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? 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% 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

Hypsometric Curve:

“Plate” Tectonics

“Plate” Tectonics

“Plate” Tectonics

“Plate” Tectonics

“Plate” Tectonics

“Plate” Tectonics ? ?

Geologic “Action” mostly happens at plate boundaries (Earthquakes, Volcanoes, Mountain Building, etc.)

“World’s Geologic Wonders:” Example/ Erta Ale Volcano, Ethiopia Aerial view of Erta Ale summit caldera from S during February 2002 overflight. The active pit crater is in the center of the picture.

Erta Ale, 2011 (used in “Clash of the Titans”)

Erta Ale

Erta Ale, fountaining

Erta Ale, pseudo-subduction zone

Erta Ale, looking like mid-ocean ridges

Erta Ale, looking like Mid-Atlantic ridge, with transforms too!:

Erta Ale

Erta Ale, looking like a plate boundary triple-junction

Erta Ale, 2010 flow Extent of Nov. 2010 lava flows viewed from SW of crater on rim

Dallol hot springs, Ethiopia

Dallol hot springs, Ethiopia

Dallol hot springs, Ethiopia

Nyiragongo, DR Congo

Nyiragongo

Pu’o O’o, Hawaii

Marum crater, Ambrym island, Vanuatu

Mt. Erebus Lava Lake, Antarctica

Earliest Earth?

Rifting:

Rifting:

Rifting:

Subduction:

Subduction:

Mountain Building:

Mountain Building:

Transform Faulting:

There are other geodynamic processes besides plate tectonics What causes the volcanism at Hawaii?

Hot Spot Mantle Plume Volcanism

Map of Ocean Bathymetry (how do we get this?)