Grade 9 Geography – Strand 3
Glaciation Definitions
Term
Definition
Arête
A thin, almost knife-like, ridge of rock which is typically formed
when two glaciers erode parallel U-shaped valleys. The arête is
the thin ridge of rocks remaining after glaciation.
Alpine Glacier
Glacier occupying one or more valleys in an alpine region. Glacier movement is
downward from high elevations to low elevations under the force of gravity
Cirque
An amphitheatre-like valley, or valley head, formed by
erosion at the head of a glacier. To make this formation,
the glacier has a rotational slide that abrades the floor of
the basin BUT not the edges. This process causes a bowl
shape to form.
Continental Glacier
Glacier that spread out to cover a large area. Glacier movement is by their own
weight.
Drumlin
Geologic feature formed by ice sheets. An “egg-shaped” hill with a steep side at
the wide end and a gentle slope on the other side
Erratic
Rock picked up by ice, carried along and deposited
many kilometres away. It is easily identifiable
because the rock composition is different from the
bedrock in the region in which the rock was
deposited. An erratic change range in size from
pebbles to large boulders.
Esker
A long ridge of material deposited by a melt water stream
flowing from beneath a glacier. Esker are like railroad
embankments
Horned Peak
When a cirque erodes leaving only a sharp peak flanked by
nearly vertical headwall cliffs. The most famous horned peak
is the Matterhorn in Switzerland.
Lake Plain
Fertile bottom of an ancient glacier lake. Now, the land is typically highly sought
for agriculture.
Moraine
Unconsolidated debris or material deposited by a glacier, often in the form of
hills. For example, a terminal moraine is formed at the farthest point reached by
a glacier.
Spillway
A deep valley created by large volumes of water flowing from a melting
Continental Glacier. Once the ice sheet melted, the spillway became the path for
a small stream called MISFIT STREAM.
Striation
In glaciation, a groove often gouged out in the bedrock under
the ice sheet by rocks frozen in the ice.
Till Plain
Flat to gentle hilly area created by glacial deposition.