geography exam 4 chapter 18
The Arctic is warming about how many times faster than the rest of the world?
2
What percentage of soils in the Northern Hemisphere are permafrost soils?
25%
Scientists think that northern permafrost could release up to about __________ billion metric tons of carbon to the atmosphere by 2100.
500
During the last glacial maximum, sea levels were __________ meters lower than today.
85
_________ is a large mass of ice that is formed from the accumulation of snow.
A glacier
In late July 2012, what happened on Greenland that had never been witnessed before?
Almost all the surface layer of the ice sheet melted.
What factor do scientists think is causing some of Antarctica's outlet glaciers to flow into the ocean faster?
As ice shelves break apart, their buttressing effects are removed.
_________ occurs where permafrost is 100 meters thick or more.
Continuous permafrost
How does the active layer respond to atmospheric warming?
It deepens.
What happened to the Larsen B ice shelf in 2002 that surprised scientists?
It disintegrated.
_________ are mounded accumulations of glaciofluvial sediments deposited by an ice sheet.
Kames
_________ is ground that has been influenced by freeze-thaw cycles that slowly wedge soil apart.
Patterned ground
What factor do scientists think is causing some of Greenland's outlet glaciers to flow into the ocean faster?
The glaciers are being lubricated by liquid water from moulins.
________ is any debris deposited by a glacier without the influence of running water.
Till
The process in which the movement of one material wears away another material is called _____
abrasion
When the mass balance of a glacier is positive, the toe's position will ______
advance
A(n) __________ is a steep-sided sharp ridge.
arête
The fastest flow in a glacier occurs where?
at the surface and center of the glacier
Proglacial lakes are found where?
at the toe of a glacier
In the __________ zone, ice cracks and breaks and forms crevasses.
brittle
Global sea levels were lower over 10,000 years ago due to what?
building of continental ice sheets
A(n) __________ is a bowl-shaped depression with steep headwalls.
cirque
What type of glacier forms a bowl-shaped depression?
cirque glacier
A low area or pass over a ridge formed by two cirque glaciers is called a(n) ____
col
Which glacial landform is an elongated hill composed of till?
drumlin
When trees become tilted as the active layer deepens during summer, a __________ results.
drunken forest
The elevation at which snowfall accumulation and snowmelt are equal is called the _______
equilibrium line
Which glacial landform is an elongated ridge composed of sorted sand and gravel that was deposited by a subglacial stream?
esker
A drowned glacial valley is called a ________
fjord
What type of glacier forms a large dome over high mountain regions?
ice cap
An __________ is the portion of an ice sheet or an outlet glacier that extends over the ocean.
ice shelf
An __________ is a large block of ice that breaks from the toe of a glacier or an ice shelf and floats in the ocean or a lake.
iceberg
Which is not related to the current loss of ice on Greenland?
increased precipitation
Which is a depression formed by a buried stagnant ice block?
kettle hole
Which type of moraine forms along the edge of a glacier?
lateral moraine
Where two glaciers merge, their lateral moraines also merge, forming a __________ moraine.
medial
Which is not a significant factor causing sea-level rise?
melting ice shelves
What is a heap of unsorted sediments deposited by a glacier called?
moraine
The Northern Hemisphere's thickest permafrost is found in ______
northeastern Russia
When the mass balance of a glacier is neutral, the toe's position will _______
not change
One of a series of small lakes that form in a glacial valley is called a _____
paternoster lake
What type of glacier forms lobes of ice that spill out onto flat plains?
piedmont glacier
A __________ is a hill with a core of ice.
pingo
In the __________ zone, ice deforms and flows in a glacier.
plastic deformation
The process in which a glacier pulls up and breaks off pieces of bedrock as it moves downslope is called __________.
plucking
Atmospheric warming will do what to the elevation of the equilibrium line?
raise it
A __________ moraine forms where the toe of the glacier pauses as it is gradually retreating upslope.
recessional
When the mass balance of a glacier is negative, the toe's position will _________
retreat
What is the name for an elongated and asymmetrical ridge of glacially carved bedrock?
roche moutonnée
Which is not used by scientists to monitor changes in glacier mass balance?
seismometers
Streams that flow beneath a glacier and exit from its toe are called what?
subglacial streams
Unfrozen areas in an area dominated by permafrost are called ______
talik
A lake that forms within or just below a cirque is called a(n) _____
tarn
__________ moraine marks the farthest advance of the glacier's toe before it begins retreating upslope.
terminal
The surface of permafrost that thaws each summer and freezes in fall is called _____
the active layer
The terminus of a glacier is the _______
toe
The __________ zone is found about 60 meters below the glacier's surface.
transition
What type of glacier occupies mountain valleys?
valley glacier
The __________ is the area of a glacier where ice loss exceeds ice accumulation.
zone of ablation
The __________ is the area of a glacier where ice gain from snowfall exceeds ice loss.
zone of accumulation