| Geomorphology | ||||||||||||||||||||||||||||||
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Glaciers
Glaciers are slow moving flows of ice found on mountains and in cold climates. This is a photograph of the foot of the glacier. Notice the dark lines of till running parallel in the ice called medial moraines. |
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Permafrost
The ground is permanently below zero degrees. An active layer on the surface of permafrost defrosts in the summer seasons allowing plant growth to occur. The northern coast of the Yukon Territory is an area of subsea permafrost. |
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Moraines
Sediment deposits on the edges or inbetween the glacier. Lateral moraines as in the picture are formed by the push of the ice as it erodes the mountains around it. Rocks from the slopes roll down to the glacier and pile up forming these lateral ridges. |
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Kettle Lakes
Small lakes form after the ice retreats. Some are formed when large ice bergs are left to melt on the surface eroding a depression. The water is not able to drain or is replenished by means of precipitation and kettle lakes are a result. |
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Eskers
As the glacier melts, water carrying sediments flows into the nearest body of water. The sediments within the meltwater forms a tunnel around the stream formed. After the glacier has retreated linear features called eskers are left. |
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Striations
Scratches are produced from the weight and thick icesheets on large rock surfaces as shown in the photo. These lines help indicate which direction the ice was moving, narrowing it down to two lateral motions. In the thumbnail multiple striations are shown indicating the ice had passed over the rock more than once in different directions. |
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Glacial Till
The ice moves across the earth's surface plucking, scratching, and scraping the land. Rock fragments of uneven sizes results. Glacial till is poorly sorted and sediments also have rough edges unless it has been reworked by glacial meltwater. |
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Frost Heaving
Frost heaving occurs when water gets into cracks beneath the earths surface. This water will freeze and as water freezes it expands. The soil will be stretched until it can no longer withstand the pressure. The earth is raised and cracks. |
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Hoodoos
These dramatic features are sedimentary rocks left from past landscapes. Wind and rain erode the soft sedimentary layers leaving behind the less vulnerable sediments behind. |
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Drumlin
Ice scrapes the earths surface as it moves and often imperfections on the surface cause the ice to deposit sediments around the obstructions. This leaves a trail marked by a drumlin. The gentle sloping side of the hill is called the tail and this points in the direction of the ice movement. |
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Gullies
These dramatic features are sedimentary rocks left from past landscapes. Wind and rain erode the soft sedimentary layers leaving behind the less vulnerable sediments behind. Over time minerals within the sediment leaches down and forms accumulation layers. These bands are formed by the movement of minerals; the bottom layers are darker and are the accumulation layers. |
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Ice wedging
A process common in the arctic is that water gets into crevases in the ground and and rocks. This water freezes and expands as a result pushing the rock apart |
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Pingos
These strange cone shaped features are formed by water freezing beneath the ground. As the water freezed the earth is forced to expand and when the earth weakens the surface begins to crack. It is still unknown where the large source of water originates large enought to supply the ice to grow beneath the surface. |
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