L1 - Glacier Formation Flashcards
How do glaciers form?
Via compaction of snow flakes and the removal of air bubbles which leads to granular snow then firn and then glacier ice
What is defined as glacier ice?
Ice that has survived more than one season
What 2 factors influence the survival of snow over the summer season?
- The Angle of the Sun
2. Climate
What influences the formation of tropical glaciers?
Lapse Rates (Elevation and Temperature)
What are the 2 controls on glacier formation?
- Topography
2. Hydrology
Name 5 types of glaciers that are constrained by topography?
- Cirque
- Valley
- Tidewater
- Piedmont
- Hanging Glacier
What are the 2 main types of glaciers that are unconstrained by topography?
- Ice Sheet
2. Ice Cap
What is the difference between an ice sheet and an ice cap?
An ice sheet covers almost 100% of the land whereas an ice cap doesn’t and tends to be
Name 2 locations where ice shelves are common?
- Canadian Arctic
2. Larsen, Antarctica
Where has most research been done?
On mountain glaciers
Which glacier accounts for the most of the global coverage?
Antarctica
What is the current concern regarding glaciers?
There is an acceleration in worldwide retreat
What have the valleys under the AIS been compared to with regards to their size?
The Grand Canyon
Underneath the Greenland Ice Sheet a trough has recently been discovered, what has its depth been compared to?
The height of the Eiffel Tower
Name 2 Paleo Ice Sheets
- British Irish
2. Laurentide
Name 4 reasons why glaciers are important
- Water Resources
- Hazards
- Sea Level Rise
- Climate Feedback
Name 2 locations where glacier outburst floods are common
- Iceland
2. Nepal
What does GLOF stand for?
Glacial Lake Outburst Flood
If you were to melt all of the worlds glaciers what level sea level rise would this equate to?
~80m
What are the 4 types of Glacier related Sea Level Change?
- Glacioeustasy
- Glacioisostasy
- Geodial Isostasy
- Steric Sea Level Change
What is Glacioeustasy?
When glaciers lock up water from the water cycle
What is Glacioisostasy?
When the Earth’s crust is depressed by the weight of the ice sheets – it rebounds following the LGM
What is Geodial Isostasy?
Ice sheet mass can cause changes in the Earth’s gravitational field
What is Steric Sea Level Change?
Decreases in water density and increases in temperature can cause expansion of the oceans above 4DegC
What is the Ice Albedo Feedback?
Ice sheets have a high albedo –> this means that they have high reflectivity –> this means less radiation is absorbed –> this leads to localised cooling
