SS

Unit 4 - Earth Systems & Resources 

4.1 Plate Tectonics

  • %%layers of the Earth%%: crust (lithosphere), upper mantle (asthenosphere), and mesosphere (lower mantle)
  • %%plates%%: sit on the asthenosphere or upper mantle; move in all directions; can be continental or oceanic & have multiple boundary types
  • %%plate boundaries%%: separates layers of the Earth; varies globally
    • ^^convergent plate boundary^^: plates push toward each other
    • causes volcanoes, releasing magma & earthquakes
    • ^^divergent plate boundary^^: plates push away from each other
    • volcano ridges or mountains
    • can cause earthquakes
    • ^^transform (strike-slip) plate boundary^^: plates slide off each other
    • no ridges or volcanoes; shallow frequent earthquakes
  • %%earthquake formation%%: occur at fault lines or plate boundaries → builds up stress/energy → release of energy causes the earth to shake
  • geologic events help to ==identify plates== by creating a pattern of similar area
    • effects of geologic events: earthquakes, volcanic eruption, and tsunamis
  • ^^tsunamis^^: long sea wave
    • can be caused by underwater landslides and earthquakes
    • can cause contaminated water, uplifting trees, and damage to life on land

4.2 Soil Formation and Erosion

  • %%soil%%: forms from the weathering (mechanical process of breaking down rocks of parent materials (broken down rocks)
    • ^^type of parent material^^: influences soil chemistry
    • ^^climate:^^ avg temperate, moisture, weathering rate, nutrients, wind redistribution
    • ^^topography^^: affects erosion (slope of the land)
    • ^^biological factors^^: microorganism, plant & animal use
    • ^^time^^: neverending, continuous
  • %%soil profile%%: combination of soil layers from various types of rock & organism matter
    • ^^surface horizon^^: basic rock material + human/organic material
    • ^^subsoil^^: more basic material than organic matter
    • ^^substrata^^: most parent material
    • ^^bedrock^^: granite, basalt, limestone, sandstone, etc.
  • %%soil erosion%%: weathering of soil
    • caused by water, wind, gravity, human factors → water contamination
    • ^^human impact on soil erosion^^: deforestation (lack of roots on soil) overgrazing (overeating leads to overexposure of top soil layer → vulnerable to wind & rain)
    • ^^pesticides/fertilizers^^: changes soil chemistry, kills beneficial microorganisms
    • ^^tillage^^: breaking up soil → preventing it from organic matter accumulation for nutrition
    • ^^sheet erosion^^: surface layer is removed by water; prevented by maintaining plant cover
    • ^^rill erosion^^: small channels of water flow in soil → strig cropping or contour plowing)
    • ^^gully erosion^^: wide cuts in soil from rill erosion → diverting water to other streams and flows

4.3 Soil Composition & Properties

  • soil = sand + silt + clay
    • ^^sand^^: 2 mm to 0.05 mm (allows water to pass through)(takes 1 hour)
    • ^^silt^^: 0.05 mm to 0.002 mm
    • ^^clay^^: < 0.002 mm (blocks water from passing through)(takes 100 years)
  • soil composition is determined by the percentage of each soil particle → influences soil type (@@soil triangle@@)
  • %%soil test%%: the process of assessing soil content and attributes
    • ^^chemical^^: nitrogen, phosphorous, pH/acidity
    • fertilizers = increase in nutrients (nitrogen, phosphorus, potassium)
    • tend to have 7.5 pH (basic)
    • rainfall → increases acidity
    • ^^physical^^: soil composition & water holding capacity
    • amount of sand, silt, and clay → percolation/infiltration
    • percolation: water → ground
    • infiltration: ions/chemicals → ground (same process as percolation)
    • ^^biological^^: microorganisms
    • contains bacteria, archaea, fungi, earthworms, burrowing animals, etc.

