4.1 vocab

• Core:

  Made of nickel and iron; solid inner core, liquid outer core
• Mantle

  contains magma that slowly circulates in convention cells
• asthenosphere

  semi-molten, ductile rock
• lithosphere

  brittle, outermost layer
• Hot spots

  a place where molten material from the mantle reaches the lithosphere
• Magma


  molten rock
• seafloor spreading


  Magma rising from the mantle and creating new seafloor

  • Caused by divergent plates
• subduction

  the process of one plate passing under another

  • denser plate sinks under the less dense plate
  • new lithosphere is added and old lithosphere is recycled into mantle
• fault

  a fracture in the rock caused by movement of the Earth's crust

  • causes seismic activity
• fault zone

  a large expanse of rock where a fault has formed
• divergent plate boundaries

  area where plates move away from each other

  • seafloor spreading
  • rift valley
  • mid-oceanic ridges
  • volcanos
• convergent plate boundary

  area where plates move toward each other

  • can cause a subduction zone
  • mountains
  • island arcs
  • volcanos
• transform plate boundary

  area where plates slide past each other

  • earthquakes
• richter scale


  measure of the largest ground movement that occurs during an earthquake
• earthquake

  sudden movement of Earth's crust causes a release of potential energy along a fault causes vibration or movement at the surface
• epicenter

  the exact point on the surface of the Earth directly above where a rock ruptures during an earthquake
• physical weathering

  mechanical weathering of rocks and minerals; can be caused by water, wind, or variations in temperature
• chemical weathering

  the breakdown of rocks and minerals by chemical reactions, the dissolving of chemical elements from rocks, or both
• O horizon

  Found at the surface of soil;organic matter (detritus) in various stages of decomposition
• A horizon

  Topsoil; zone made up of overlying organic material and underlying mineral material
• E horizon

  A zone of leaching (removal of minerals from soil)
• B horizon

  zone made up of mostly minerals and lacking in organic material
• C horizon

  least weathered horizon; very similar to parent material
• permeability

  how quickly soil drains

  • sand drains the quickest and clay the slowest
• erosion


  the physical removal of rock fragments from a landscape or ecosystem
• acid precipitation

  precipitation high in sulfuric acid and nitric acid
• parent material

  the rock material from which inorganic components of the soil are derived
• humus

  most decomposed organic material found at the lowest part of the O horizon
• cation exchange capacity

  the ability of a particular soil to absorb and release cations
• base saturation

  the proportion of soil bases to soil acids, expressed as a percentage