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Figure 5.
Examples of strain analysis using StraboTools. Red figures are edge fabric ellipses (EFEs) determined with the app, and blue figures are the imposed deformation. (A) Artificial pattern from Waldron et al. (2007), deformed along an undefined axis with strain ratio R = 1.3; the edge fabric tool gives E = 1.21 with an elongation azimuth of 133°. Correcting using Equation 1 with k = 1.3 gives , very close to imposed strain. (B) Cross-polarized thin section view of an isotropic aplite dike deformed by 20% shortening in the vertical direction and 25% stretching in the horizontal (R = 1.56), with EFE (, which corrects with Equation 1–1.56). (C) Ellipses with random axial ratios and orientations that were stretched 10% along an azimuth of 065. Agreement between the imposed strain (blue) and computed EFE (red) strain is excellent. (D) Rf /φ plot of data from C, with the imposed deformation and EFE solutions indicated by stars. It is hard to see how one could infer the imposed deformation (blue star) from the scatter of points, but the EFE solution matches it well. (E) Thin section view of deformed quartzite from Ramsay and Huber (1983, p. 118). (F) Their Fry plot derived from it, with EFE. The EFE agrees well with the elliptical void.
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