These terms are the bare minimum glaciation vocabulary you should be able to use and understand when sitting the examination. You are free to download this page for your own educational use.
- The loss of ice from a glacier due to surface
melting, evaporation and the calving of icebergs.
- The wearing away of rocks by the action of water,
ice or wind using moving debris.
- An arete is a sharp ridge of rock formed by two cirques
meeting back to back. A good example is Striding Edge in the Lake
- The crevasse which forms at the
back of the glacial ice where it meets the cirque
backwall. It is formed as the ice moves down and away from the rock
- Boulder clay
- Glacial moraine consisting of thick
clay with angular rocks. The exact composition will depend on the rocks
eroded by the glacier. Boulder clay is sometimes called till.
- A steep armchair shaped hollow formed by the
erosion of the rock by snow and ice. The rotational movement of the ice
within the cirque hollows out the base creating a depression. The hollow
will become a tarn once the ice retreats.
- See Cirque
- Crag and tail
- An erosional feature produced when ice moved over
a layer of hard rock. The hard rock protected the softer rocks behind it
forming an outcrop with a steep side facing the ice flow and a gentle
slope on the down stream side.
- A vertical crack in the glacial ice. It may be
formed when a glacier begins to move down a steep slope, when it is
forced to make a sharp turn, or when he ice has to move over undulations
in the glacier bed. Crevasses can open and close and vary in their size
and depth. Most are formed across the glacier but where a glacier widens
they may also form parallel to the direction of flow.
- See Cirque
- Elongated oval hills made of Boulder clay.
The long axis is parallel to the flow of the original glacier with the
steeper end facing towards to flow of the ice. They are a depositional
- Large blocks of rock which were picked up by a
glacier then deposited, sometimes hundreds of miles from their
source, when the ice melted.
- A long and narrow ridge of sand and glacial
debris which is raised above the surrounding land. It was once the bed
of a stream that flowed beneath a glacier, and was left behind after the
- Ground moraine
- See Moraine
- Hanging valley
- A hanging valley is a tributary valley that
enters the side of a U shaped glaciated valley. Originally the 'hanging'
valley would have joined the main valley in a normal way, its streams or
rivers flowing into the main valley at the same level. The main valley
was made deeper by glaciation, but the side valleys were left at their
original level. When the ice melted they were no longer level with the
bottom of the valley due to the deepening which had occurred. They
appear to 'hang' on the steep sides of the new valley, their streams
flowing into the main valley via waterfalls.
- Ice sheet
- Vast areas of ice which can cover much of a
continent. A modern example is Antarctica. During Ice Ages these sheets
of ice advanced and covered much of Northern Europe reaching, in the UK, as far
south as Bath.
- Lateral moraine
- See Moraine
- The down slope edge of a cirque
base forms a lip. As the ice rotated in the cirque it moved down at the
back wall and was forced upwards as the glacier began to move out of the
cirque. This creates a lip at the edge due to decreased erosion. See
Cirque for further information.
- Medial moraine
- See Moraine
- The rock material eroded by a glacier is known as
moraine. There are five main types of moraine which you need to
1. Lateral Moraine
: Moraine which forms along the sides of a glacier.
2. Terminal Moraine
: Moraine which collects along the front of a glacier
3. Ground Moraine
: Moraine underneath the glacier.
4. Medial Moraine
: A band of moraine along the centre of the glacier formed when two
glaciers join, their lateral moraines meeting to form the central band
5. Englacial Moraine
: Moraine that is held within the glacier. Usually this is rocks that have fallen into crevasses and become trapped in the ice below the surface.
- Outwash plain
- Material from a terminal moraine washed down
stream may be deposited as an outwash plain.
- An erosional process. Ice freezes to rocks
surrounding the glacier. As the glacier moves the rocks are pulled with
the ice to which they are attached. This results in the pieces of rock
being tugged, or 'plucked' away from the bed and sides of the valley.
- Pyramidal peak
- A pyramid shaped peak formed when cirques develop
all around a mountain. As the cirques erode backwards and meet each
other a very sharp and jagged peak is formed.
- Roches moutonnée
- Translated, this means 'sheep rocks' and gives an
idea of what they look like. The rocks are smooth on the upstream side
and have rough, plucked surfaces on the downstream side. The upstream
surface is often marked with striations.
- The downstream end of a glacier.
- The snowline marks the level on a mountain above
which there is ALWAYS snow. Snow which falls below this line will melt
- These are scratch marks found on rocks which were
eroded by glaciers. When the ice moved over large rocks, the fragments
of rock held in the ice were scraped across the surface scratching it.
The striations are parallel to the direction of ice movement. Striations are a good indication of past glaciation.
- The lake which forms in the hollow at the base of
- Terminal moraine
- See moraine
- See Boulder clay
- Truncated spur
- A river spur cut off by glaciation of a former
river valley. The spur typically has an abrupt and near vertical end.
- U shape valley
- Glacial valleys have a U shape cross section due
to downward erosion across the entire valley floor. By contrast river
valleys have a V shape cross section.
- Valley glacier
- A glacier that originates high up a mountain and
then flows down a valley. This is the usual type of glacier, also known
as an Alpine glacier.