Folds

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Folds
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Folds

• structure produced when an originally planar
  surface is bent or curved
• Rock breaks discontinuous deformation
• brittle
• Rocks flow or fold continuous deformation
• ductile

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Fold Terminology

• Axial Plane
• Axial Surface
• Axial Trace

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Wavelength and Amplitude
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Structural Facing Direction

• Syncline vs Anticline

Mt Kidd, Alberta (courtesy of Borealisoutdoor.com)
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Fold orientation
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Fold Style
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Flexural Slip folding

• Forms in strong/stiff layers with weak contacts

From Geoff Tanner
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• Outer arc joints and/or keystones
• Inner arc thrust faults, folds and/or cleavage

http//ic.ucsc.edu/casey/eart150/Lectures/Folds/f
oldingmechanisms.htm
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Examples Disharmonic folds

• Wavelength differ
• Do thicker layers have longer wavelengths?

Courtesy of M. Miller