Emplazamiento y deformación de diques con morfología zig-zag en rocas bandeadas y foliadas

Abstract

A rather common feature of dykes intruded in banded and/or foliated rocks is their non-planar shape. This study describes the characteristics of zig-zagging magmatic dykes that occur in the Rainy Lake area of the Canadian Archean shield. The dykes are formed by planar or curved segments of different orientations, their dilation being normal to the dyke envelope. The zig-zag pattern can be due to lithological heterogeneity and/or mechanical anisotropy of the host rock. When affected by ductile post-emplacement deformation, the zig-zagging dykes may develop into folds. Caution should be taken when using these structures as strain markers, specially in intensely deformed domains where distinction between intrusive zig-zags and folds is not straightforward