Tectonic implications of Delamerian magmatism in South Australia and western Victoria

A comparison of the early Palaeozoic igneous history of the Glenelg Metamorphic Complex in western Victoria with that of the Delamerian rocks in southern South Australia supports the suggestion that they are part of a single province. In both areas, Early Ordovician, syn-tectonic, I-type diorite-granodiorite-granite magmas intrude Cambrian metasediments. With these syn-Delamerian intrusives, a younger Ordovician series of high-level, silicic, A-type granites and acid volcanics occur across SE South Australia and into western Victoria. Cambro-Ordovician magmatism in the "Delamerian province' records a tectonic history of extension, collision and then further extension. In a reconstructed Gondwanaland, the Delamerian granites of South Australia and western Victoria form part of an extensive belt which extends through western Tasmania and the eastern part of the Wilson terrane in Victoria Land. -from Authors