Geodynamic significance of the boundary between the Thomson Orogen and the Lachlan Orogen, northwestern New South Wales and implications for Tasmanide tectonics

Early Palaeozoic continental growth in the Tasmanides of northeast Gondwana and its implications for Rodinia assembly and rifting

“…Quartzose turbidites and island arc assemblages have also been accreted to the East Gondwana margin during the Middle to Late Cambrian Delamerian Orogeny in the Delamerian Orogen of southeastern South Australia, western Victoria, Tasmania and northwestern New South Wales (Preiss, 2000;Cayley, 2011;Gibson et al, 2011;Greenfield et al, 2011;Moore et al, 2013). It is now recognised that the Thomson Orogen of Queensland and northwestern New South Wales is probably largely related to this early phase of continental growth in the Delamerian Orogeny (Withnall et al, 1996;Fergusson and Henderson, 2013;Glen et al, 2013) rather than being a continuation of the Lachlan Orogen as argued previously (Murray and Kirkegaard, 1978;Powell, 1984a;Murray, 1986).…”

“…It is therefore equivalent to units of the eastern Delamerian Orogen including the Kanmantoo Group and western-most part of the Lachlan Orogen in the Stawell Zone of western Victoria, and the Koonenberry Belt of northwestern New South Wales (Preiss, 2000;Greenfield et al, 2010Greenfield et al, , 2011Cayley, 2011). Glen et al, 2013). Dots show locations of basement cores in the Thomson Orogen and eastern Warburton Basin in Queensland (from Brown et al, 2012).…”

“…Dark-shaded regions, including in the Timbury Hills Basin and a region in the southwestern Thomson Orogen, show areas with abundant basement cores. Radiometric ages from basement cores (filled in circles, in Ma) and surface exposures (crosses) shown for the Thomson Orogen in Queensland (Draper, 2006) and northwestern New South Wales (Greenfield et al, 2010(Greenfield et al, , 2011Glen et al, 2013). For the Thomson Orogen in northwestern New South Wales extent of inferred subsurface granite (red) and main area of inferred subsurface Warraweena Volcanics (green, WV) are shown (after Glen et al, 2013).…”

“…Map showing gravity data for Australia with outlines (heavy black lines) of Precambrian cratons and prominent geophysical lineaments in and at the boundaries of the Tasmanides of eastern Australia (red lines). Gravity image adapted from the onshore national gravity anomaly dataset (Bacchin, 2009 Glen et al (2013) with ages of the Hungerford Granite and Granite Springs Granite from Bultitude and Cross (2013). Thomson basement in Queensland (west and southwest of the Anakie Province) -U-Pb zircon ages (Draper, 2006) and detrital zircon ages from Brown et al (2014), Anakie Province -fossil ages from the Fork Lagoons beds (Withnall et al, 1995), K/Ar ages from the Anakie Metamorphic Group (Withnall et al, 1996), U-Pb detrital zircon ages (Fergusson et al, 2001(Fergusson et al, , 2007a, 39 Ar/…”

“…However, new information has become available in the last decade enabling a wider appreciation of its tectonic significance for the development of the East Gondwana active margin Fergusson and Henderson, 2013;Glen et al, 2013). The Thomson Orogen, although largely concealed by younger sedimentary basins, has a westward connection to sedimentary basins in central Australia via the Warburton Basin ( Fig.…”