(NOT FINISHED 4.3) Unit 4: Earth Systems and Resources

(4.1) Plate Tectonics

PLATES + BOUNDARIES

• Earth’s layers:

  • Lithosphere (crust)

  • Asthenosphere (upper mantle)

    • Oceans and land sit on top of layer

  • Mesosphere (lower mantle)

• Convergent plate boundary: plates that push towards each other

  • Causes volcanoes, rising magma, and earthquakes, trenches, island arcs

• Divergent plate boundary: plates that push away from each other

  • Has ridges/volcanoes

  • Causes seafloor spreading, hotspots

  • Less frequent earthquakes

• Transform plate boundary (aka Strike-Slip): plates that push past each other in opposite directions

  • No ridges/volcanoes

  • Shallow/frequent earthquakes

  • Causes fault lines

• Continental plates: plates that carry continents, earth, and rock

  • Less dense → float

• Plates might have several boundaries with other plates → diverse geological features

  • Can have breaks in surfaces → volcanic island change

    • EX: Japan, Indonesia, Hawaii

GEOLOGICAL FEATURES 

• Convection: movement of Earth’s tectonic plates that are driven by currents in the mantle layer

• Earthquakes: movement in the Earth caused on fault lines/plate boundaries

  • Occur at transform boundaries

  • Fault lines lock up/press to each other → builds up stress → energy releases

• Tsunamis: long sea wave that gets bigger as it reaches the coastline

  • Earthquakes, underwater landslides → tsunamis

  • Destroys habitats, drowns species, uproots trees, contaminates freshwater (w/ saltwater + debris) 

• Subduction Zone: one plate gets pressed under another plate that rises above it

  • Occur at convergent boundaries

(4.2) Soil Formation + Erosion

SOIL

• Parent material is weathered → transported → deposited → soil

  • Factors:

    • Type of parent material (soil contains the chemistry of the rock)

    • Climate (average temperature, moisture change of weathering, the nutrients in the moisture, and wind)

    • Topography (slope of land)

    • Biological factors (plants, animals, microorganisms)

    • Time (how long soil forms)

• Parent material: original rocks that are broken down to form the base of soil

  • Done by Weathering: breakdown of rock

• Soil profile (or Soil Horizons): layers of soil built up over time

  • O-horizon: organic matter

    • Contains organisms, leaf litter,

  • A-horizon: surface soil

    • Contains humus, organic material, some rock

  • B-horizon: subsoil

    • Surface soil but with more rock

  • C-horizon: substrata

    • Parent material

  • (R-horizon) = bedrock

EROSION

• Soil erosion: topsoil is stripped away by wind, water, gravity

  • Human factors: 

    • Deforestation (lack of roots that hold down the soil → replaced by plants that worsen erosion like wheat or soybean)

    • Overgrazing (cattle overeating → exposes topsoil)

    • Pesticides/fertilizers (changes chemistry of soil + kills microorganisms in soil)

    • Tilling (breaking soil prevents topsoil from getting organic material/roots)

  • Sheet erosion: surface layer is removed by water

    • Solution: maintain plant coverage

  • Rill erosion: small channels of water flow soil away

    • Solution: strip cropping/contouring tilling (low tilling)

  • Gully erosion: wider cuts in soil from expanded rill erosion

    • Solution: divert water away from rills or solve rill erosion

(4.3) NOT FINISHED

(4.4) Earth’s Atmosphere

• (4.4) Earth’s Atmosphere(4.4) Earth’s AtmosphereAtmosphere contains:

  • Nitrogen (78%)

  • Oxygen (21%)

  • Trace Gases (1%)

    • Argon → Carbon dioxyde → Neon → Helium → CH4 → Krypton → Hydrogen → Water

• Atmosphere layers

  • Exosphere (600-10,000 km)

    • enters space → drop in temperature

  • Thermosphere (85-600 km)

