Glaciers

Depositional Features

• Glaciers create distinct landforms including moraines, drumlins, eskers, and kettles.

Moraines

• Definition: Deposits of poorly sorted sediment (till) at glacier edges and sometimes in their center.

• Types:

  • End (Terminal) Moraine: Dropped at the glacier's front.

  • Lateral Moraine: Found at the sides of glaciers.

  • Medial Moraine: Formed by the merger of two lateral moraines.

Glacial Till

• Definition: Poorly sorted materials ranging from boulders to clay, transported and deposited by glaciers.

• Formation Processes:

  1. Till conveyed off the glacier's top.

  2. Till pushed through the glacier and deposited at the front.

  3. Till left after a glacier melts.

Erratics and Drumlins

• Glacial Erratics: Large boulders left behind, significant in continental glaciers.

• Drumlins: Streamlined hills formed from glacial till, indicating ice flow direction.

Eskers and Kettles

• Esker: Ridge formed from sediment deposited in a tunnel under a glacier.

• Kettle: Depression left by melted ice block, can form kettle lakes.

Erosional Features

• Erosion Types: Glacial abrasion leads to scrapes and striations on bedrock. Significant in both continental and valley glaciers.

• Valley Landforms: Include cirques, horns, tarns, U-shaped valleys, and hanging valleys.

Valley Shapes

• U-Shaped Valleys: Created by glacial erosion versus V-shaped valleys created by river erosion.

Summary of Common Mountain Valley Glacial Features

• Key features include cirques, horns, arêtes, kettle lakes, drumlins, and various moraine types.