part 5

PART 1: EFFECTS OF GLACIERS

  • Why do we care?

    • Source of freshwater

    • Seasonal regulation

    • Contribution to sea level rise

    • Vulnerability to cliamte change

    • Climate change proxies

    • Feedback loop

    • Habitat for unique species

    • Influence on river systsems

    • Tourism

    • Natural hazards

    •  global indicator of enviornmental health

  1. Alters thermohaline circulation (blue and red chart)

  2. Sea level change

    1. Melt all glaciers = sea lebel rise about 65m or 200 ft

    2. Glaciers trap huge amounts of water

  3. Isostatic depression

    1. E antarctic ice sheet has caused up to 2.5 km of isostatic depression

      1. Glacier --> crust subsidence --> moves horizontally outward

  4. Isostatic rebound

    1. Moves horizontally inwards --> crust rebound moving up vertically

  5. Drinking water and irrigation

    1. Ex- washington get 470 billion gallons/year

 

 

PART 2: GLACIER BASICS

  • GLACIER- large mass of ice that forms from the accumulation, compaction, and recrystallization of snow over many years.

  • Forming a glacier

    • Granular snow

    • Firn (denser)

    • Glacial ice

    • Requires time, cold, and precipitation

  • Types of glaciers

    • Valley glacier aka mountain, alpine

      • Ex- mt kilimanjaro- africa ca 20k feet

    • Continental glacier

      • Aka ice sheets

  • Glacial movements

    • Accumulation- process by which snow and ice build up in a glacier or snowpack over time

    • Ablation- processes through which a glacier loses mass, primarily through melting, sublimation, and calving.

      • Both accumulation and ablation need each other

    • Firn line- critical boundary on a glacier that separates the accumulation zone from the ablation zone

    • Speed varies in different parts of a glacier

      • Upslope v downslope

    • Things stuck in the ice get moved

    • Plastic flow- > 50 m thick

    • Basal slip- process by which glaciers move over their bed (the ground beneath the glacier) due to the presence of water and the gravitational force acting on the ice

  • Glacial feature

    • Crevasse- deep, vertical fracture or crack that forms in a glacier or ice sheet

 

PART 3: GLACIAL EROSION

  • Abrasion- involves the wearing away and smoothing of a surface through friction and erosion caused by the movement of particles

  • Plucking- occurs in glacial environments, where a glacier picks up and removes pieces of rock and sediment from the underlying bedrock as it moves

  • Erosive features

    1. Striations

    2. U shaped valleys

    3. Cirque

    4. Tarns

    5. Horn

    6. Arete

    7. Roche moutonnée

 

PART 4: GLACIAL SEDIMENT DEPOSITS

  • Erratics

  • Till

  • Outwash

  • Loess

  • DEPOSITIONAL FEATURES AND EROSIONAL FEATURES ARE DIFFERENT

  • Depositional features

    1. Moraines

    2. Eskers

    3. Drumlin

    4. Kames

    5. Kettle lakes (kettles)