Evolution of the Isan Orogeny at the southeastern margin of the Mt Isa Inlier

Australia and Nuna

“…Palaeomagnetic data suggest that Australia and Laurentia were in close proximity at c. 1595 Ma Hamilton & Buchan 2010), indicating that the ocean was relatively small. Final closure of this ocean and the re-amalgamation of Australia and Laurentia must have post-dated arc magmatism in the Etheridge Province and is therefore likely to be recorded by the waning stages of the Isan Orogeny Giles et al 2006;Blenkinsop et al 2008;Fig. 15c).…”

Mesoproterozoic plume‐modified orogenesis in eastern Precambrian Australia

“…At the onset of the Mesoproterozoic large tracts of central and eastern Australia underwent a period of orogenesis (circa 1620 and 1580 Ma) (Figure 10). The orogenic history is preserved in the Arunta Inlier (Chewings Orogeny), Curnamona Province (Olarian Orogeny), Gawler Craton (Kararan Orogeny), Mount Isa Inlier (Isan Orogeny) and Georgetown Inlier (Jana Orogeny) [ Betts et al , 2006; Blenkinsop et al , 2008; Cihan et al , 2006; Cihan and Parsons , 2005; Collins et al , 1995; Daly et al , 1998; Forbes et al , 2004, 2007; Gibson et al , 2008; Giles et al , 2006b; Hand et al , 2007; MacCready , 2006a; O'Dea et al , 1997b, 2006; Potma and Betts , 2006; Rubatto et al , 2001; Vry et al , 1996] (Figures 1 and 10). The circa 1610–1560 Ma Chewings Orogeny [ Collins and Shaw , 1995] is characterized by early thin‐skinned deformation and nappe emplacement during north directed thrusting [ Teyssier et al , 1988], followed by the development of upright, shallowly plunging folds with ∼east‐west trending axial traces [ Collins and Shaw , 1995].…”

“…Time‐space diagram with the age and style of orogenesis throughout eastern Australian Proterozoic geological provinces [ Bell , 1983; Betts et al , 2000; Binns , 1964; Blake , 1987; Blewett and Black , 1998; Blewett et al , 1998; Boger and Hansen , 2004; Cihan et al , 2006; Cihan and Parsons , 2005; Clark et al , 2006a, 2006b; 1986, 1987; Collins and Shaw , 1995; Collins et al , 1995; Connors and Page , 1995; Daly et al , 1998; Davis et al , 2001; De Jong and Williams , 1995; Etheridge and Cooper , 1981; Forbes and Betts , 2004; Forbes et al , 2004, 2005, 2007; Ganne et al , 2005; Gibson and Nutman , 2004; Gibson et al , 2004; Giles et al , 2006a, 2006b; Giles and Nutman , 2002, 2003; Hills , 2004; Hobbs et al , 1984; Laing et al , 1978; Lewthwaite , 2001; Lister et al , 1999; Loosveld , 1992; MacCready , 2006a, 2006b; MacCready et al , 1998, 2006; Marjoribanks et al , 1980; McLean and Betts , 2003; O'Dea et al , 2006; O'Dea and Lister , 1995; O'Dea et al , 1997a; Oliver et al , 1998; Foster and Rubenach , 2006; Page et al , 2005a; Page and Laing , 1992; Potma and Betts , 2006; Raetz et al , 2002; Reinhardt , 1992; Reinhardt and Rubenach , 1989; Rubenach , 1992; Rubena...…”

“…In the Mount Isa Inlier, the Isan Orogeny [ Bell , 1983; Betts et al , 2006; Blake and Stewart , 1992; O'Dea et al , 1997b; Page and Bell , 1986] has been interpreted to span more than 100 Ma (Figure 10) but most likely represents multiple orogenic events [ Betts et al , 2000, 2006; Giles et al , 2006a; O'Dea et al , 2006; Sayab , 2008] with several discrete episodes of metamorphism [ Connors and Page , 1995; Foster and Rubenach , 2006; Giles et al , 2006b; Giles and Nutman , 2002, 2003; Page and Sun , 1998; Rubenach , 1992; Rubenach and Barker , 1998; Rubenach and Lewthwaite , 2002]. In the relatively low strain regions of the Western Fold Belt the early stages of the Isan Orogeny involved inversion of the rift‐sag basins during both north‐south and east‐west shortening resulting in normal fault reactivation, development of localized foliations and development of north to northeast trending upright folds (Figure 7) [ Betts et al , 2004; Lister et al , 1999; O'Dea and Lister , 1995; O'Dea et al , 1997a].…”

“…The latest Paleoproterozoic to early Mesoproterozoic (1620–1500 Ma) evolution of eastern and central Australia (Figure 1) is characterized by continental‐scale tectonic events that affected almost a third of the continent and lasted approximately 100 Ma. Tectonism associated with these events is variably expressed but includes the development of large felsic igneous provinces [ Betts et al , 2007; Creaser , 1995, 1996; Creaser and White , 1991; Fanning et al , 2007; Mark , 2001; K. Stewart and J. Foden, Primary Industry and Resources South Australia, University of Adelaide, The Mesoproterozoic granites of South Australia, unpublished report, 2001], widespread high‐temperature metamorphism [ Daly et al , 1998; Forbes et al , 2008; Giles et al , 2006b; Hand et al , 2007; Loosveld , 1989; McLaren et al , 2005; Rubatto et al , 2001; Rubenach , 1992; Rubenach and Barker , 1998; Rubenach et al , 2008; Stüwe and Ehlers , 1997; Teasdale , 1997; Vry et al , 1996] and polycyclic orogenesis over large areas of the continent [ Betts et al , 2006; Blenkinsop et al , 2008; Clarke et al , 1986; Collins and Shaw , 1995; Daly et al , 1998; Forbes and Betts , 2004; Forbes et al , 2004; Giles et al , 2006a; Hand et al , 2007; O'Dea et al , 1997b; Withnall et al , 1988]. The extent and duration of this episode of tectonism places it as the single largest Mesoproterozoic event to impact the evolution of the Australian continent and is one of the largest thermal recorded in the entire geological evolution of the Australian continent [ Betts et al , 2002].…”