APES unit 4

4.1- Plate Tectonics

Convergent Plate Boundary:

  • Plates push toward each other

  • Typically causes volcanoes

  • Releases magma

  • May cause earthquakes

Divergent Plate Boundary:

  • Plates push away from each other

  • May have ridges or volcanoes

  • Typically causes seafloor spreading

  • May cause earthquakes less frequently

Transforms or Strike/Slip Boundary:

  • plates slide past each other

  • No ridges or volcanoes

  • Tend to have shallow earthquakes, more frequent

  • Underwater earthquakes are called tsunamis

Volcanoes- formed at plate boundaries

  • Oceans plates are denser than land plates

  • Ocean plate slips beneath land plate

  • This displaces molten rock beneath the surface

  • This molten rock is forced upward

Ring of Fire:

  • Coasts surrounding the Pacific Ocean

  • Plates meet and volcanic activity is high

Volcanoes are formed at hot-spots

  • Ocean plate slides over a fixed hot-spot (Hawaii, Japan, Indonesia)

4.2- Soil Formation and Erosion

Soil formation is a function of:

  • Type of parental material (rock broken down to form soil)

  • Type of organic material added (decaying plant/animal)

  • Climate (temperature, moisture change rate of weathering)

  • Topography (slope of the land may affect erosion)

Soil horizons:

O- organic layer

A- top soil

B- subsoil

C- parent material

R- bedrock

  • Layers that touch have the most similar material to each other

Erosion Factors:

  • Wind

  • Water

  • Gravity

  • Human factors (deforestation, overgrazing, pesticides and fertilizers, tillage practices)

  • Deforestation: lack of roots to hold down soil

  • Overgrazing: cattle overgrazing can erode soil

  • Pesticides and fertilizers: change soil chemistry and kill microorganisms in soil

  • Tillage practices: Turning and breaking up soil keeps top layers from amassing organic material and roots (solution is no till farming, yes contour plowing)

4.3- Soil Composition

on and Properties

Sand- largest particle, high permeability (water runs through easily)

Silt- middle sized particle

Clay- smallest particle, low permeability (risk of water logging)

Clay- used as an organic liner for things like landfills because it has such a low permeability

Soil triangle:

% clay diagonal from left to right

% silt diagonal from right to left

% sand horizontal

4.4- Earth’s Atmosphere

The atmosphere is a mix of different gases:

  • 78% nitrogen

  • 21% oxygen

  • 0.94% argon

  • .0.06% everything else

Thins with altitude

Troposphere- 

  • Weather

  • Cools as you go up because sunlight is absorbed on earth’s surface

Stratosphere-

  • Ozone layer

  • Ozone warms the layer

Mesosphere-

Thermosphere-

  • Auroras are found here

  • Hottest layer

Exosphere-

  • Upper Thermosphere

Insolation= (solar radiation/area)

-              Higher insolation at the equator due to more absorption

The earth is tilted at 23.5 degrees

The equator has the highest insolation because it has the most direct angle of sunlight

The poles have the lowest insolation

4.8- Earth’s Geography and Climate

  • Large bodies of water stabilize local temperatures

  • High specific heat: it takes more energy to heat water than it does to heat land because water can absorb more heat and solar radiation without raising its temperature

  • Low specific heat: temperature increases fast and heat is released fast because land does not absorb heat as well as water

Rain Shadow Effect: a dry area on the leeward side of a mountainous area. The mountains block the passage of rain, producing weather systems and cast a “shadow” of dryness behind them (warm air carrying moisture goes up, molecules come together and push out water which forms clouds, and dry air comes up and goes to the other side of the mountain, creating a shadow which is the dry side of the mountain)

  • Currents have a convection pattern, making east coast states warmer than west coast states (Gulf Stream carries warm water up on the east coast)

  • Ex. Brazil is warmer than Angola because there is a warm water current going past Brazil and a cold water current going past Angola

4.9- El Niño, La Niña (usually only in the Pacific Ocean)

Normal year- warm water travels west 

Upwelling- when surface water gets moved by wind, allowing colder water to come up (this water carries nutrients that help the whole ecosystem)

El Niño- water goes East

  • Warmer ocean temps in east pacific, drier in Australia, warmer and wetter un South America, warmer winter in the US, kind of like a cycle

  • Upwelling happens on the opposite side from where the surface water is getting moved

  • Normal wind patterns go from east to west

  • During El Niño, winds stall and ocean currents reverse

  • In this case, warmer water is driven to South America and there is no upwelling

La Niña- water goes West

  • Strengthening of normal wind patterns

  • Enhanced upwelling—> better food sources for aquatic life

  • Think hot boy, cold girl

Environmental Effects- changes for fish migration patterns, more phytoplankton production in La Niña cycles