Deformation in the Revenue granite pluton, Mount Isa Inlier, Australia

Abstract

The Revenue granite pluton in the Mary Kathleen Zone of the Mount Isa Inlier, Queensland, has a complex internal structure due to the interference of two Early-Proterozoic phases of ductile deformation. The granite intruded into calcsilicates dated at 1780-1760Ma. A D1 shape fabric, which is present throughout the pluton, is due to intense deformation in a low angle high strain zone, probably associated with a regional phase of crustal extension. A D2-event of intense E-W shortening around 1550 Ma caused folding of the early shape fabric in the granite, and tight folding of bedding in the country rock. The present dome-shape of the pluton is mainly an effect of non-cylindrical D2 folding.