Nature and Origin of Foliation and Lineation in Porphyry, Killarney, Ontario

Abstract

<p> The Killarney Igneous Complex, composed of an intrusive granite and a hypabyssal or extrusive porphyry was implaced near and at the surface in the general locality of Killarney, Ontario. The crystallization age of the intrusive portion of the complex is approximately 1740 million years. These rocks have experienced deformation by forces which in some instances produced complicated shearing motions. Mesoscopic samples show a foliation and a lineation supporting a history of deformation. The foliation is clearly the more visible fabric and is interpreted as a plane of flattening.</p> <p> Kinematic indicators, specifically asymmetric pressure shadow wings, are present within the rocks; however the patterns are too complicated to interpret by a simple sense of shear. The geometry of these kinematic indicators does suggest an active plane of foliation.</p>