Description:
Cusp-corrugations with a highly ordered alignment are nicely exhibited in the Flamierge area. These structures due to boudi¬ nage are located on the bedding plane, at the top of a pelitic layer overlaid by a massive sandstone layer. Data measurements do not show significant variations between the different planes of cleavage and interboudin vein. In the thicker interboudin veins, crystal fibres are observed transverse rather than perpendicular to the walls of the veins. Such fibres, indicating dilatant shear and pro¬ gressive growth during boudinage, can be slightly curved and sometimes exhibit sigmoid shapes.