The Dynamic Earth

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The Dynamic Earth
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Earths Internal Zones- CORE

• 1/2 radius
• 2 parts
• 16 volume, but 31 of mass
• inner core - solid, mostly iron, 3400oC
  3,000,000Gs gravity
• outer core - liquid, 3700-4300oC

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Earths Internal Zones- MANTLE

• Solid
• 10-2900km from surface
• 82 of volume, but 68 of mass
• Fe, plus O, Si, Mg

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Earths Internal Zones- MANTLE

• Low velocity zone
• upper part of mantle
• semi-liquid (1-10)
• seismic waves slow down
• asthenosphere

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Earths Internal Zones- CRUST

• Thinnest section
• 2 volume, 1 mass
• 10-65km thick
• Earthquakes are generated
• Plate movement
• Lithosphere

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Composition of Earths Crust
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So to summarize

• Inner core Fe
• Outer core liquid Fe and Ni
• Mantle Fe, plus O, Si, Mg
• Crust O, Si, and other elements

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Types of Crust Oceanic

• 71 of surface, dense, 10km thick
• OCEANIC RIDGE SYSTEM
• 80,000km long
• 1500-2500km wide
• 2-3km wide
• Abyssal Floor
• Deep ocean basins, 5km below sea level
• Trenches
• 8km below sea level

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Abyssal Sea Floor Trenches
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Continental Crust
Oceanic Ridge System Continental Shelf

• Higher and thicker than oceanic crust
• Averages 35km thick
• Lower density so they float
• Continental Shelf - underwater portion of the
  continental crust

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Crustal Plates

• 100km thick (crust and mantle) - lithosphere
• Move over the semi-liquid asthenosphere
• Silly-putty
  consistency
• Move at finger
  nail growth rate
  (1 inch/year)

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Plate Tectonics Theory

• Explains movement of Earths plates and processes
  that occur at boundaries
• The movement of the plates
• is an explanation for the biogeography of
  organisms
• is responsible for the
  earth surface features
• concentration of
  minerals

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Plate Tectonics-Evidence

• (Biogeography)
• Glacial Deposits
• Unique rock types on neighboring plates
• Shape of continents
• Continued activity at boundaries
• Sat3llite Measurement of spreading

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Evidence Shape of Continents
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Evidence Unique Rock Types
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Volcano Earthquake Distribution
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Glacial Rock Distribution
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BiogeographyFossil Evidence
Distribution of Animal and Plant species
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Plate Boundaries
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Divergent Boundaries

• Plates move in opposite directions
• Ocean spreading
• Creates ridge
• Youngest area of
  ocean
• Earthquakes
• and volcanoes

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Continental to Continental Divergence
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Convergent Boundaries

• Plates move toward each other
• Oceanic plate is subducted under continental
  plate
• Subduction zone
  makes a trench
• Earthquakes and
  volcanoes
• Oldest part of
  ocean

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Oceanic to Oceanic Convergence
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Continental to Continental Convergence
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Oceanic to Continental Convergence
Why does the oceanic plate go under the
continental one?
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Transform Fault

• Plates move in opposite, parallel directions
• San Andreas
• Earthquakes
  
• No volcanoes

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San Andreas Fault
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External Processes Erosion

• Material is broken down, worn away, and moved
• Streams are primary source
• Also wind and gravity

Dont forget about erosion! Its really
important for the whole class!
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External Processes Weathering

• Mechanical
• A large rock is broken down into smaller rocks
  (frost wedging)
• Chemical
• A rock is
  decomposed by
  chemical reactions
• oxidation,
  acid rain,
  hydration

A weathered statue in Copenhagen, Denmark
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External Processes Mass Wasting

• Large amounts of material are carried downhill by
  gravity

A rock slide in Bryce Canyon, Utah closed down
part of the canyon
Rock Slides
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External Processes Glaciers

• Solid, dense ice
• Moves downhill, carving as it goes
• Carries material (leaves moraines)

Moraines in Bylot Island, Canada
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Rocks and Minerals

• ROCKS
• Natural combinations of one or more minerals.
• MINERALS
• Inorganic solids found in nature.
• Rock-forming minerals are divided into several
  groups

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IGNEOUS ROCKS

• Rocks formed by molten rock (magma)
• made at plate boundaries
• Below surface
• crystals, gem stones
• granite (continental)
• basalt (ocean floor)

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IGNEOUS ROCKS

• Above surface
• lava, no crystals
• obsidian, pumice

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Sedimentary

• Rocks formed from sediments, other rocks
• Small rocks carried by water
• sandstone/shale

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Sedimentary

• Compaction of dead animals limestone
• Decomposition of plants coal
• 3/4 of Earths surface sedimentary
  rock

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Metamorphic

• Formed when a pre-existing rock is subjected to
  extreme heat, chemicals and/or pressure

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• Higher-numbered minerals
• scratch
• Lower-numbered minerals

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Mineral Resources

• Naturally occurring in or on the crust
• Can be extracted and converted into useful
  materials
• Nonrenewable because of slowness of rock cycle
• Energy resources coal, oil, uranium
• Metallic resources iron, copper
• Nonmetallic salt, clay, water, sand

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Identified Mineral Resources

• Known location and quantity

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Undiscovered Mineral Resources

• Believed to exist, but location unknown

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Reserve Mineral Resources

• Identified resources that can be extracted
  economically

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Other Mineral Resources

• Identified, but not economical
• May become reserves

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Human Impacts

• Clearing land and vegetation
• Over grazing
• Mining
• Off-road
  vehicles