eng/earth.htm Near Side Far Side Images from: http://en.wikipedia.org/wiki/Moon
Tides • Spring tide: when Earth, Moon & Sun aligned • Neap tide: Moon perpendicular to Sun
Earth Plate Tectonics Divergent Plates Convergent Plates Transform Plates Hot Spots Complex Atmosphere Hydrosphere => Weathering => Young surface Surface composition Oceans = Basalt Continents = Granite Moon (Luna) 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 Summary