U4: Earth Systems and Resources

• The lithosphere is the solid outer layer of the earth, including the crust and upper mantle
• Tectonic plates are slabs of rock floating on top of the mantle. They make up the lithosphere.
• The mantle is a molten magma sea kept in liquid form due to heat from the Earth's core.
• The core is a dense ball of nickel, iron, and radioactive elements
• Convergent Boundaries are when two plates collide, and one subduct/goes underneath another.

  There are three forms: oceanic-oceanic, oceanic-continental, and continental-continental.
• Oceanic-oceanic convergences create deep trenches and volcanic island arcs.
• Oceanic-continental convergences create mountain ranges like the Andes Mountains. They are likely to be on the outskirts of a continent.
• Continental-continental convergences create mountain ranges like the Himalayas. They are likely to be in the middle of a continent.
• Divergent plate boundaries are plates that move away from eachother due to rising magma forcing the two plates apart.

  Divergent plates usually occur at sea floors. They are also called oceanic spreading ridges.
• Transform boundaries are two plates that slide past each other in opposite directions. They get caught on each other, and when sliding fast enough, they release the stress/pressure.

  The release of the stress forms shockwaves.
• Shockwaves grow fainter and fainter as they stray from the origin point. Their damage becomes less and less.
• Hot spots are areas of magma rising to the surface of the Earth's crust. Volcanoes usually form on top of these hot spots from magma eruptions.
• Convection cycles are caused by differential heating of the Earth's surface due to cycles of heating and cooling magma.
• When magma rises, it cools and solidifies. The mid-oceanic ridge is formed by this process, from the spreading of oceanic crust.

  
• Seafloor spreading is the idea that new seabed is created along divergent plate margins where molten rock (magma) pushes up through the Earth's crust. This causes the crust to spread outwards.
• The spreading magma forces oceanic plates under continental plates in subduction zones.

  This is forms an oceanic-continental convergent plate boundary.
• Transform boundaries occur when two tectonic plates slide past each other horizontally. They do not create or destroy land but instead move existing land around.
• Divergent plate boundaries form:

  • Mid-Oceanic Ridges
  • Volcanoes
  • Sea floor spreading
• Convergent plate boundaries form:

  • Mountains
  • Island Arcs
  • Earthquakes
  • Volcanoes
• Transform fault boundaries form:

  • Earthquakes
• Soil is a mix of geological and organic compounds.
• Soil is formed when parent material is weathered, transported and deposited (through erosion).
• The soil profile consists of the A horizon, B horizon and C horizon. The A horizon contains decomposed plant matter and minerals from the upper layers of rock. It also has air spaces between particles that allow water to drain through it. The B horizon is where clay and silt are concentrated due to leaching. This layer can be very fertile as it retains nutrients well. The C horizon is made up of unweathered bedrock.
• Types of weathering:

  1. Physical - Wind, rain, freezing and thawing of ice
  2. Biological - degradation of roots of trees, cracked rocks
  3. Chemical - Acid rain, acids from moss
• Humus is the broken down biomass, dead animals, plants, and organic waste.
• Leaching occurs when soluble materials dissolve into groundwater or surface water.
• Erosion is the transport of sediment by water, wind, or ice.
• irrigation - Supplying land with water through a network of canals
• Fertility - a measure of how well soil supports plant growth
• Contour plowing - Method of plowing that follows the curve of the land to reduce soil erosion.

  
• Types of Erosion into water

  1. Sheet Erosion - surface layer is removed by water
  2. Rill Erosion - small channels of water flow
• Solutions to erosion - maintaining plant coverage over topsoil, strip cropping, and contour plowing.
• Plate tectonics are huge slabs of rock or lithosphere that float on top of the molten mantle
• Divergent boundaries occur when plates move away from each other, causing seafloor spreading
• Convergent boundaries occur when plates collide, leading to subduction and the formation of volcanic mountain ranges
• Transform boundaries occur when plates slide past each other in opposite directions, often resulting in earthquakes
• Soil is a complex mixture of weathered rocks, organic material, and pore space
• Soil forms through the weathering of rocks by forces like rain and freeze-thaw cycles
• Soil has different layers or horizons: O Horizon (organic matter), A Horizon (topsoil), B Horizon (subsoil), and C Horizon (parent material).
• Weathering is the breakdown of rocks into smaller pieces, while erosion is the movement of those rock pieces by wind and rain.