Landforms of glacio-fluvial deposition

Question 1

Formation of a kame

Answer 1

A kame is a hill or hummock composed of stratified sand and gravel laid down by the glacial meltwater; there are two types of kames:
1. Delta kame –> some of these are formed by en-glacial streams emerging at the snout of the glacier, which lose energy at the base of the glacier and deposit their load; others are the result of supra-glacial streams depositing material on entering ice-marginal lakes, losing energy as they enter the static body of water

2. Kame terrace –> these are ridges of material running along the edge of the valley floor; supraglacial streams on the edge of the glacier pick up and carry lateral moraine which is later deposited on the valley floor as the glacier retreats
   - the streams form due to the melting of ice warmed in contact with the valley sides as a result of friction and the heat-retaining properties of the valley-side slopes

Although they may look similar to lateral moraines, unlike them, they are composed of glacio-fluvial deposits which are more rounded and sorted

Question 2

Formation of eskers

Answer 2

An esker is a long, sinuous ridge composed of stratified sand and gravel laid down by glacial meltwater - material is deposited in subglacial tunnels as the supply of meltwater decreases at the end of the glacial period

Subglacial streams may carry huge amounts of debris under pressure confined tunnels at the base of the glacier
- as the glacier retreats, the point of deposition will gradually move backwards

Question 3

Formation of outwash plains

Answer 3

An outwash plain (sandhur) is a flat expanse of sediment in the pro-glacial area –> as meltwater streams gradually lose energy as they enter lowland areas beyond the ice front, they deposit their load

The largest material is deposited nearest the ice front and the finest material is deposited further away
- outwash plains are typically drained by braided streams, which are river channels subdivided by numerous islets and channels