GL 2 Flashcards
What is the cryosphere?
Parts of the crust and atmosphere that are below zero degrees for a part of the year
How are icebergs formed
Broken of of glaciers into water via calving
What is permafrost
permanently frozen ground
What is the morphology of glaciers?
Form, shape and structure of ice
What two factors impact the morphology of a glacier?
Climate and topography of land
What is climate? And how does it impact a glacier’s morphology
Climate is contorlled by annual temperature cycle. Warmer climate causes negative mass balance vice versa.
What is topography? And how does it impact glaciers morphology?
Topography is the natural shape of the land. Land surface, e.g. altitude. Controls physical dimensions of the glaciers and how they can flow.
What is an unconstrained land mass?
morphology and flow pattern that is not fully dependent of the topography of land
What is a constrained ice mass?
Morphology and flow pattern that is strongly based on topography
Ice sheet:
Description, size, constrained or unconstrained?
Example
Topography is submerged in ice, forms gently sloping domes of ice several km thick. +50,000km2. Unconstrained. Antarctic ice sheet
Ice cap:
Description, size, constrained or unconstrained?
Example
Smaller version of an ice sheet. >50,000km2. Unconstrained. Vatnajökull ice sheet
Ice field:
Description, size, constrained or unconstrained?
Example
Ice covering upland area, does not bury topography. 10-10,000km2. Constrained. Patagonian ice fields
Valley glacier:
Description, size, constrained or unconstrained?
Example
Confined between valley walls, finishing in a narrow tongue, made from ice caps, sheets or cirques. 3-1500km2. Constrained, Aletsch glacier, Swiss Alps
Piedmont glacier:
Description, size, constrained or unconstrained?
Example
Valley Glacier that extends beyond end of a mountain into flat area, spreading out. 3-1000km2. Constrained. Malaspina, Alaska
Cirque glacier:
Description, size, constrained or unconstrained?
Example
Occupies a hollow on a mountain side, calves out a corrie. 0.5-0.8 km2. Constrained. Styggebrean Norway
Ice shelf/sea ice:
Description, size, constrained or unconstrained?
Example
Large area of floating glacier ice, many glaciers coalesce (fuse). 10-10,000km2. unconstrained. Larsen Ice shelf
What is thermal regime?
the temperature of the ice
What are the two types of thermal regimes, and what is the difference?
Cold based (polar glaciers) - Glacier is permanently frozen to ground. Average temperature is well bellow 0, surface temperature is -20 to -30. High latitudes.
Warm based (temperate glaciers) - Glacier is not frozen to bedrock. Temperature fluctuates to above melting point, causing meltwater, this is due to the pressure melting point (water melts due to high pressure, even while temperature is below 0 degrees celcius). High altitudes.
Why are glaciers able to move?
Glacial ice can deform
What is pressure melting?
Ice melts at temperature above 0 degrees, due to pressure of overlying ice.
What is the equation for pressure melting?
melting point falls at a rate of 1 degree Celsius for every 100kg/cm3 of pressure
In what thermal regime do glaciers melt. Why?
Warm based glaciers reach pressure melting point at depth. Causing meltwater.
Cold based glaciers do not melt as temperature is far from pressure melting point all thought the glacier.
What is Regelation
Ice melts under pressure, when pressure is relieved water refreezes
Is Basal sliding warm based or cold based?
Warm