Fluvioglacial processes Flashcards
What is an outwash plain?
Outwash plains occur in front of melting glaciers. They are expansive, generally flat areas that are dominated by braided rivers when the glacier is actively melting.
What are the processes of water movement in the glacial system?
Supraglacial flow
Englacial flow
Sub-glacial flow
What are the characteristics of glacial and fluvioglacial deposits?
Stratification (sorted by meltwater in layers)
Sorting
Imbrication (overlapping of successive layers of sediment)
Grading
Supraglacial flow
Surface water flow
Englacial flow
The body of the glacier, between the surface and the glacier bed
Sub-glacial flow
a system of tunnels and interlinked cavities and conduits, with water flowing under extreme pressures from the ice above
Flow is determined by pressure gradient and topography.
Fluvioglacial landforms
Eskers
Kames (knobs)
Kame Terraces
Kettle Holes
Proglacial lakes
Subglacial lakes
Drumlins
Varves
Braided Streams
How are Braided streams formed?
When a central sediment bar begins to form in a channel due to reduced streamflow or an increase in sediment load.
The central bar causes water to flow into the two smaller cross sections on either side.
The smaller cross section results in a higher velocity flow.
How are kames formed?
A glacier melts and meltwater streams carry material from within and under the glacier to be deposited immediately in front of the glacier into meltwater lakes
How are kettle holes formed?
When buried ice melts and overlying sediment collapses, creating something of circular pools of meltwater
How are Proglacial lakes formed?
Meltwater dammed by a terminal moraine, found in front of the solid glacier.
