The fluvioglacial landforms needed to be learnt for AS level geography

1. Fluvioglacial landforms
Landforms moulded by glacial
meltwater

2. Outwash plain
Description: This is the area in front of a glacier. It
consists of gravels, sands, and clay (furthest away
from the glacier). They can be 75m deep. An
outwash plain has a gradient of around 2°. There
may be other landforms on the outwashed plain
Formation: Material is deposited by meltwater
streams leaving the glacier. These deposit material
with the largest material deposited first.

3. Varves – Vertical grading of the
outwash plain
Description: A varve is a distinct layer of silt lying on
top of a distinct layer of sand.
Formation: In the summer, there is more meltwater
so heavier material such as sand can be deposited.
In the winter, temperatures are colder so there is
less meltwater. This means that only fine silts can
be deposited. This forms seasonal layers. If the
summer is early, then the layer of sand will be
deeper. If the winter is early, then the layer of silt
will be deeper.

4. Kames
Description: Kames are irregular mounds or
hummocks of sand and gravel on the valley floor.
They are composed of sand and gravels
Formation: They are formed when a surface
river on a glacier runs over a depression in the
ice. This causes a decrease in velocity and
therefore material to be deposited. When the ice
melts, these deposits form kames.

5. Esker
Description: These are long, narrow ridges of
stratified sediment marking the former location on
a glacial tunnel. They are aligned parallel to the
direction of ice flow. They are formed of sands and
gravels and are usually over 10m high and can
stretch for several km, but most are short.
Formation: A glacial tunnel may have water flowing
through it. This water is often filled with debris.
When the velocity drops, the material is deposited.
When the ice melts, the material forms an esker
where the tunnel was.

6. Kettle holes
Description: They are circular lakes on the
outwashed plain. They are usually no more than
2km in diameter, and 10m deep but may be much
larger.
Formation: These are formed when a piece of ice
separates from the main glacier. The blocks of ice
become fully or partially covered by material on the
outwash plain. When the ice melts, a deep hollow is
left. They may then fill with water, making a kettle
lake.