A Statistical Approach to Defining Proterozoic Crustal Provinces and Testing Continental Reconstructions of Australia and Laurentia - SWEAT or AUSWUS?

A new statistical method is proposed to compare crustal terranes and to cluster terranes into crustal provinces, regions and realms. Geochronological data on mafic igneous rocks, felsic igneous rocks, deformation history and Nd model age were collected from the recent literature for over 100 terranes. selected Laurentian terranes cluster into 9 provinces including a previously well recognized very distinctive SW USA province, region and realm. The 38 selected Australian terranes cluster into six provinces including a distinctive Gawler Province. A combined dendrogram of the 100 terranes from Laurentia, Australia and Antarctica results in 8 superprovinces and 11 provinces. Five of the superprovinces contain both Laurentian and Australian terranes. clusion of the Nevada-Californian Mojave and the San Gabriel terranes in an otherwise Australian superprovince that includes Broken Hill and Mt Isa terranes, strongly supports the AUSWUS Laurentia-Australia reconstruction rather than the SWEAT reconstruction. Low statistical similarities between western Laurentia and eastern Antarctica fail to support the SWEAT hypothesis whilst high similarities between Canadian and north Australian terranes provides weak support for AUSWUS.