Chapter 17

Glacial Modification of Terrain: 

Glacial Modification of Terrain Pleistocene Glaciation How glaciers form Types of glaciers Glacial erosion Glacial landforms

North American Glaciation: 

North American Glaciation During the Pleistocene Canada covered South to KS, MS, KY Most mountainous areas Today Much more limited Great Lakes Finger Lakes Alaska and Canada Western Mountains Rockies Cascades

Slide3: 

Snow and neve Glacial margin Advancing vs Receding Glacial Development

Types of Glaciers: 

Types of Glaciers Valley Glacier Icefields Alpine Glaciers Mountain Glaciers Valley Glaciers Alpine Icefields Cirque Piedmont Glaciers Ice Sheets

Glacial Movement: 

Glacial Movement As a glacier grows in size and mass, gravity begins to propel it downslope. Its speed is governed by multiple factors including As the glacier moves downslope, it picks up rocks and debris. A glacier’s rate of movement may be determined by monitoring and charting the location of recognizable rocks and debris. In the series of diagrams below observe the large rock move downslope. The glacier is moving from right to left down a hill. The red arrow marks the same rock in each diagram specific rock. The glacier’s movement exerts a powerful erosive force. All of the material that the glacier erodes is later deposited due to melting at the mouth of the glacier. The erosion and deposition creates unique landforms. and bedrock base. size, slope, obstacles,

Athabaska Glacier: 

Athabaska Glacier Icefield Icefalls Outwash plain Valley glacier Crevasses

Glacial Erosion: 

Glacial Erosion

Erosion Landforms: 

Erosion Landforms Photos from University of Cincinnati Glacier Gallery.

Deposition: 

Deposition The two broad terms for material transported and deposited by glaciers are glacial flour (or rock flour) and glacial till.

Depositional Features: 

Depositional Features Photos from University of Cincinnati Glacier Gallery.

Slide11: 

Depositional Features

Summary: 

Summary This lecture introduced the concept of glaciers and glaciation. For a more in depth course, take ES 331 (ES 767), Ice Age Environments offered by the ESU Earth Sciences Department. There are two basic types of glaciers – ice sheets and mountain glaciers. This lecture tended to concentrate on mountain glaciers. Study the text for more information on ice sheets. Glaciers dramatically alter the landscape through both erosion and deposition. Erosion is most notable in features formed by mountain glaciers such as those in Alaska or western Canada. Deposition is most notable in features formed by ice sheets such as those in Wisconsin or New York. Glaciers also contribute greatly to fluvial processes as discussed in an earlier chapter. Glaciers often spawn sizable rivers and contribute tons of sediment for transport and deposition.

Sources: 

Sources Hambrey, Michael. Glacial Environments. UBC Press, Vancouver, 1994. Hamilton College Geology Ice at Rice University Indiana University and Purdue Fort Wayne University Department of Geosciences Klosterman, Donald. In Search of Splendor. Physical Geography: A Landscape Appreciation, 6th Edition. Tom L. McKnight. Prentice Hall, Upper Saddle River, NJ 1999. Physical Geography: A Landscape Appreciation, 6th Edition Presentation Manager 3.0. Tom L. McKnight. Prentice Hall, Upper Saddle River, NJ 1999. University of Cincinnati Glacier Image Database