Correlation between the anisotropy of the magnetic susceptibility, strain and X-ray texture goniometry in phyllites from Crete, Greece

Abstract

A comparison of petrofabric and strain in phyllitic rocks from Crete, Greece has been undertaken using Anisotropy of Magnetic Susceptibility (AMS) at room and low temperature, the Projected Dimension Strain method (PDS), and X-ray Texture Goniometry (XTG) of phyllosilicates. The magnetic (at room and low temperature) and strain fabrics show similar orientations, with the minimum axes of the AMS ellipsoid coincident with the flattening direction of a pronounced solution mass-transfer deformation (SMT). The kmax axes of the AMS and the maximum stretching axis of the deformation overlap in the NNE–SSW direction, parallel to the axes of macroscopic folds. The quantitative relationship between the absolute values of strain and AMS is unclear. Nevertheless, a degree of correlation is found between the Woodcock diagram values of AMS and strain. Sx values discriminate better the clustered samples of kmax whereas the girdled samples of kmax are better differentiated with the Sz values. The stacking of the octahedral layers in micas correlates with Sx in the clustered kmax axes fabrics. The lack of a clear quantitative relationship is probably related to the generation of new phyllosilicates during folding and SMT deformation.