Magnetotelluric constraints on the tectonic setting of Grenville-aged orogenesis in central Australia

Abstract

Magnetotelluric (MT) data were collected over a 480 km long profile in central Australia, extending from the Mesoarchaean-Palaeoproterozoic Gawler Craton into the Mesoproterozoic-Neoproterozoic Musgrave Province. The two regions have contrasting geological histories and many reconstruction models of Proterozoic Australia propose that they were juxtaposed during the Mesoproterozoic. Despite the significant differences in geological background between the Gawler Craton and the Musgrave Province, the MT data did not image an electrical structure, or any change in electrical character, between them. MT models suggest that southern-central Australia is electrically separated into two parts. The first, comprising the northernmost Gawler Craton and the Musgrave Province, has a 5 km thick layer of moderate resistivity overlying highly resistive crust. The second, comprising the central-northern Gawler Craton, displays moderate resistivity to the base of the crust. The lithospheric mantle underlying both electrical regions is uniformly highly resistive. Our results suggest that the Musgrave Province and Gawler Craton are more closely related than is currently recognized. We propose that the Gawler Craton forms basement to the Musgrave Province and that the Grenvillian Musgrave Orogeny was an intracratonic reworking event that overprinted the older basement.

The Australo-Antarctic Columbia to Gondwana transition

“…The Warumpi Province is apparently continuous beneath the entire Amadeus Basin, and even into the northern Musgrave Province, with no major east-west oriented geophysical discontinuities suggestive of a suture zone (Korsch et al, 1998;Selway et al, 2011). The Warumpi Province has a younger protolith, and less-evolved isotopic signatures than the Aileron Province .…”

A duality of timescales: Short-lived ultrahigh temperature metamorphism preserving a long-lived monazite growth history in the Grenvillian Musgrave–Albany–Fraser Orogen

“…It is geographically central to the surrounding Archaean to Palaeoproterozoic NAC, WAC and SAC, and is presently overlain by and structurally juxtaposed against the Neoproterozoic to Palaeozoic Amadeus, Officer and Eromanga basins to the north, south-west, and east, respectively (Kirkland et al, 2013;Smithies et al, 2011;Wade et al, 2008). Although Neoproterozoic to Cenozoic cover largely obscures the margins of the Musgrave Inlier, the terrane is expansive, likely continuing beneath the Amadeus and Officer basins Betts, 2008, 2009a,b;Selway et al, 2011).…”

“…The MAFO is widely interpreted to have formed during the amalgamation of Proterozoic Australia, although the specific mechanism Kirkland et al (2011) and Walsh et al (2014). which largely obscure the contact relationship between the orogenic system and enclosing cratons, as well as much of the internal character of the belt Betts, 2008, 2009a,b;Selway et al, 2011;Wade et al, 2008).…”

From Surface to Mantle; An Overview of Downloadable MT Data from South Australia

“…These sites form part of a survey designed to investigate the relationship between the Gawler Craton and the Musgrave Block (Selway et al, 2011).…”