Refolding and strain in the Neoproterozoic - Early Palaeozoic Anakie Metamorphic Group, central Queensland

In central Queensland the Anakie Inlier exposes basement to Palaeozoic-Meso zoic sedimentary basins. The Anakie Metamorphic Group is a succession of ps ammitic-pelitic metasedimentary and mafic meta-igneous rocks that have been affected by greenschist to amphibolite facies low-pressure metamorphism. T he unit was deformed in the Middle Cambrian but its depositional age is unc ertain. The unit is affected by three main deformations (D-1-D-3). D-1 form ed a widely developed strong foliation (S-1) that is everywhere parallel to relict bedding where preserved. Complicated map patterns in the Rolfe Cree k and Carney Creek areas formed by interference between map-scale F-1 folds and younger structures. No mesoscopic folds associated with D-1 were ident ified. D-2 was more intense with S-2 forming a strong crenulation cleavage, with widespread microlithon development, and intense folding of S-0/S-1. S -2 cleavage/foliation is fiat lying and forms a well developed intersection lineation with S-0/S-1 (L-2) showing variable orientations within S-2. The D-2 stretching direction trends east-northeast and is indicated by mineral elongations and pressure fringes on magnetite. Strain associated with D-2 has been estimated from pressure fringes and has values of X/Y in the range 1.3 to 4.6. The variation in orientation of L-2 within domains is too scat tered to completely reflect stretching and accompanying rotation towards th e X direction and therefore likely to have formed from imposition of S-2 on a curved foliation plane (Si). D-2 is probably related to a gently dipping upper mid-crustal shear zone with west-over-east thrusting and a major com ponent of coaxial deformation. Dome and basin patterns evident in the map p atterns of the inlier formed from interference between Dg and preceding def ormations.