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Tectonic and metamorphic correlation in ancient (Proterozoic) orogenic terrains has always been problematic. This is because of the lack of a suitable reference frame to correlate deformation and metamorphic events from one orogenic terrain to another. Measurement of porphyroblast inclusion trails as Foliation Intersection/Inflection Axes (FIA) allows the chronological and kinematic linking of deformation as well as metamorphism. FIA measurements in the Mesoproterozoic Mount Isa and Georgetown inliers of the North Australian Craton have revealed two separate orogenic events (O1 and O2), which not only correlate better within the orogen but also between the two terrains. Microstructural corelations have also been made with the Mesoproterozoic rocks of the SW USA. Hence, porphyroblast inclusion trails as FIA provide a new reference frame to help correlate orogenic terrains. [ABSTRACT FROM AUTHOR]

Granitic plutons of the Wangetti and Mt Formartine Supersuites intrude the Hodgkinson Formation of the Macalister Range district of the eastern Hodgkinson Province, north Queensland, Australia. Field and microstructural analyses of country-rock fabrics and those of the granites show four deformational events (D1–D4) for the district, in common with other sectors of the Hodgkinson Province. Structural relationships show that plutons of the two supersuites were emplaced at different times. The Wangetti Granite lacks fabric development, but the deflection of country-rock cleavage trends around it and the microscale crenulation of S2 on the rims of D4 porphyroblasts within its aureole indicate syn-D4 emplacement, consistent with the Early Permian crystallisation age attributed to this pluton from isotopic evidence. Plutons of the Mt Formartine Supersuite show the effects of multiple (D2–D4) deformation. An emplacement age of 357 ± 6 Ma (latest Devonian) was obtained for this granite by SHRIMP U–Pb analyses of zircon. This identifies an early episode of plutonism for the Hodgkinson Province, most granites from which are of Permian age. The new date constrains the age of D2 for the Macalister Range district and the age of the protolith of the Hodgkinson Formation as pre-Carboniferous. It matches the age previously determined for one of several small, related granitic stocks in the southeastern Camel Creek Subprovince of the Broken River Province. Structural relationships for granites of this age suggest that their emplacement was broadly associated with the first episode of regional-scale orogenesis and the development of penetrative fabrics in the Hodgkinson – Broken River Fold Belt. [ABSTRACT FROM AUTHOR]