Is a closed depression formed by melting of an ice block buried in a moraine or outwash plain?
The ice becomes buried in the sediment and when the ice melts, a depression is left called a kettle hole, creating a dimpled appearance on the outwash plain. Lakes often fill these kettles; these are called kettle hole lakes. Another source is the sudden drainage of an ice-dammed lake.
What is the name used for cracks in the upper portion of a glacier?
A crevasse is simply a deep crack in a glacier or ice sheet. Crevasses pose dangers to hikers and mountain climbers. A crevasse is a deep, wedge-shaped opening in a moving mass of ice called a glacier. Crevasses usually form in the top 50 meters (160 feet) of a glacier, where the ice is brittle.
What is one of the two major flow mechanisms in a glacier?
There are two primary mechanisms at work within a glacier that cause it to move: plastic flow and basal slip.
Which of the following is an erosional feature produced by valley Alpine glaciers?
Alpine glaciers produce wide valleys with relatively flat bottoms and steep sides due to the erosion that occurs at the base and edges of the glaciers. These are known as U-shaped valleys (Figure 17.17).
What are breaks in glaciers called?
Calving is when chunks of ice break off at the terminus, or end, of a glacier. Ice breaks because the forward motion of a glacier makes the terminus unstable. We call these resulting chunks of ice “icebergs.”
What name is used to describe the part of the glacier where losses of ice exceed the accumulation of new snow and ice?
Retreat. A decrease in the length of a glacier compared to a previous point in time. As ice in a glacier is always moving forward, its terminus retreats when more ice is lost at the terminus to melting and/or calving than reaches the terminus.
What is Crevice and crevasse?
'Crevice' and 'Crevasse': A Gap in Meaning. Look before you leap. Crevice and crevasse are very similar words: they both derive from the Old French crever, a verb meaning "to break or burst," and both refer to an opening of some kind.
What are ice fissures?
When ice fissures, as with the human body, it is indicative of stress and strain. With ice, the resultant crack or crevasse marks its presence on a glacier or ice sheet. The cause of the fissure is usually movement within the ice body, which then unleashes shearing stress. Fissuring refers to both process and outcome.
What term describes the straight scratches on rock surfaces created by glacial abrasion?
10,000 years ago. Straight scratches on rock surfaces created by glacial abrasion are known as: a. rock flour.
What is it called when a glacier moves?
Glacial motion is the motion of glaciers, which can be likened to of rivers of ice. It has played an important role in sculpting many landscapes. Most lakes in the world occupy basins scoured out by glaciers.
What is glacier abrasion?
Abrasion: The ice at the bottom of a glacier is not clean but usually has bits of rock, sediment, and debris. It is rough, like sandpaper. As a glacier flows downslope, it drags the rock, sediment, and debris in its basal ice over the bedrock beneath it, grinding it.
What is a sharp ridge of ice on the surface of a glacier?
Nunatak. A mountain peak or ridge that pokes through the surface of an Ice Field or a Glacier. It may separate adjacent Valley Glaciers (Greenlandic).
Why is it called calving?
Calving of ice shelves is usually preceded by a rift. These events are not often observed. Etymologically, calving is cognatic to when the verb is also used to mean "to give birth to a calf."
Which term refers to the large piece of ice that breaks off from the front of a glacier and enters the sea?
calving. large pieces of ice break off the front of the glacier; creates icebergs in places where the glacier has reached the sea or a lake. icebergs.
What is accumulation and ablation?
A glacier is a pile of snow and ice. In cold regions (either towards the poles or at high altitudes), more snow falls (accumulates) than melts (ablates) in the summer season.
What is ablation in geography?
(1) combined processes (such as sublimation, fusion or melting, evaporation) which remove snow or ice from the surface of a glacier or from a snow-field; also used to express the quantity lost by these processes (2) reduction of the water equivalent of a snow cover by melting, evaporation, wind and avalanches.
What is a crevasse in a glacier?
Crevasses are cracks that form in glacier ice when the glacier is put under too much stress for it to deform by flowing.
What is a fissure called?
1 : a narrow opening or crack of considerable length and depth usually occurring from some breaking or parting a fissure in the earth's crust. 2a : a natural cleft between body parts or in the substance of an organ.
What does fissure mean in geography?
In geology, a fissure is a fracture or crack in rock along which there is a distinct separation; fissures are often filled with mineral-bearing materials. On volcanoes, a fissure is an elongate fracture or crack at the surface from which lava erupts.
What term means scratches in rocks caused by glaciers?
Glacial striations or striae are scratches or gouges cut into bedrock by glacial abrasion. These scratches and gouges were first recognized as the result of a moving glacier in the late 18th century when Swiss alpinists first associated them with moving glaciers.
What is a piece of ice that breaks off a glacier and floats away called?
Icebergs are large chunks of ice that break off from glaciers. This process is called calving. Icebergs float in the ocean, but are made of frozen freshwater, not saltwater. Most icebergs in the Northern Hemisphere break off from glaciers in Greenland.
What is it called when a glacier melts?
Ablation. The loss of ice and snow from a glacier system. This occurs through a variety of processes including melting and runoff, sublimation, evaporation, calving, and wind transportation of snow out of a glacier basin.
What is abrasion and attrition?
Abrasion occurs as a result of two surfaces rubbing against each other resulting in the wearing down of one or both of the surfaces. However, attrition refers to the breaking off of particles (erosion) which occurs as a result of objects hitting against each other.
What is abrasion and Corrasion?
abrasion (corrasion) The erosive (see EROSION) action that occurs when rock particles of varying size are dragged over or hurled against a surface. Some common agents of abrasion are the bed load of streams, rock debris embedded in the bases of glaciers, and sand and shingle transported by wind or waves.
What is a horn or pyramidal peak?
A pyramidal peak, sometimes called a glacial horn in extreme cases, is an angular, sharply pointed mountain peak which results from the cirque erosion due to multiple glaciers diverging from a central point. Pyramidal peaks are often examples of nunataks.
How do you spell calves on your leg?
Calves is the plural form of the word calf, which refers either to a baby animal or to a section of the leg below the knee.
- Calves is the only correct spelling of this word.
- Calfs is an incorrect spelling of this word, and is to be avoided.
Which term refers to the large piece of ice that breaks off from the front of a glacier and enters the sea quizlet?
calving. large pieces of ice break off the front of the glacier; creates icebergs in places where the glacier has reached the sea or a lake. icebergs.
What is abrasion glacier?
Abrasion: The ice at the bottom of a glacier is not clean but usually has bits of rock, sediment, and debris. It is rough, like sandpaper. As a glacier flows downslope, it drags the rock, sediment, and debris in its basal ice over the bedrock beneath it, grinding it.
What is sublimation glacier?
Introduction. Snow sublimation is a loss of water from the snowpack to the atmosphere due to the direct phase transition of snow to water vapor. Sublimation can occur from a static snow surface, and is enhanced under drifting and blowing snow conditions.
What is the glacial snowline?
The snowline is the line (as in a point of elevation on a mountain) at which the amount of snow falling equals the amount of snow melting in the summer. If the climate cools enough, so that snowlines are lowered, glaciers develop in mountains, and ice sheets will develop in mid-latitudes.