    • x-ray radiation + UV rays → rise in temperature

    • air’s still thin

  • Mesosphere (50-85 km)

    • thinning atmosphere → drop in temperature

  • Stratosphere (20-50 km)

    • radiation → rise in temperature

  • Troposphere (0 to 6-20 km) 

    • varies depending on location

    • densest layer

    • contains weather

(4.5) Global Wind Patterns

• Earth’s rotation → air circulates → predictability of wind patterns

  • Causes different ecosystems 

    • EX: Tropical climates near the equator

• Convection: cycle caused by earth’s rotation

  • as air expands, gets less dense and moves up to the poles → air heats,

  • as air compacts, gets denser and returns down → air cools down

  • repeats

  • exemplified in a Hadley Cell

• Coriolis Effect: Earth deflecting winds as it rotates 

  • Hot air from equator deflects → colder air

(4.6) Watersheds

• Watershed: area of land that drains water into a central body of water

  

  • Highest point/divide: highest point of watershed

  • Tributary: where water runs down from highest point

    • Transition zone

  • River: more water comes down

    • Transition zone

  • Delta: rivers join and water falls into basin (aquifer)

  • Groundwater/aquifer: the basin which has the runoff

• Characteristics of watersheds:

  • Area

  • Vegetation

    • More vegetation = water is absorbed in the soil → groundwater

  • Type of soil

    • Permeable soil = water in groundwater

    • Impermeable soil = runoff

  • Slope 

    • Steeper = runoff than absorb into the ground

• Human activity that affect watershed

  • Logging (removal of trees → sediment of soil runs in water)

  • Industrial sites (pollution → rivers)

  • Residential areas (waste, usage → quality or amount of water)

  • Cities (water runs off of streets)

  • Livestock/cropland (fertilizers + pesticides → quality of water)

  • Dams (blocks sediments that goes into natural habitats)

(4.7) Solar Radiation + Earth’s Seasons

• Insolation: how much solar radiation areas of Earth recieves 

  • Equator gets more concentrated insolation, poles get less (sun reaches farhter)

  • Solar radiation can get scattered over atmosphere

• Seasons happen because of Earth’s tilt, NOT Earth’s faces

  • Affects equinoxes, solstices, poles’ hottest/coldest days, 

    • EX: tropic of crapicorn = most solar radition during December, tropic of cancer = most solar radiation in June

(4.8) Earth’s Geography + Climate

• Air moves over water → water evaporates → air heats up

• Air continues to land → water condenses → cools down → falls (snow, rain, etc)

  • As it continues, air is less dense and gets slightly warmer

• Rain-shadow effect: how air moisture changes as air comes from the sea → mountain → land

  • Water evaporates with air over ocean → rises up the mountain on windward side (precipitation through rain) → condenses + cools down → less dense as it drops in leeward side

  • Windward side: side of a mountain facing coastline

  • Leeward side: side of a mountain facing inland

    • Arid climate because of effect

      

(4.9) La Niña + El Niño

• ENSO (El Niño Southern Oscillation): drastic extremes between El Nino, La Nina, and normal ocean circulation petterns

  • El Niño = hot, La Niña = cold

  • Takes place in equator

• Normal circulations

  • Trade winds bring warm temperatures from east to west 

    • Brings more wind and rainfall to Australian + Southeast Asia region 

    • Upwelling (cold, nutrient + oxygen rich water moves to the surface to replace warm waters blown away) in the Americas

    • Thermocline tilts from east to west (rises in east, lowers in west)

• El Niño 

  • Flips wind patterns

    • No upwellign and warmer water in Americas

    • Colder, drought conditions in Australia region

      • Flooding since region isn’t used to that much water

    • Thermocline levels

• La Niña

  • Extreme version of normal circulations, strong trade winds

    • Flash flooding in Australia region

    • Drier climate in Americas

    • More upwelling in Americas → more nutrient + oxygen rich water

    • Thermocline is steep