Strain analysis methodologies - Breddin method

Consider an array of fossils with bilateral symmetry

Pick a fossil and measure the orientation (a') of its base relative to a reference direction (e.g. N).

Measure the angular shear (Y) and shear strain (g) implied by the deformed axis of bilateral symmetry.

Plot a graph of g against a'.

Compare (via an overlay or replotting) the plot with a standard Breddin Graph, which has an origin at zero a' (the orientation of the X axis of the strain ellipse) and is contoured in terms of strain ratio (Rf).

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Last update: 29th January 2002
Copyright © Dr G. Lloyd, School of Earth Sciences, Leeds University, 2002