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Main Points: Geodynamics Earth is a system of systems ( “ spheres ” ) Earth ’ s layering is driven by gravity Pressure and temperature increase with depth #3 causes some strange conflicts in material behavior
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Main Points: Geodynamics • Earth is a system of systems (“spheres”) • Earth’s layering is driven by gravity • Pressure and temperature increase with depth • #3 causes some strange conflicts in material behavior • Heat within Earth flows by conduction, convection, and radiation; differently within different layers • Earth’s internal motions are driven by the 2nd law of thermodynamics (heat flows from hot to cold regions)
Question: What percentage of the volume of Earth’s crustal rock is made up of oxygen? a) 0.94% b) 4.9% c) 9.4% d) 49% e) 94% Tweet to: @wueps201 <letter> 752
Geosphere Composition of Crust (%): Weight Moles Volume Oxygen 47.2 61.7 93.8 Silicon 28.2 21.0 0.9 Aluminum 8.2 6.4 0.5 Iron 5.1 1.9 0.4 Composition of Whole Earth (weight %): Iron 35 Oxygen 30 Silicon 15 Magnesium 13 Nickel 2.4
Hydrosphere: 96.5% in Oceans 3.5% in glaciers, groundwater ~0% in streams, lakes, atmosphere, biosphere 71% of Earth’s surface is currently covered with water. If Earth were a perfect sphere, it would be covered with 2.25 km of water.
Atmosphere: Composition (by volume): N2 - 78.1% O2 - 20.9% Ar - 0.93% H2O - 0.1% CO2 - 0.040% (increasing) Ne - 0.0018%
Earth's magnetic field LOOKS LIKE there is a tilted, offset, wandering, bar magnet in its core. (But there isn’t!!) Fluid flow (convection) of liquid iron in Earth’s outer core creates the magnetic field. Magnetohydrogeodynamo
The magnetosphere protects us from ionized particles of solar wind.
Biosphere: Extends from the seafloor and deep crust, to the tops of mountains and the atmosphere. 3 - 300 million species; ~1.5 million identified VERY significant geological agent (Ex: atmosphere, weathering)
Temperature 10ºC ? ? ? 1 bar Pressure
Temperature 10ºC ~3500ºC ~5500ºC 3.62 Megabars 1 bar Pressure
A Planet’s History is Dominated by the Flow of Heat Outward: Occurs through Radiation Conduction Convection
Major “players” in the story of Earth’s evolution: (1) 1st Law of Geology: Rocks Fall Downhill (Gravity) - Controls LAYERING, MINERAL PHASES
Major “players” in the story of Earth’s evolution: (2) 1st Law of Geophysics - Heat “rises” (Thermodynamics, thermal expansion, gravity) Heat flows from hot regions to cold regions (therefore up and out of the Earth). (1) 1st Law of Geology: Rocks Fall Downhill (Gravity) - Controls LAYERING, MINERAL PHASES
Geologic “Action” mostly happens at plate boundaries (Earthquakes, Volcanoes, Mountain Building, etc.)
“World’s Geologic Wonders:” Example/ Erta Ale Volcano, Ethiopia
Erta Ale, looking like Mid-Atlantic ridge, with transforms too!:
