Rock Glaciers Travis Corthouts

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Rock GlaciersTravis Corthouts
https//www.allposters.com/-sp/The-Longest-Ro...
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What's to Come

• Quick review of rock glaciers
• Beartooth rock glacier survey
• Hypotheses
• Results

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Quick Facts/Review

• Rock glaciers look similar to ice glaciers, as
  they commonly have ridge and furrow surface
  topography and steep snouts.
• Composed of angular boulders mixed with ice and
  permafrost depending on the origin of formation.
• Thickness varies between 1550 meters and move
  continuously at rates of centimeters to meters
  per year.
• Little or no visible ice at surface

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Two Types Commonly Recognized

• Ice Cored
• Ice Cemented

Ice-Cored Will have a surface layer, up to
several meters thick, of rock fragments which
covers subsurface ice. Rock layer likely shields
the permanently frozen ice-core from
radiation. Ice-Cemented These glaciers will
have a mix of rock fragments which are cemented
by interstitial ice. Possible formation
triggered by snow melt percolating into
accumulated talus, refreezes as interstitial ice.
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Dr. Bruce Railsback www.gly.uga.edu/railsback/20
96RockGlaciers.jpeg
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Flow

• Presence of ridge and furrow surface topography
  supports continuous movement.
• Mechanisms
• Flowage of ice
• Creeping via frost action
• Deformation of internal ice is likely to be the
  most important factor in movement of rock
  glaciers.

http//en.wikipedia.org/wiki/ImageGlacierrock1.gi
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The Beartooths!!!A rock glacier story
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The Premise

• Goal Gain insight about controlling factors for
  rock glaciers of SW Montana.
• Tools Google Earth, geologic maps, topographic
  maps
• Source Caitlyn Florentine, who is doing
  graduate work on rock glaciers has provided me
  with several hypothesis she will be testing
  through a survey of rock glaciers across the U.S
  Thanks Caitlyn!

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The Glaciers
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Hypotheses
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Length to Width Ratio
Figure 1
Beartooth rock glacier with a length to width
ratio close to 1, which is support against the
Hamilton and Whalley, 1995 hypotheses.
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longest rock glacier in the Dry Valleys descends
into Beacon Valley, Antarctica
Figure 2
This Rock glacier is larger than 1 km², which
goes against the Brenning, 2005 hypothesis that
rock glaciers cant exceed 1 Km²
www.ngsprints.co.uk/images/M/516260.jpg
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Bibliography

• D. F. Ritter, R. C. Kochel, and J. R. Miller
  2002, Process Geomorphology (4th), W. C. Brown,
  Dubuque, IA, pp. 387-389
• Benn, D. I., and Evans, D. J.A., 1998. Glaciers
  and Glaciation. Arnold and Oxford University
  Press