Landforms of glaciofluvial deposition - Eskers Flashcards
What are eskers?
Eskers are long, sinuous ridges of coarse sands and gravels deposited by meltwater flowing through subglacial and englacial tunnels parallel to ice flow.
Where are eskers commonly found?
Eskers are commonly found in glaciated lowlands underlain by hard bedrock.
Describe the length and height of eskers?
Eskers vary in size from 1km to 400km long and 20m to 50m high.
Eskers are mainly found at the margins of what type of glaciers?
They are mainly found at the margins of warm based glaciers.
Why do receding glaciers provide suitable conditions for esker formation?
Receding glaciers provide suitable conditions for eskers formation due to their large amounts of sediment load and a high volume of meltwater. Beneath and within the ice, meltwater streams would be highly charged with rock debris.
Why can eskers run both up and down hill?
Due to hydrostatic pressure, eskers can run both up and down hill.
How are eskers formed?
Eskers are formed by the disruption of debris transportation resulting from a decrease in meltwater flow at the end of the summer melt season. The associated sediment blockage within subglacial or englacial tunnels forms ridges which are exposed once the glacier has receded.
In order for an englacial esker to survive, what must glacier ice be?
In order for an englacial esker to survive, glacier ice must be stagnant or receding, otherwise movement of glacier ice would result in the deposited material being reworked.
