CLASSIFICATION OF GLACIERS

CLASSIFICATION

• Morphological Classification – based on form and size of ice
• Dynamic classification – based on degree of activity of ice
• Thermal classification
  

THERMAL CLASSIFICATION

1. Temperate Glacier (warm)

o At pressure melting point throughout thickness except winter when uppermost layer is temporarily colder
o Glaciers of Alps and Southern Scandanevia
o Meltwater exists at its bed so flows fairly easily
o Rapid rate of firnification
o Summer melting both in accumulation and ablation zone

2. Cold or Polar Glacier

o Subpolar type – surface melt and water present
o High polar type – temperature of firn below freezing point, no melting in summer
o Geomorphologically no basal meltwater

DYNAMIC CLASSIFICATION

Active
Passive
Dead Glaciers

1. Active Glaciers
   

• Fed by continuous ice stream from an accumulation zone in a cirque basin or a plateau
• Subgroup – regenerated type – fed by ice avalanches falling from upper accumulation area to lower ground
• Outlet Glacier – fed by avalanches at Morsarjokull in Iceland
• Active glaciers have net total budget, does not depend on positive or negative budget
  

2. Dead Glaciers
   

o Not necessarily immobile
o Does not receive ice from an accumulation area
o Low ground where flow induced by slope is low
o Vale of Belvoir, Norrland in Sweden

MORPHOLOGICAL CLASSIFICATION

1. Niche, wall-sided or cliff glacier

• Triangular wedge of ice, slightly convex surface lying in a shallow funnel shaped hollow
• On steep slopes
• Gully runs from the glacier lower end to the alluvial fan below
• Spitsbergen

2. Cirque Glacier
• Jotunheim, Norway
• Vesl-Skautbreen
  

3. Valley Glacier - Alpine type

o Snowline falling in elevation, ice of cirque can move out of basin and down the valley to form a valley glacier
o Several cirques combimes to form valley glacier
o Alhamann’s divison – 4 types

i. Rhone Glacier or Hintereisfermer – Considerable portion above their median height
ii. Grosser Aletschgletscher – High Level neve Basin, Greatest part occurs in Upper part of Glacier Basin
iii. Glaciers that have most of their area at lowlevels and are fed by avalanches from higher snowfields – glaciers of Central asia, Styggedalsbreen, Norway
iv. Greater portion of their area a little below mean elevation – Spitsbergen

4. Valley Glacier – Outlet type

o Iceland – Norway
o Fed by ice cap, not by cirques
o Wider and flow with considerable rapidilty on steep slopes

5. Transection Glacier

o Lowenskjold glacier
o Occupy much of a mountain group from which glaciers flow in several directions into a system of radiating valleys
o Transfluent glacial breaches and cols

6. Piedmont Glacier

o Malaspina Glacier, Skeioararjokull, Vatnajokull
o Valley Glacier advances out from the containing mountain walls into lowland beyond

7. Floating ice tongue & ice shelves

o Floating Ice Tongues - Restricted to high latitude where glaciers reach the sea, Steensby Gletscher in Northe Greenland, Petermanns Gletscher, Ryder Gletscher
o Ice Shelves – characteristics of Arctic Rosss Ice Shelf

8. Mountain Ice cap

o Vatnajokull in Iceland, Jostedalsbreen in Norway
o Accumulation area from where outlet glaciers flow

9. Glacier Cap or Lowland ice-cap

o Arctic regions of northern Canada, Barnes Ice Cap
o Ice masses in Lowland

10. Ice-sheets

o Ice sheets