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56 Cards in this Set
- Front
- Back
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What is a glacier?
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Any body of flowing ice that has been formed on land by compaction and re-crystallization of ice.
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What are 2 types of glaciers?
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1.) Continental
2.) Alpine or Mountain |
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Where do the only 2 continental ice sheets exist today?
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1.) Greenland
2.) Antarctica |
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What are alpine or mountain glaciers?
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Small, found in high elevations where a lot of snow falls and can remain most of the year.
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What are the 3 types of alpine glaciers?
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1.) Cirque glacier
2.) Valley glacier 3.) Piedmont glacier |
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What is a cirque glacier?
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Found near the top of the mountains and on the side; Craves out a bowl-like depression in the side of the mountain.
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What is a valley glacier?
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Extends down the mountains from the cirque glacier down the mountain.
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What is a piedmont glacier?
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Extends from the valley glacier into the area around the mountain.
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What are glaciers composed of?
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Of ice that originally fell as snow and then the snow becomes compacted and the air is gradually forced out. The material is then no longer snow, it becomes more dense, and it becomes glacier ice.
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What are 2 types of partially compacted snow?
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1.) Neve
2.) Firn |
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What is neve snow?
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All compacted snow, a transition between snow and glacial ice.
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What is firn snow?
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A specific term for neve that doesn't melt.
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What is glacial ice?
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Dense ice that is deep blue in color and is very heavy.
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How long does it take to change snow to firn to glacial ice?
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25 to 100 years.
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What is the ablation zone?
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The zone of melting on a glacier.
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What is the accumulation zone?
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The zone of non-melting snow on a glacier; The region where snow is added to a glacier.
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What is the area in mountain glaciers called Bergschrund?
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The crack between the glacier and the mountains; Dangerous and it is often covered by a thin layer of snow.
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What is the area in mountain glaciers called Crevasses?
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An area where elevation suddenly drops and ice breaks into deep crevasses and ice falls; They often can be covered with a thin cover of snow.
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Are glaciers safe places?
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NO THEY ARE NOT SAFE UNLESS YOU KNOW WHAT YOU ARE DOING!!!
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Why do glaciers move?
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Because the weight of the ice and gravity pull them down the mountain or across the land.
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Which part of a glacier moves the fastest and why?
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The center because the sides and bottom of a glacier are sliding against rock and therefore friction slows down those parts of a glacier down.
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What are the 2 methods of glacial erosion?
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1.) Glacial Abrasion
2.) Glacial Plucking |
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What is the method of glacial abrasion?
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As rock and ice carried by glacier, they scrape and grind against surrounding rock and wear it away.
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What is the method of glacial plucking?
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Glacier forces rock fragments to be lifted out of surrounding rock by freezing water in cracks and surrounding rock. Cracks expand and the rock fragment "pops" out of the surrounding rock and is carried down the mountain by the ice!
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What is moraine and what does it appear to be?
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Debris carried and deposited by glaciers; Often appears as small hills or ridges after glacier has melted away.
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What are the 3 types of alpine (mountain) moraines?
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1.) Lateral
2.) Medial 3.) Terminal |
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What is a lateral moraine?
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Material carried and deposited by glaciers on SIDES OF GLACIER.
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What is medial moraine?
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Debris created by 2 LATERAL MORAINES merging; the debris is located in MIDDLE of a new glacier.
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What is terminal moraine?
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Debris is pushed and left IN FRONT OF the glacier.
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What is an Arete?
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Formed when 2 cirque glaciers on opposite sides of mountain cut away the mountains, leaving a SHARP RIDGE between the two cirques.
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What is a horn?
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When 3 or more cirques intersect (or 3 or more aretes intersect).
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What is the best example of a horn?
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Switzerland in the Alps: The Matterhorn.
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What is a glacial trough?
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A huge "U"-shaped valley carved by a glacier.
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What is a Fjord?
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When a glacial trough fills with sea water.
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What is an example of glacial troughs and fjords?
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Norway
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What is the comparison of glacial troughs and river valleys?
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A river valley tends to be "V"-shaped while a glacial trough tends to cut a "U"-shaped valley.
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What is a tarn lake?
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When a cirque glacier melts, it generally leaves a small lake in the cirque depression.
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What happens to the land when its under 3000-4000 meters of ice?
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The land sinks!!
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What is Isostatic Depression?
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The weight of ice is so great that the land is depressed sometimes to the point of being BELOW sea level.
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What is an example of isostatic depression?
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Hudson Bay in Canada.
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What is an ice shelf?
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A large plate of moving ice that has slid out on top of the ocean; Can be very thick.
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What is an example of an ice shelf?
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Ross Ice Shelf in Antarctica.
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What is sea ice?
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Ice formed directly on ocean by freezing ocean water; Not very thick.
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What is an iceberg?
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Formed by pieces breaking off continental glaciers and falling into the ocean.
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What is calving?
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The process by which icebergs break off from an ice shelf.
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Where can you find icebergs?
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Around Greenland, Antarctica, and a few small glaciers around oceans.
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What is a meltwater stream?
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A river created by water from melting ice from a glacier.
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What do meltwater streams carry and what do they tend to be?
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Carry lots of sediments and tend to be braided streams with sandbars located in the middle of the river.
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What is till?
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Rubble and debris carried ahead of glaciers.
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What is a kettle lake?
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A shallow, sediment-filled body of water formed by retreating glaciers or draining flood waters.
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When a glacier starts to melt, where does it start and why?
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Underneath of the glacier first because of the pressure.
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How is melted glacier water carried out of the glacier?
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Through tunnels in the glacier (ice caves).
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What is a Esker?
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When the glacier is completely melted, the meltwater river dries up and all that is left is a long, meandering ridge of rock and rubble which looks like a river of rock and that ridge is a esker.
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What is a drumlin?
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A hill that resembles an upside-down spoon.
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What does drumlin consist of?
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Glacial till
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Where are drumlins found?
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Behind the terminal moraine.
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