A Cambrian U-Pb age for the Mewstone Granite, SW Tasmania

Eleven zircon grains extracted from a sample of the Mewstone Granite yielded a best estimate age of 
495.6 ±
5.2 Ma (Cambrian: Furongian), based on ²³⁸U/²⁰⁶Pb (LA-ICPMS) with correction for common lead. The 
age is within error of that of the similar South West Cape Granite. Both bodies are coeval with 
several other western Tasmanian sub-volcanic granites that were emplaced during the waning phase of 
Mt Read Volcanics magmatism. They differ from them in their more peraluminous “S-type” composition 
and may represent a more distal phase of that magmatism, in which granitic magmas assimilated 
sedimentary material as they were emplaced into the
adjacent Proterozoic basement.