EES Exam 3

• Weathering


  Breaks down rock at Earth's surface and to some depth below the surface, either disintegrating rock into particles or dissolving it in water - always in place
• Types of weathering


  • Physical (mechanical) weathering
  • Chemical weathering
• Physical (mechanical) weathering


  • Process of rock breakage without chemical alteration
• Chemical weathering


  • Explains actual decomposition and decay of constituent materials in a rock and always in the presence of water
• Frost wedging


  Constant freezing and thawing of ice
• Thermal expansion


  No water, related to daily and seasonal temperature changes causing materials to expand when warm and shrink when colder (constant heating and cooling)
• Salt-crystal growth


  Occurs as a result of disintegration of rocks due to growth & expansion of various salt crystals
• Exfoliation


  Rock peels or slips off in sheets instead of grains and bulks
• Spheroidal weathering


  Perfect circle that affects jointed bedrock and results in the formation of concentric spherical layers of highly decayed rock
• Hydration


  Water becomes a part of the chemical composition of the mineral forming a hydrate
• Hydrolysis


  Decomposition of a chemical compound by water
• Oxidation


  Occurs when certain metallic elements combine with oxygen to form oxides
• Dissolution of Carbonates

  Occurs when specific solutions sometimes formed from water and carbon dioxide dissolves minerals
• Factors influencing weathering rates

  • Rock composition and structure (parent material)
  • Climate (precipitation and temperature)
  • Slope orientation
  • Subsurface water
  • Vegetation
  • Time
• Differential weathering


  Weathering that occurs at different rates based on composition and resilience as well as intensity of the weathering
• Alcove


  Arid landscape but geographic and geological term for steep-sided hollow sin the side of an exposed rock face or cliff of a homogeneous rock type, that was eroded; commonly formed by chemical and physical weathering along the horizontal discontinuities where water and salt concentrate
• Karst


  Landscape formed by chemical weathering primarily due to groundwater movement (limestone, or >70% calcium carbonate)
• Key karst formation processes

  • Solubility of bedrock
  • Climate (temperature and moisture)
  • Structure of limestone
  • Vegetation/pH levels of water
  • Atmospheric CO2
• Features associated with karst topography or landscape

  • Caverns/Caves
  • Sinkholes
  • Disappearing Streams
  • Springs
  • Towers
• Pseudokarst


  Karst-like development in non-carbonate lithology exhibit characteristics similar to karst landscapes
• Locations of pseudokarst systems

  • Hydrothermal/volcanic regions (Hawaii and NW U.S.)
• Mass movement


  Downward slope of a body of material made up of soil, sediment, or rock all propelled by gravity (greater slope angle = more susceptible to the mass wasting process)
• Conditions that lead to slope failure


  • Prolonged/torrential rain & saturated soils
  • Slope becomes over steepened
  • Volcanic eruptions melt snow and ice causing fluid debris downslope into river channels
  • Earthquakes shake debris loose or fractures rock that may be key stabilizer in over-steepened slope
• Types of mass movement

  • Fall
  • Slides
  • Flows
  • Creeps
• Snow avalanche


  Natural hazard consisting of a sudden release and movement of massive amounts of snow down a mountain slope, each snow layers properties and relationship between them can determine its susceptibilities
• Types of avalanches


  • Powder
  • Slab
  • Wet
• Processes leading up to snow avalanche

  1. Areas with overloading of snow

  2. Increase/decrease in temperature causing brittleness and tension

  3. 25-60 degree slope angles

  4. Snowpack conditions (topheavy)

  5. Vibrations

  6. Earthquakes
• Mountain areas in arctic and temperate regions, which tend to be more severe in Europe than in North America due to higher population densities in Alp regions
• Avalanche management techniques


  • Intentional avalanche release
  • Managing ski traffic
  • Cornice management
• Glacier


  Located in the cryosphere and form at high latitude and high elevations at any latitudes, consisting of a large mass of ice resting on land or floating as an ice shelf in sea adjacent land that move slowly in stream-like patterns
• Types of glaciers


  • Alpine Glaciers (Valley, Cirque, Piedmont, Tidewater)
  • Continental Glaciers
• Contrast ice shelves, ice fields and ice caps

  • Ice shelf - extends over sea
  • Ice cap - covers less than 50,000km of land and is a circle shape
  • Ice field - elongated patterns over a mountain region (patagonia)
• Common features of a glacier


  • Crevasse
  • Moraine (Medial, Lateral)
  • Terminus
• Glacial mass balance


  Determines whether a glacier expands or shrinks as it is a dynamic and open system depending on inputs and outputs
• Accumulation zone


  Area where glaciers acquire snow, usually at highest elevation or in cirque
• Ablation zone


  Area where glaciers undergo most reduction/wasting
• Effects of glacier loss

  • Local: water available for plants, animals, recreation but creates issues of runoff and hazards
  • Regional: provides drinking water, also for fisheries and agriculture, as well as impacts tourism
  • Global: changes sea level rise, surface energy balance of Earth, and the ocean circulation influence
• V-Shaped Valleys are created by

  flowing waters
• U-Shaped valleys are created by 


  Glaciers
• Weathering occurs 


  In place