Genesis of the Archean–Paleoproterozoic Tabletop Domain, Rudall Province, and its endemic relationship to the West Australian Craton

Abstract

ABSTRACTThe Tabletop Domain of the Rudall Province has been long thought an exotic entity to the West Australian Craton. Recent re-evaluation of this interpretation suggests otherwise, but is founded on limited data. This study presents the first comprehensive, integrated U–Pb geochronology and Hf-isotope analysis of igneous and metasedimentary rocks from the Tabletop Domain of the eastern Rudall Province. Field observations, geochronology and isotope results confirm an endemic relationship between the Tabletop Domain and the West Australian Craton (WAC), and show that the Tabletop Domain underwent a similar Archean–Paleoproterozoic history to the western Rudall Province. The central Tabletop Domain comprises Archean–Paleoproterozoic gneissic rocks with three main age components. Paleo–Neoarchean (ca 3400–2800 Ma) detritus is observed in metasedimentary rocks and was likely sourced from the East Pilbara Craton. Protoliths to mafic gneiss and metasedimentary rocks are interpreted to have been emplaced and deposited during the early Paleoproterozoic (ca 2400–2300 Ma), and exhibit age and isotopic affinities to the Capricorn Orogen basement (Glenburgh Terrane). Mid–late Paleoproterozoic mafic and felsic magmatism (ca 1880–1750 Ma) is assigned to the Kalkan Supersuite, which is exposed in the western Rudall Province. The Kalkan Supersuite provided the main source of detritus for mid–late Paleoproterozoic metasedimentary rocks in the Tabletop Domain. Similarities in the age and Hf-isotope compositions of detrital zircon from these metasedimentary rocks and Capricorn Orogeny basin sediments suggests that a regionally extensive, linked basin system may have spanned the northern WAC at this time. The Tabletop Domain records evidence for two metamorphic events. Mid–late Paleoproterozoic deformation (ca 1770–1750 Ma) was high-grade, regional and involved the development of gneissic fabrics. In contrast, early Mesoproterozoic (ca 1580 Ma) high-grade deformation was localised and associated with more widespread, late-stage, greenschist facies alteration. These new findings highlight that the Tabletop Domain experienced a much higher grade of deformation than previously assumed, with a Paleoproterozoic metamorphic history similar to that of the western Rudall Province.