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
- %%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.