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.