4.4 Earth’s Atmosphere

  • atmosphere = 78% nitrogen + 21% oxygen + 1% trace gases (argon, co2, methane, krypton, hydrogen, water, etc.)
    • exosphere: 600-10,00km; continues to rise until outer space
    • thermosphere: 85-600km; rise in temperature due to UV rays
    • mesosphere: 50-85km; drop in temperature as air thins out
    • stratosphere: 20-50km; rise in temperature from ozone formation
    • troposphere: 0-6-20km; air is most dense

4.5 Global Wind Patterns

  • air circulates as earth rotates
  • convection: changes in density temperature
  • coriolis effect: earth’s rotation deflects the wind (hot air in moving but also turning at the same time)
    • leads to routine weather patterns in both hemispheres

4.6 Watersheds

  • watershed: highest point/divide in a river
    • tributary: smaller streams meet larger river
    • delta: river meets larger body of water
    • aquifer: groundwater under the river
  • source zone: where the water in the river comes from
    • ex. ice cap
  • transition zone: after the headwater; clear cold full oxygenated
  • floodplain: more sedimentation → less oxygenated filled with more nutrients
  • rainwater → runs downhill to river or percolates through the soil to groundwater

4.7 Solar Radiation & Earth’s Seasons

  • primary energy source: solar radiation (constant)
  • insolation: incoming solar energy
    • = solar radiation/area
    • surface most perpendicular to the sun (equator) = highest insolation
    • smaller angle = larger area of solar radiation spread = smaller insolation value
    • areas near the pole = lower levels of insolation
    • amount of energy is determined by latitude and season
  • northern hemisphere seasons:
    • winter solstice: december 21-22; shortest day of the year, polar night
    • autumnal equinox: september 22-23; day = night
    • summer solstice: june 20-22; longest day of the year, midnight sun
    • vernal equinox: march 20-21; day = night
  • southern hemisphere seasons:
    • equinox days are the same (opposite of the northern hemisphere)
    • longest day: december 20/21
    • shortest day: june 20/21

4.8 Earth’s Geography & Climate

  • land - low specific + no mobility = quicker temperature increase
    • specific heat = amount of energy needed to raise temperature per degree
  • water - high specific heat + high mobility = slower temperature increase
    • coastal areas have more stable temperatures as a result of the intersection between water and land (stabilization of temperatures in both parts)
  • currents: bodies of water that flow around a piece of land
    • warmer currents bring heat to land, raising temperatures in certain areas and providing humidity
    • ex. brazil, england
    • cooler currents bring coldness to land, dropping temperatures in certain areas and decreasing humidity
    • ex. canada, angola
  • rainshadow effect: effect of coastal breezes from the ocean on mountains
  • windward side: part of the mountain next to the ocean
    • air rises from the ocean currents → moisture rises → condensation, precipitation, vegetation → cools temperature on the mountain
  • leeward side: part of the mountain inland
    • air becomes hot and dry → decreases moisture → arid and dry as it comes down the mountain
  • deserts form 30 degrees above and below the equator

4.9 El Niño & La Niña

  • enso: el nino southern oscillation
    • series of weather events happens every 3-7 years in southern hemisphere (south america and australia)
  • normal wind patterns: wind goes from east to west → causes upwelling of phytoplankton (greater nutrient supply)
  • el nino: winds stop traveling or reverse; currents reverse → suppressing upwelling of life → decreased fishing commercialization
    • begins in december to february until june to august
    • countries surrounding australia experience dry weather → droughts, wildfires → habitat destruction
    • countries surrounding south america experience warm & wet conditions → flooding, landslides, etc.
    • pacific jet stream → warmer winters in canada & north america; wetter and colder in southern states; dry winters in midwest usa
    • midwest → drier conditions
  • la nina: enhanced neutral conditions
    • stronger currents, wind patterns, etc.
    • warm current moves closer to australian shoreline
    • greater upwelling in south america. (more phytoplankton)
  • normal ocean currents: warm current goes from south america to australia → cools down in australia → comes back to south america in oceanic life (upwelling)
    • increased risk of floods and landslides
    • cooler places get cooler and wetter weather, warmer places get warmer
    • polar jet stream → colder winters, drier in midwest and south usa, warmer upper midwest, etc.

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