Tectono‐metamorphic evolution of the Mary Kathleen fold belt, northwest Queensland: A reflection of mantle plume processes?

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

“…Differences in the tectonothermal history of the Eastern Fold Belt compared with the Western Fold Belt have been suggested by many workers (Holmes 1992;New 1993;Lally 1997;Adshead-Bell 1998;Mares 1998;Rubenach & Barker 1998;Rubenach & Lewthwaite 2002). Until recently, most workers correlated the metamorphic peak with D 2 , which they argued occurred ca 1550 -1530 Ma (Green 1975;Page 1983;Page & Bell 1986;Connors & Page 1995;Pollard & Perkins 1997;Oliver et al 1991Oliver et al , 1999Perkins et al 1999;Reinhardt 1992a, b;Rubenach 1992;Mark et al 1998;Rubenach & Barker 1998;Foster & Rubenach 2001). For example, Foster and Rubenach (2000) proposed that the metamorphic peak occurred during the second major metamorphic episode at ca 1550 -1530 Ma, based on zircon ages in the Mt Isa area (Page & Bell 1986;Connors & Page 1995) and U -Pb SHRIMP ages of 1547 -1545 Ma for igneous zircons in foliated early granite phases in the Eastern Fold Belt, interpreted to be pre-to synregional D 2 (Blake et al 1984;Williams & Phillips 1992;de Jong 1995).…”

“…A variety of processes have been proposed to explain the high geothermal gradients necessary for this style of metamorphism. Mechanisms suggested include: compression of previously extended continental crust (Etheridge et al 1987;Oliver et al 1991); mantle delamination (Loosveld & Etheridge 1990); heat advection via intrusions due to high mantle heat flow (Vernon et al 1990;Rubenach 1992;Sandiford et al 1995;Rubenach & Barker 1998); radiogenic heating due to enrichment of heat-forming elements in the upper crust (Mildren & Sandiford 1995;Sandiford et al 1998;McLaren et al 1999); and the burial of heat-producing stratigraphic sequences (Hand & Rubatto 2002).…”

Evidence for Early Mesoproterozoic Arc Magmatism in the Musgrave Block, Central Australia: Implications for Proterozoic Crustal Growth and Tectonic Reconstructions of Australia

“…Crustal growth models of Late Archean to early Mesoproterozoic Australia (e.g., Rutland 1973;Gee 1979;Etheridge et al 1987;Wyborn et al 1988;Oliver et al 1991) have been dominated by the assumption that the Australian lithosphere was a single stabilized mass by the Late Archean. In these models, crustal formation and growth proceeded by processes such as vertical accretion involving underplating and extensional tectonism driven by mantle plumes and delamination.…”

Sequential development of a mid-crustal fold-thrust complex: evidence from the Mitakoodi Culminationin the eastern Mt Isa Inlier, Australia

“…These packages were subsequently intruded by syn-extensional plutons during the ca 1740 -1730 Ma Wonga Event Oliver et al 1991;Pearson et al 1992). This period of extension resulted in the development of gently dipping mylonitic shear zones, brittle imbricate high-angle normal faults, and widespread metasomatism in the Mary Kathleen Fold Belt (Passchier & Williams 1989;Holcombe et al 1991;Oliver et al 1991 Mid-crustal fold-thrust complex, Mt Isa Inlier 71…”