Earth Systems

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Earth Systems
2
Earths Layers
Magma slowly circulates in convection cells
Liquid
Core nickel and iron
Made up of plates
solid
Semi-molten rock (flexible)
http//www.english-online.at/science/geologic-hist
ory-of-the-earth/geologic-eras-of-the-earths-histo
ry.htm
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Theory of Plate Tectonics

• Alfred Wegener Pangaea
• Plate Tectonics
• a. earths lithosphere is divided into plates,
  most of
• which are in constant motion
• b. continental and oceanic plates
• - movement driven by convection cells

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• Plate Boundaries
• a. Divergent
• - beneath the oceans
• - seafloor spreading (brings up important
  elements)
• b. Convergent
• - plates collide
• - subduction (responsible for the Andes
  in SA)
• - mountain formation (Himalayas in Asia)
• c. Transform Fault
• - plates slide past each other
• - San Andreas Fault

5

• Consequences of Plate Movement
• a. Earthquakes
• - occurs when rocks of the lithosphere
  rupture
• unexpectedly along a fault
• - fault zones/seismic activity
• - Richter Scale
• measurement of ground movement
• increases by a factor of 10

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• b. volcano
• - occurs as a plate moves over a hot spot
  and heat
• from the mantle melts the crust
• - as plate moves past the hot spot,
  leaves behind a
• trail of extinct volcanic islands (The
  Hawaiian
• Islands)

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Rock Cycle

• constant formation and destruction of rock
• Slowest of all Earths cycles
• Rock composed of one or more minerals
• Mineral solid chemical substance with uniform
• composition

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• 3 types of rocks
• a. Igneous
• b. Sedimentary
• c. Metamorphic

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• Igneous Rocks
• a. form directly from magma
• b. basaltic vs. granitic
• c. intrusive vs. extrusive

http//geology.com/rocks/igneous-rocks.shtml
http//earth.usc.edu/slund/systems/topic7.html
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• Sedimentary Rocks
• a. form from sediments being compressed by
  other
• overlying sediments
• b. typically uniform in composition
• c. sink for phosphorus
• d. fossil record

http//saturniancosmology.org/files/geology/sect2_
1a.html
11

• Metamorphic Rocks
• a. formed when rocks are exposed to extreme
• temperature and pressures
• ex) collision of tectonic plates
• b. structurally strong rocks

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Weathering and erosion

• Weathering
• a. occurs when rock is exposed to air, water,
• chemical compounds, animals, etc.
• b. 2 types
• - physical
• mechanical breakdown of rocks
• water, wind, burrowing animals

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• - chemical
• breakdown by chemical reactions
• acid deposition (acid rain)
• ? S emitted into atmosphere, combines
  with O2
• and forms SO2, SO2 reacts with water
  vapor to
• form sulfuric acid
• ? rapid degradation of gravestones,
  marble,
• limestone

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• Erosion
• a. physical removal of rock from a landscape
  or
• ecosystem
• b. wind, water, animals
• c. deposition
• d. acceleration of erosion
• - deforestation, overgrazing, road
  building

15
Soil

• Benefits of soil
• a. plant growth
• b. primary filter of water
• c. provides habitat
• d. filters chemical compounds deposited by air
  
• pollution

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• Soil Formation
• a. result of physical and chemical weathering
  of
• rocks and gradual accumulation of
  detritus from
• the biosphere
• b. mix of mineral and organic components
• c. 5 factors
• - parent material
• - climate
• - topography
• - organisms
• - time

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• Soil Horizons

E Horizon zone of leaching in acidic soils
(found below O)
Organic material in various stages of
decomposition
topsoil zone of organic material and minerals
mixed together
subsoil zone of nutrients
Least weathered layer similar to parent material
http//en.wikipedia.org/wiki/Soil_horizon
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• Soil Properties
• a. physical
• - texture
• determined by percentage of sand,
  silt, and clay
• ex) 40 sand, 40 silt, 20 clay -
  __________
• 70 sand, 20 silt, 10 clay
  - __________

http//www.soilsensor.com/images/soiltriangle_larg
e.jpg
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• porosity
• ? determines water holding capacity of soil
• ? depends on texture

http//www.eoearth.org/view/article/149751/
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• b. chemical
• - CEC
• cation exchange capacity
• nutrient holding capacity
• depends on amount of clay particles
  present
• - base saturation
• soil bases to acids
• bases (neutralizers) ? Ca, K, Mg, Na
• acids (detrimental) ? Al, H

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• c. biological
• - fungi, bacteria, protozoans
• - fix nitrogen (essential for plant growth)

http//urbanext.illinois.edu/soil/SoilBiology/imag
es/A-3.jpg
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• Soil Degradation
• a. loss of ability of soil to support plant
  growth
• b. due to overuse of land
• c. one major cause soil erosion (topsoil
  disturbed)

http//www.landfood.ubc.ca/soil200/soil_mgmt/soil_
degradation.htm
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Mineral Resources

• Ores concentrated accumulation of minerals from
  
• which economically valuable
  materials can
• be extracted
• - characterized by presence of
  valuable metals
• Metals elements with properties that allow them
  to
• conduct electricity and heat
  energy and
• perform other functions
• Reserve known quantity of a resource that can
  be
• economically recovered

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• Mining
• a. extracting mineral resources
• b. Types of mining
• 1. strip mining
• - removal of strips of soil and
  rock to expose ore
• - coal and sand
• - return tailing or spoils back to
  hole
• 2. open-pit mining
• - creating of large hole visible from
  Earths surface
• - copper mines

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• 3. mountaintop removal
• - remove entire top of mountain with
  explosives
• - deposits tailings in lower elevation
• 4. placer mining
• - use of river water to separate
  heavier items
• - example diamonds, gold
• 5. subsurface mining
• - below earths surface
• - coal, diamonds, and goal

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• Mining Safety
• - produces tailings which contaminate land and
  
• water with acids and metals
• - subsurface mining
• acid mine drainage
• accidental burial
• inhalation of gases and particles (black
  lung disease)
• explosions

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• Mining Regulation
• - Mining Law of 1872
• regulate mining of silver, copper, gold
  ore,
• natural gas and oil on federal lands
• - Surface Mining Control/Reclamation Act
• mandates that land disturbed must be
• reclaimed after mining process