Glaciers

Essential Points• Glaciers are flowing streams of ice

• Glaciers have a zone of accumulation where snowfall exceeds losses (ablation)

• Accumulation can be due to high altitude (mountain glaciers) or cold climate (continental glaciers)

• Glaciers have a zone of ablation where losses exceed snowfall

• Glaciers are governed by a balance of snowfall, ice flow, and ablation

• Glaciers retreat by melting back, not by retracting

• Glaciers produce distinctive landforms and small scale features

Snowfall vs Melting & Evaporation (Ablation)

Zone of Accumulation

• Mountain

• Continental (Greenland, Antarctica

Zone of Melting or Ablation

Terminus of Glacier

• Ablation = Accumulation+ Flow

Small Glacier, Antarctica

Anatomy of a Glacier

A Typical Glacial Advance and Retreat

Mountain Glacier

Landforms

Glacial Valley, Yosemite, California

Cirque, Oregon

Cirques, Colorado

The Mother of All Cirques, Mount Everest

Glaciated Landscape, Sierra Nevada

What it May Have Looked Like

Glacier, Antarctica

Moraines, Colorado

Moraine, Washington

Glacier and Moraines, Peru

Continental Glacier

Landforms

Greenland Ice Cap

Antarctic Ice Cap

Continental Glacier, Antarctica

Glacial Deposits, Ontario

Dropstone, Ontario

Erratic, Washington

Kettles, Madison, Wisconsin

Roche Moutonnee, Wisconsin

Crescentic Gouges, Wisconsin

Chatter Marks, Wisconsin

Drumlins, Wisconsin

Buried Log, Wisconsin

Till and Outwash, Wisconsin

Sculpted Bedrock, Ontario

Antarctic Subglacial Lakes

Lake Vostok

Essential Points• Glaciers are flowing streams of ice

• Glaciers have a zone of accumulation where snowfall exceeds losses (ablation)

• Accumulation can be due to high altitude (mountain glaciers) or cold climate (continental glaciers)

• Glaciers have a zone of ablation where losses exceed snowfall

• Glaciers are governed by a balance of snowfall, ice flow, and ablation

• Glaciers retreat by melting back, not by retracting

• Glaciers produce distinctive landforms and small scale features