Fluvio – glacial landforms
The aims of this booklet are to help you fully understand how Varves, Kames, Eskers, outwash planes, stream
terraces and Kame Terraces form. They are all landforms of fluvio glacial origin.
Read through the booklet and add the locations of each landform to the map of North America below, ensuring that
you record what landform it is and the place name
Kame Deltas
Define what a Kame Delta is;
In the box draw a sketch diagram of the Kame Delta indicated, adding labels to show key relief features
Fully explain how a Kame Delta forms, mentioning sediments, erosion, deposition, rivers discharges and
braiding.
Kame and Kettle topography - Kettle Lakes
A large kettle hole near Dorback Lodge, developed in
thick meltwater deposits and set within a series of
moraine ridges
Describe the shape of the Kettle
hole and its situation
Explain how kettle holes form using the diagrams below. You could use
http://www.fettes.com/Cairngorms/kettle%20hole.htm to help
Kames
Explain how the Kame opposite in Quebec forms. Be
sure to mention that it is supraglacial and deposition.
Outwash Plains (Sandur)
http://en.wikipedia.org/wiki/
Sandur
Use the reference above to
help you with your chart
Outwash plain in Melville peninsular,
Nunavut
The western edge of Skeiðarársandur in
Iceland
Complete the flow chart to explain how Sandur or outwash plains get their characteristic relief and shape. Be sure to mention
the source of sediment, discharge variation, channel braiding, sorting of sediment material, and deposition in your chart.
Glaciers deliver large quantities of unsorted, unstratified and mixed size/shape material to the snout of
the glacier, where it is dumped or deposited as moraine
The end result is a broad, flat relief feature with many braided streams, known as an outwash plain.
Esker
Define and describe what an Esker is
Esker found between lakes in NW Manitoba
Using the diagrams below showing glaciation and post glaciation below, fully annotate that diagram to explain how
subglacial melt water channels can create an Esker. Use the text opposite to help.
The esker (Ir. Eiscir) is one of the most striking landforms of fluvioglacial deposition. In low-lying,
boggy terrain these snaking ridges dominate the terrain, providing vantage points and dry route
ways. On valley floors, the eskers lie within former ice margins marked by moraine systems,
indicating that these ridges form beneath glaciers. Eskers are aligned parallel to former ice flow.
In a valley, an esker will be orientated down-valley and this is one way to distinguish this
landform from any moraine ridges running across the valley floor.
Eskers vary in shape and size. Most are sinuous, with a height of a few to several tens of metres.
The longest continue for several km but most are shorter or discontinuous. Eskers can be broad
and flat-topped, or have a single crest or split into parallel ridges. A beaded esker has broad
hillocks strung out at intervals along its length. Eskers may locally rise up-slope, a clear indication
of water moving under pressure in a pipe-like conduit.
Eskers are usually formed of washed sand and gravel. The free-draining ridges are easily
quarried, making eskers attractive targets for aggregate extraction. The sediments are usually
horizontally- and cross-bedded sands and gravels but vary widely, a reflection of variations in
flow regimes and in sediment supply.
Eskers are casts of sub-glacial tunnels or ice-walled canyons near to an ice margin. Melt water in
glaciers may collect to flow through networks of large tunnels and the water is often highly
charged with debris. Where and when velocity falls then sediment may be laid down on the floor
of the tunnel. If a tunnel becomes blocked by sediment or ice fall then water and sediment is
ponded behind the blockage. If the tunnel is developed on the base of the ice then the
sediments in the esker will be preserved with little disturbance. In contrast, if the tunnel lies
within the ice then the sediments will be considerably disturbed as the ice melts and the thread
of sediment is let down on the valley floor.
Eskers are discontinuous because sedimentation may not take place along the entire length of
the sub-glacial tunnel. Blocks of the overlying ice may fall into the tunnel, later melting to give
kettle-holes along the esker. Alternatively, an esker ridge may become segmented by erosion,
either by meltwater during deglaciation or by the action of post-glacial rivers.
Eskers are predominantly formed at the margin of warm-based glaciers or ice sheets during ice
retreat or stagnation. The accumulation of the esker requires a great deal of sediment and a high
volume of meltwater flow, conditions met as glaciers melt.
Some eskers may also be deposited in channels inside the glacier (englacial), or in ice-walled
trenches on top of it. These sediments are then lowered to the surface upon melting of the
glacier. Sometimes eskers are part of sedimentary fans or deltas at the glacier terminus. Beaded
eskers are deposited in segments, with each segment ending in a bead where a delta formed in a
proglacial lake. Often eskers form only one element in a complex system of ice-marginal
landforms.
Source - http://www.fettes.com/Cairngorms/esker.htm
Meltwater channels
Describe the appearance of the meltwater channel
Explain how meltwater channels are created
Define a Jokulhaup and state how they contribute to the creation of meltwater channels
Review
Annotate the diagram to explain how fluvio-glacial processes can alter glacial landscapes.