Erosional and depositional features of landforms formed by glaciers.
Best of luck.
Erosional Landforms
Striations
Glacial striations or glacial grooves are scratches or gouges cut into bedrock by process of glacial abrasion. Glacial striations usually occur as multiple straight, parallel grooves representing the movement of the sediment-loaded base of the glacier.
Given a glacial striation at Mt. Rainier
Cirques
A cirque is an amphitheatre-like valley head, formed at the head of a valley glacier by erosion.
Given two cirques.
Glacial Horns
A glacial horn, is a mountaintop that has been modified by the action of ice during glaciation and frost weathering
. Given a classic glacial horn
Arêtes
An arête is a thin, almost knife-like, ridge of rock which is typically formed when two glaciers erode parallel U-shaped valleys. The arête is a thin ridge of rock that is left separating the two valleys. Arêtes can also form when two glacial cirques erode headwards towards one another, although frequently this results in a saddle-shaped pass.
Given above a glacial arete
Trim Lines
A trim line, is a clear line on the side of a valley formed by a glacier. The line marks the most recent highest extent of the glacier.
Given a trim line
Hanging Valley
A hanging valley is a tributary valley with the floor at a higher relief than the main channel into which it flows. They are most commonly associated with U-shaped valleys when a tributary glacier flows into a glacier of larger volume.
Given Bridal Veil Falls in Yosemite National Park flowing from a hanging valley.
Depositional Landforms
When the glaciers retreated leaving behind their freight of crushed rock and sand, they created characteristic depositional landforms. Examples include glacial moraines and eskers. Drumlins and ribbed moraines are also landforms left behind by retreating glaciers.
Glacial Moraines
A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have fallen off the valley walls as a result of frost wedging or landslide. Moraines may be composed of debris ranging in size from silt-sized glacial flour to large boulders. The debris is typically sub-angular to rounded in shape. Moraines may be on the glacier’s surface or deposited as piles or sheets of debris where the glacier has melted. Moraines may also occur when glacier- or iceberg-transported rocks fall into a body of water as the ice melts.
Given a picture of a lateral moraine.
Eskers
An esker is a long winding ridge of stratified sand and gravel. Eskers are frequently several kilometres long and, because of their peculiar uniform shape, are somewhat like railroad embankments.
Given a picture of an esker.
Drumlins
A drumlin is an elongated whale-shaped hill formed by glacial ice acting on underlying unconsolidated till or ground moraine.
Given a picture of esker, drumlin and moraines.
Best of luck.
As the glaciers expanded, due to their accumulating weight of snow and ice , they crushed and scoured surface rocks and bedrock. The resulting erosional landforms include striations, cirques, glacial horns, arêtes, trim lines, U-shaped valleys, and hanging valleys.
- Cirque: Starting location for mountain glaciers
- U-shaped valley: U-shaped valleys are created by mountain glaciers, called fjord when filled with ocean water, creating an inlet.
Striations
Glacial striations or glacial grooves are scratches or gouges cut into bedrock by process of glacial abrasion. Glacial striations usually occur as multiple straight, parallel grooves representing the movement of the sediment-loaded base of the glacier.
Given a glacial striation at Mt. RainierCirques
A cirque is an amphitheatre-like valley head, formed at the head of a valley glacier by erosion.
Given two cirques.Glacial Horns
A glacial horn, is a mountaintop that has been modified by the action of ice during glaciation and frost weathering
. Given a classic glacial hornArêtes
An arête is a thin, almost knife-like, ridge of rock which is typically formed when two glaciers erode parallel U-shaped valleys. The arête is a thin ridge of rock that is left separating the two valleys. Arêtes can also form when two glacial cirques erode headwards towards one another, although frequently this results in a saddle-shaped pass.
Given above a glacial arete
Trim Lines
A trim line, is a clear line on the side of a valley formed by a glacier. The line marks the most recent highest extent of the glacier.
Given a trim lineHanging Valley
A hanging valley is a tributary valley with the floor at a higher relief than the main channel into which it flows. They are most commonly associated with U-shaped valleys when a tributary glacier flows into a glacier of larger volume.
Given Bridal Veil Falls in Yosemite National Park flowing from a hanging valley.Depositional Landforms
When the glaciers retreated leaving behind their freight of crushed rock and sand, they created characteristic depositional landforms. Examples include glacial moraines and eskers. Drumlins and ribbed moraines are also landforms left behind by retreating glaciers.
Glacial Moraines
A moraine is any glacially formed accumulation of unconsolidated glacial debris which can occur in currently glaciated and formerly glaciated regions, such as those areas acted upon by a past glacial maximum. This debris may have been plucked off a valley floor as a glacier advanced or it may have fallen off the valley walls as a result of frost wedging or landslide. Moraines may be composed of debris ranging in size from silt-sized glacial flour to large boulders. The debris is typically sub-angular to rounded in shape. Moraines may be on the glacier’s surface or deposited as piles or sheets of debris where the glacier has melted. Moraines may also occur when glacier- or iceberg-transported rocks fall into a body of water as the ice melts.
Given a picture of a lateral moraine.Eskers
An esker is a long winding ridge of stratified sand and gravel. Eskers are frequently several kilometres long and, because of their peculiar uniform shape, are somewhat like railroad embankments.
Given a picture of an esker.Drumlins
A drumlin is an elongated whale-shaped hill formed by glacial ice acting on underlying unconsolidated till or ground moraine.
Given a picture of esker, drumlin and moraines.
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