Characterising magmatic suites in the western Gawler Craton: geochemical and geochronological constraints

Abstract

The western Gawler Craton is host to two uncharacterized Paleoproterozoic magmatic suites that had previously been mapped with no geochronological or geochemical constraints. There needed to be a better understanding of the magmatic suites in order to constrain the magmatic and tectonic evolution of the understudied area. This study provides insight to the known extent of the two magmatic suites using field relationships in conjunction with petrography, geochemistry and geochronological constraints, which has implications for the geological setting and tectonic evolution during the Paleoproterozoic. U-Pb dating of an unnamed granite suite yielded ages of 1694.5±6 Ma and is classified geochemically as weakly peraluminous and high K-calc-alkalic. Age and geochemistry closely resembles that of the Tunkillia Suite granitoids and is proposed as an equivalent. Further isotopic constraints implicate a syn- late tectonic setting during the cessation of the Kimban Orogeny. U-Pb dating of a gabbroic suite revealed an age of 1712.4±6 Ma which is comparable in age and isotopic nature to mafic members of the newly proposed Peter Pan SuperSuite.