Fluvioglacial Processes

Question 1

Define Fluvioglacial Processes

Answer 1

Processes that involve the action of glacial meltwater

Question 2

Define Fluvioglacial Landforms

Answer 2

Landforms that result from erosion or deposition, due to glacial meltwater

Question 3

Explain how glacial meltwater creates meltwater channels by EROSION

Answer 3

1. ) When glacial ice melts due to retreating glaciers, streams of meltwater is produced.
2. ) Surface meltwater filters through gaps (e.g. crevasses) in the glacier and flows through underneath the the glacier, before running through the snout of the glacier
3. ) But they can also be supraglacial flows (flow at surface), or englacial (within glacier) or subglacial (underneath glacier),
4. ) Subglacial streams can flow uphill due to hydrostatic pressure : pressure that a fluid exerts, due confined areas.
5. ) Meltwater flows that are under glacier (subglacial), can result in Nye Channels. These are channels that are cut downwards into the bedrock by headward erosion
6. ) Meltwater streams cause erosion, in the same way as normal rivers through hydraulic action and abrasion

But they cause more erosion than river, as the pressure of ice means they carry more material eroding the landscape

7. ) Meltwater streams form deep troughs called meltwater channels. Due to erosive power of water, the channels are deep and wide
8. ) With high discharge, large meltwater water channels create sub - glacial valleys that are often deep and contain potholes. Stones and gravel carried by glacial meltwater began to grind holes grind holes into bedrock
9. ) After the glacier retreats, the deep meltwater channels are left with very shallow streams running through them

Question 4

Explain Formation of Outwash Plain

Answer 4

. Outwash plains are found in front of the glacier’s snout and are deposited by meltwater streams from glacial ice

. Consists of material brought down by the glacier.

. The heaviest coarser material travel the shortest distance and is found next to the glacier; The finest material such as clay is deposited some distance from the plain before being deposited

. Deposits are layered vertically, reflecting the seasonal flow of meltwater streams

. Series of depressions (KETTLEHOLES) filled with lakes are found on outwash plain

. They are formed when blocks of ice washed onto the plain leave a gap in the sediments, due to erosion.

Question 5

Explain Formation of an esker

Answer 5

. Eskers are layered ridges of material running in the direction of the glacier

. Contains coarse material such as sand and gravel

. Deposits made by sub - glacial streams. The channel of the stream will be restricted by ice wall, meaning there will be hydrostatic pressure enabling large load to be carried and allowing the stream to flow uphill. This creates the esker shape

. A ridge will be left when the glacier retreats during deglaciation