Crustal architecture during the early Mesoproterozoic Hiltaba-related mineralisation event: are the Gawler Range Volcanics a foreland basin fill?

Abstract

The tectonic setting of Hiltaba Suite
\n(1595–1575 Ma) magmatism within
\nthe Gawler Craton has long been
\nregarded as anorogenic, accompanied
\nby mild extension (Flint et al. 1993;
\nCreaser 1995). This evaluation was
\nlargely based on the apparently limited
\ndeformation recorded within the Hiltaba
\nSuite and Gawler Range Volcanics,
\ntheir enriched geochemical signature
\nand the high-temperature nature of
\nmagmatism. However, there is now
\ngrowing evidence that contractional
\nfault reactivation, metamorphism and
\nlocally pervasive deformation were
\nassociated with the emplacement of the
\nHiltaba Suite and the associated iron
\noxide – copper–gold (IOCG) ± uranium
\nand gold mineral systems, suggesting
\nthe existence of a compressional regime
\nin the early Mesoproterozoic Gawler
\nCraton. In this contribution, we briefly
\nsummarise evidence for crustal-scale
\nearly Mesoproterozoic deformation
\nin the Gawler Craton and suggest it
\nforms part of a broader system that
\nincorporates the Olarian Orogeny of
\nthe Curnamona Province. In the light
\nof the new data on the spatial nature
\nof early Mesoproterozoic deformation
\nand metamorphism across southern
\nAustralian Proterozoic terranes (Fig. 1),
\nwe suggest that the Gawler Range and
\nBenagerie volcanics are an unusual
\nvolcanic-fill within a foreland basin
\nthat formed within a broadly NW–SEdirected
\ncompressional regime.