41 terms

Chapter 17- Geography (Earth Science)

Glacial and Periglacial Processes and Landforms
Approximately what percentage of the world's freshwater is frozen?
The bulk of ice on Earth is in Greenland and Antarctica.
A general term for a mass of perennial ice, resting on land or floating shelf-like in the sea adjacent to land is _______
Firn has a higher density than glacial ice.
Glacial ice can form during the duration of a single winter season i most glacial areas
Alpine glaciers include all of the following except
an ice cap
A glacier that is confined in a bowl-shaped recess is called a
cirque glacier
A continuous mass of ice covering a large landmass is known as
continental glacier
The type of glacier that dominates Greenland and Antarctica is
ice sheet
in terms of area extent, which of the following sequences is in order from most to least area covered?
ice sheet, ice cap, ice field
Why, specifically, is glacial ice analogous to a metamorphic rock?
It forms as a result of recyrstallization caused by pressure.
Snow that has a compact, granular structure is known as
The transformation of snow into glacial ice in Antarctica takes ________ than in midlatitude alpine glacier's because
longer; less snow falls per year in polar regions and longer;less melting and refreezing occurs in Antarctica
The opposite of the accumulation zone in a glacier is the
ablation zone
The zone where positive gains end and losses begin in the glacial mass balance is called
an equilibrium l ine
Which of the following is true of glacial movement?
The internal flow just below the surface is greater than the basal flow
The presence of melt water at the bottom of glacier can increase its rate of movement.
Which of the following is incorrectly matched?
All of these are correctly matched:
-crevasses--- vertical cracks from friction tension
-ice regelation---- the melting and refreezing of basal ice
-glacial ice---- a metamorphic version of snow and firn
Because the upper regions of a glacier flow ______ than the base of the glacier, the upper part of the glacier tends to be ______.
faster; stretched
Crevasses form in the basal layer of a glacier
Basal slip is facilitated by
-presence of melt water
-saturated sediments
All of the following represent forms of glacial erosion except
Glacial polish results from
Which of the following are erosional landforms created by alpine glaciations?
cols and horns
A tarn is a lake in a
Unlike a stream-cut valley that assumes a characteristic ______- shape, a glacially-carved valley evidences a characteristic ______-shape
V; U
The material in a glacial moraine is
When two valley glaciers join together, they form a ___ at the point at which they merge.
medial moraine
Which of the following is a depositional landform created by glaciations?
Stratified drift
The general term for all glacial deposits is
glacial drift
Unsorted unstratified glacial deposits )not landforms) care called
The material deposited behind a terminal moraine forms a(n) _______, whereas that deposits in front of the terminal moraine forms a(n) ______
Till plain; outwash plain
Kettle holes are formed by
ice that melts after having been buried by glacial sediments
Erractics are
rocks that are not native to an area
Drumlins are formed in _______, and their tapered ends point _______
till plains; downstream
The term periglacial refers to
cold-climate processes along the margins of glaciers
Permanently frozen subsurface ground is called
Areas of permafrost, ground ice, and frost action are in which climate types?
subarctic and tundra
Permafrost develops where soil and rock temperatures are below freezing for at least two years.
The active layer is usually thinner toward the pole and thicker at lower latitude
Unfrozen ground in a region of discontinuous permafrost is known as