Grade 9 Geography Unit 3

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.