3.3 UPLAND GLACIAL LANDFORMS (formed by erosion)
You should be able to recognise the following
landforms on maps or diagrams, describe them, explain how they
were formed and be aware of their economic consequences.
Diagram 1.4c shows a number of upland glacial landforms (erosion
and deposition). You must be able to identify these features
on diagrams.
Diagram 3.3a Upland glacial landforms
tip!
shade the water features blue.
shade the scree orange
shade the alluvial fans yellow
shade the moraine features brown
corrie
description - This is a steep sided hollow at the head
of a glaciated valley. It is often described as an 'armchair'
shaped hollow. We often find a small loch (lochan) in a corrie.
explanation - At the start of a period of glaciation we
would find that some snow which fell on a mountainside, in small
north - facing hollows, may not all melt during the following
summer.
Over a number of years as more and more layers of snow build
up, then the lowest layers would be compacted and turn to ice.
Eventually, as this ice continues to build up, it starts to move
down slope under the force of gravity and so a glacier is born.
diagram - Annotate the following diagrams
to show :-
scree slope
wearing away of rock by ice and rock fragments
loch in the deep floor of the corrie
steep rocky back of the corrie
raised rocky 'lip' at the 'mouth' of the corrie
arete
description - This is a sharp ridge on the mountainside.
explanation - An arete is formed where two corries 'eat'
into a mountainside leaving a sharp ^ - shaped ridge.
diagram - Examine Diagram 3.3a then draw a your own diagram
of an arete in the space below.
horn
description - This feature is a sharp pointed steep-sided
summit. It is often called a pyramidal peak (eg the Matterhorn).
explanation - Horns are formed where three or more corries
cut back into a mountain.
diagram - Examine Diagram 3.3a then draw your own diagram
of a horn in the space below.
u-shaped valley
description - This is a valley whose
typical cross section is shaped like a 'u'.
explanation - A glacier is much bigger and more powerful
than a river and so glaciers deepen and widen the v-shaped valleys
formed by rivers in mountain areas. These glacial formed valleys
have flat bottoms and steep sides and are called u-shaped valleys.
As ice is not so flexible at turning corners, so the former spurs
(ridges of high land see Diagram 3.3a) are truncated (cut off)
straightening the former v-shaped valleys.
If a u-shaped valley is at the coast and it is flooded by the
sea, then it is known as a fjiord.
diagram - Examine Diagram 3.3a
hanging valley
description - This is a smaller u-shaped valley 'perched'
on the mountainside above the main u-shaped valley.
explanation - Where a tributary glacier was much smaller
than the main valley glacier, it would be much less able to erode
the landscape and so its valley would not be as wide or deep.
diagram - Examine Diagram 3.3a.
truncated spur
description - This is a steep cliff of bare rock on the
valley side.
explanation - This feature is formed by the ice cutting
the end off of spurs as the ice is much less flexible the streams
which formerly flowed down the valley.
diagram - Examine Diagram 3.3a.
erratic
description - This is a large boulder. These can range
in size from the size of a washing machine upwards.
explanation - This boulder has been transported by ice
from its source area and deposited when the ice melted or was
no longer able to transport it.
diagram - This is usually shown as a large boulder perched
on the mountainside.
roche moutonne
description - This is a mound of rock on the floor of
a u-shaped valley. One end of this feature is smooth whilst the
other is rugged.
explanation - This feature is formed where ice passes
over a hard band of rock. This rock is abraded to form a smooth
slope at the end the ice arrives at first and plucked to leave
a rugged surface at the other end.
diagram - Examine Diagram 3.3a and the sketch below
