Geography: Landforms and Processes

Plate Tectonics

• Theory that Earth's lithosphere (outer layer) is broken into large plates that move relative to each other
• Three types of plate movement:
  • Divergent: plates move apart, new crust forms
  • Convergent: plates collide, crust is destroyed or deformed
  • Transform: plates slide past each other horizontally
• Processes that shape the Earth's surface:
  • Continental drift: movement of continents
  • Seafloor spreading: creation of new oceanic crust

Mountain Formation

• Three main types of mountain formation:
  • Volcanic: formed by volcanic activity
  • Fold: formed by plate convergence and folding
  • Block: formed by faulting and uplift
• Mountain-building processes:
  • Orogenesis: formation of mountains through plate collision
  • Uplift: vertical movement of the Earth's surface
  • Denudation: wear away of existing mountains

Volcanic Landforms

• Types of volcanic landforms:
  • Shield volcanoes: gently sloping, broad volcanoes
  • Stratovolcanoes: tall, conical volcanoes
  • Calderas: large depressions formed by volcanic collapse
  • Volcanic fields: areas of numerous small volcanoes
• Volcanic features:
  • Volcanic cones: accumulation of lava and ash
  • Lava flows: streams of molten rock
  • Volcanic ash: small particles ejected during eruptions

Coastal Features

• Types of coastal landforms:
  • Beaches: areas of sediment deposited along the coast
  • Dunes: ridges of sand formed by wind
  • Cliffs: steep slopes formed by erosion
  • Headlands: rocky areas that project out to sea
• Coastal processes:
  • Erosion: wear away of the coast by wind and water
  • Deposition: accumulation of sediment along the coast
  • Longshore drift: movement of sediment along the coast

Desert Landforms

• Types of desert landforms:
  • Dunes: ridges of sand formed by wind
  • Playas: dry lake beds
  • Badlands: areas of eroded sedimentary rock
  • Oases: areas of vegetation in the desert
• Desert processes:
  • Deflation: removal of sediment by wind
  • Desertification: expansion of desert areas due to climate change
  • Eolian erosion: wear away of rocks by wind-borne sediment