THE ROLE OF RHEOLOGY IN THE EMPLACEMENT AND DEFORMATION OF SYNTECTONIC VEINS

Syntectonic veins and dikes are common throughout many orogenic belts. As each progressive vein records a smaller partial record of the strain history, multiple generations of such intrusions may be useful tools with which to unravel the deformation path. When conducting such strain path studies, several factors are necessarily considered. Two commonly considered factors are the orientation of the veins and the relative timing of their emplacement. However, factors that are also important include the changing rheology of the crystallizing veins and the variable nature of the host rock in which the veins intrude. We wish to draw attention to these rheological parameters for the study of emplacement and deformation processes. We present an example of syntectonic veins from the Rainy Lake District of the Superior Province. There, complex structures resulting from the interaction between magmatic and deformational processes are displayed. Moreover, there is evidence that host-rock rheology strongly influences the emplacement (and thus the initial shape and orientation) and the subsequent deformation of veins. These phenomena must be taken into account when using syntectonic intrusions to unravel deformation paths.