Glaciers

• Glaical Budget


  Input and output of a glacier
• Factors that affect Glacial budget

  • Altitude
  • Latitude
  • Temperature
• Ablation


  loss from glacier
• Accumulation


  Snow/ice/rock added to the glacier
• Firn


  Compressed snow that is not ice
• Accumulation peaks in winter and Ablation peaks in summer
• Freeze-thaw weathering

  • Water gets into the joints (cracks) in the rocks. At night water freezes
  • Ice expands and puts pressure on the joints
  • Bits of rock (scree) break off
• Abrasion

  • As glacier moves along a valley floor, rock gets caught in glacier's base
  • The rock fragments scrape along the valley floor
  • Over time valley is deepened and smoothed
• Plucking

  • By day some surface water may melt, meltwater trickles into rock joints
  • At night, water freezes around the rocks
  • Glacier moves downhill ; the rocks are plucked (pulled) away from the valley
• FORMATION OF A GLACIER

  1. Snow remains in the same area year-round, slowly transforming to ice
  2. Each year, new layers of snow compress and bury previous layers
  3. Compression forces the snow to re-crystallize, forming grains similar in size and shape to grains of sugar
  4. Gradually, grains grow larger and air pockets between the grains get smaller, causing snow to compact and increase in density
  5. After 2 winters, snow turns to firn- middle state between snow and glacier ice
  6. For most glaciers, this process takes more than 100 years
• Glacial trough formation


  As glacier advances into the valley it bulldozes and erodes the river that was previously there, due to its size it changes the v-shaped river valley into a glacial trough by plucking rocks which do abrasion - eroding the rock by sandpaper effect
• Hanging valley formation


  Similar to formation of a glacial trough but formed through tributary glaciers. This means they don't have as much force so they don't erode as deep. This leaves hanging valleys which can have waterfalls
• Acronym for corrie formation

  • A ccumulation
  • R otational
  • S lip
  • E rosion
• Corrie formation

  1. Accumulation- Snow accumulates in hollow and turns to ice. This happens due to new layers of snow piling up and compressing the old ones over many years
  2. Rotational Slip - Hollow is filled with ice. Ice moves downslope due to gravity. This causes a rotational slip movement. This deepens the hollow
  3. Erosion - Ice plucking and abrasion make the hollow deeper. The rock lip is make due to reduced ersosion at the front of the corrie due to thinner less erosive ice. Sometimes morraine is deposited here. After ice has melted, deep bowl shaped hollow left behind (tarn)
• Glacial period


  Time period when there was a large presence of ice on the surface of the planet
• Ice Age

  Caused by the earth's orbit around the sun being eliptical meaning when the earth is a greater distance away from the sun the temperature drops
• Arête


  If two corries form next to eachother they will leave a sharp ridge between them. (Comes from french word arête meaning stop!)
• Pyrimidal Peak


  When three or more corries form around a mountain. They cut backwards to leave a 'horn' or pyrimidal peak in the middle
• Three different erosional landforms

  Corries, Arêtes, Pyramidal Peaks
• Relief


  Shape of the land
• Relief of the Uk is unneven
• Erratics


  As glacier advances, it picks up rocks. When it retreates erratics are the rocks that have been deposited by the glacier, often not fitting in with the geology of the area they have been dropped. Think sticks and carrots of a snowman!
• Drumlins


  Elongated egg-shaped hills made up of glacial till that form beneath a glacier when it meets an obstruction and material is deposited as ground moraine
• Front of Drumlin

  Stoss
• Back of Drumlin

  Lee slope
• Truncated Spur


  Found inbetween hanging valleys, they look like upside down V. They form when past ridges get cut off by lower valley glaciers
• Ribbon lake


  When Glacier melts, water collects in deeper areas of a glacial trough creating a long thin lake
• Moraines


  Unsorted glacial till deposited in mounds
• Lateral moraines


  Found at the sides piled on top of the glacier
• Medial Moraine


  Formed when two glaciers meet
• Terminal moraine


  Enormous ridge that gets bulldozed by snout of glacier (deposited at snout)
• Ground Moraine


  Material dragged under the base of the glacier and is left underneath the glacier on the floor
• Glacial till


  Material carried/moved by the glacier
• Front of Glacier

  Snout
• Four types of moraines

  Ground, Terminal, Lateral, Medial
• Main economic uses in an upland area

  • Forestry
  • Farming
  • Quarrying
  • Tourism
• Why does quarrying take place in upland areas


  Glacial erosion has exposed valuble sources of stone and minerals like lead, copper, graphite and coal. Can get Slate and Granite
• Use of Slate


  Building and roofing materials for homes
• Use of Granite


  Pavement Blocs and kitchen countertops
• Why does toursim take place in upland areas


  Dramatic landscapes are attractive to visitors and there are are variety of activities to do like hiking, climbing, biking etc. It also boosts the local economy and provides a variety of jobs