Preliminary results from AMS studies of the deformed Wyangala Granite, Cowra, New South Wales, Australia
Lennox, Paul; de Wal, Helga; Czarnota, Karol; White, Lloyd
:The Early Silurian Wyangala Granite passively intruded already deformed Ordovician greywackes and volcaniclastics and was later deformed in the late Early Devonian and Early Carboniferous. The deformed Wyangala Granite contains discontinuous, north-south oriented high strain shear zones along its eastern margin which were defined using the prevalence and angle between Sand C structures, the presence and thickness of mylonites or ultramylonites and the size ofK-felspar phenocrysts. This preliminary study of cores from high and lower strained portions of the Wyangala Granite was aimed at understanding the form of fabric development from low strained parts of the granite to more highly strained mylonitised parts of the granite. The Jelinek diagram shows a clear pattern of increasing anisotropy of the magnetic fabric with the transition from biotite granite with megacrysts and Sand C structures to that showing protomylonitisation. Further microstructural work is required to properly characterise the mineralogical and kinematic changes related to the observed AMS pattern.