The Tectonothermal Evolution of the Gascoyne Province and its Role in Proterozoic Australia

Abstract

SHRIMP U-Pb phosphate geochronology was used to date low- to high-grade metamorphism and leucocratic magmatism associated with Proterozoic intraplate reworking in the Gascoyne Province of Western Australia. The results show that regional metamorphism is probably related to emplacement of magmas rather than to the presence of a thermal lid as widely proposed. Late reactivation of the province, which established the present crustal architecture, was successfully dated using 40Ar/39Ar mica geochronology.