Isograd pattern and regional low-pressure, high-temperature metamorphism of pelitic, mafic and calc-silicate rocks along an east – west section through the Mt Isa Inlier

The Australo-Antarctic Columbia to Gondwana transition

“…The early stages of orogenisis involved thin-skinned thrusting and basin inversion associated with north-south to northwest directed crustal shortening, also associated with high temperature metamorphism, ca. 1590-1580 Ma (Foster and Rubenach, 2006). Eastwest crustal shortening at ca.…”

The noble gas systematics of late-orogenic H2O–CO2 fluids, Mt Isa, Australia

“…The Eastern Fold Belt of the Mt Isa Inlier comprises Clrich (meta-evaporitic) calc-silicates and subordinate metapelites that reached greenschist to amphibolite facies during peak metamorphism at 1595-1575 Ma (Foster and Rubenach, 2006). These rocks were intruded by the late-orogenic Williams-Naraku Batholiths at 1550-1490 Ma ( Fig.…”

Synthesis of the proterozoic evolution of the Mt Isa Inlier

“…The early orogenic history of the Isan Orogeny involved northwest thrusting of young hot Calvert and Isa Superbasin rocks of the Soldiers Cap Group, Marimo and Staveley Formations, and Tommy Creek beds over the older and colder Leichhardt Superbasin rocks during basin inversionGiles et al 2006;O'Dea et al 2006). Deformation was accompanied by low-pressure upper greenschist to amphibolite facies metamorphism at ca 1585 Ma(Page & Sun 1998;Giles & Nutman 2002Hand & Rubatto 2002), with metamorphic grade generally increasing to the southeast(Foster & Rubenach 2006), presumably towards the core of the orogen. Large recumbent folds formed in the Kuridala area(Betts et al 2000), the Marimo -Staveley Block(Loosveld 1989a;O'Dea et al 2006), and the Tommy Creek Block(Hill et al 1992;O'Dea et al 2006), and in the Soldiers Cap Group southeast of Cloncurry (Loosveld 1989a, b) (Figure 6).…”