Glacial Ogives

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Glacial Ogives

• Logan King

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• Ogives are one of the most enigmatic indicators
  of glacier flow and are of two main types wave
  ogives and band ogives (Goodsell et al.)

Ogives on Juno icefield
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Ogive Basics

• Two major types Wave and Band
• Occur down ice from icefalls
• Useful in velocity calculations and identify
  basal features

• A.K.A. Forbes or Alaskan Bands

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Wave (Swell-and-swale) Ogives

• Alternating crests, convex down ice
• Velocity is a function of wavelength and
  amplitude

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Wave (swell-and-swale) Ogives

• Ogives are formed anually, alternating crest1
  year advancement
• Icefall travel time lt 6 mo.
• James Forbes (mid 19th century) indicator of
  velocity

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Case Study 1(Wave Ogive)

• Bilchenok Glacier in Kamchatka (2006)
• Surging glacier, volcanic region

Formed below steep icefall Angular-sub
angular Long record of movement and surge
history Surge interval and phase velocities
preserved in ogives
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Band Ogive

• Alternating convex bands of dark and light
• Color can be debris based or ice density

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Case Study 2 (Band Ogive)

• Bas Glacier dArolla Switzerland (2002)
• Mt. Collon, small glacial branch
• Folding occurs in the icefall
• Stratification preserved

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Case Study 3 (Band Ogive)

• Kviàrjökull, Southeatern Iceland (2004)
• Over deepening below the icefall results in
  transverse thrusting

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Ogive Thought

• Formed annually only if lt6 mo. To travel through
  icefall (Waddington 1986)
• Two methods of formation

• Can form on surge glaciers
• Multiple working hypothesis

• Old

• New

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Conclusion

• Ogives are alternating colors or ridges on
  glaciers
• Can form on surging glaciers
• Used to determine velocities or surge intervals
• Can be used to predict crevasse formation by
  identifying crevasse scars

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Refrences

• Evans, D, Benn, D (1998). Glaciers and
  Glaciation.London Hodder.
• Evans J.A., Swift D.A., Fallick A.E. , (2004)
  Transverse Englacial Debris-rich Bands at
  Kviarjokull, Southeast Iceland Quaternary
  Science Reviews 25, 2006 1708-1718
• Yamaguchi Et al. (2002) Influence of Debris Cover
  on Ogive-like Surface Morphology of Bilchenok
  glacier in Kamchatka , BioOne, Arctic, Antarctic,
  and Alpine Research. 39(2)332-339. 2007
• Goodsell B., Hambry M.J., Glasser N.F., (2002)
  Formation of Band Ogives and Assosciated
  Structures at Bas Glacier dArolla, Valais,
  Switzerland, Journal of glaciology, vol 48, No.
  161