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Nivation, Transportation and Deposition - Coggle Diagram
Nivation, Transportation and Deposition
Nivation
Combination of freeze-thaw weathering, solifluction, transport by running water and chemical weathering.
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Transportation
Moving ice is capable of carrying huge amounts of debris. This material can come from a range of sources.
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Debris Flows - in areas of high precipitation and occasional warmer periods, melting snow can combine with scree, soil and mud.
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Deposition
Glaciers deposit their load when capacity to transport material is reduced. Normally occurs due to ablation in period of glacial retreat.
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All material deposited is known as drift. Till is material deposited directly onto ice. Outwash is material deposited into meltwater.
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Position
Supraglacial Debris - carried on the surface of the glacier. Often comes from weathering and rockfall.
Englacial Debris - within the ice. Could've been supraglacial debris that has been covered in snow, fallen into crevasses or sunk into ice due to localised pressure melting.
Subglacial Debris - embedded at the base of the glacier, may have been derived from plucking or abrasion.
Types of Till
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Till is generally angular in shape as it has not been embedded in the ice and has not been subjected to further erosion.
It is unsorted as everything is deposited together. When water deposits material, it progressively loses energy and deposits material in a size-based sequence.
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