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Refolding and strain in the neoproterozoic - early palaeozoic anakie metamorphic group, central queensland

Journal Article


Abstract


  • In central Queensland the Anakie Inlier exposes basement to Palaeozoic-Mesozoic sedimentary basins. The Anakie Metamorphic Group is a succession of psammitic-pelitic metasedimentary and mafic meta-igneous rocks that have been affected by greenschist to amphibolite facies low-pressure metamorphism. The unit was deformed in the Middle Cambrian but its depositional age is uncertain. The unit is affected by three main deformations (D1-D3). Di formed a widely developed strong foliation (SO that is everywhere parallel to relict bedding where preserved. Complicated map patterns in the Rolfe Creek and Carney Creek areas formed by interference between map-scale F1 folds and younger structures. No mesoscopic folds associated with D1 were identified. D2 was more intense with S2 forming a strong crenulation cleavage, with widespread microlifhon development, and intense folding of So/Si. S2 cleavage/foliation is flat lying and forms a well developed intersection lineation with So/Si (L2) showing variable orientations within S2. The D2 stretching direction trends east-northeast and is indicated by mineral elongations and pressure fringes on magnetite. Strain associated with D2 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 L2 within domains is too scattered to completely reflect stretching and accompanying rotation towards the X direction and therefore likely to have formed from imposition of S2 on a curved foliation plane (S1). D2 is probably related to a gently dipping upper mid-crustal shear zone with westover- east thrusting and a major component of coaxial deformation. Dome and basin patterns evident in the map patterns of the inlier formed from interference between D3 and preceding deformations. �� 1998 Taylor & Francis Group, LLC.

Publication Date


  • 1998

Citation


  • Green, T. J., Fergusson, C. L., & Withnall, I. W. (1998). Refolding and strain in the neoproterozoic - early palaeozoic anakie metamorphic group, central queensland. Australian Journal of Earth Sciences, 45(6), 915-924. doi:10.1080/08120099808728445

Scopus Eid


  • 2-s2.0-0032416651

Start Page


  • 915

End Page


  • 924

Volume


  • 45

Issue


  • 6

Place Of Publication


Abstract


  • In central Queensland the Anakie Inlier exposes basement to Palaeozoic-Mesozoic sedimentary basins. The Anakie Metamorphic Group is a succession of psammitic-pelitic metasedimentary and mafic meta-igneous rocks that have been affected by greenschist to amphibolite facies low-pressure metamorphism. The unit was deformed in the Middle Cambrian but its depositional age is uncertain. The unit is affected by three main deformations (D1-D3). Di formed a widely developed strong foliation (SO that is everywhere parallel to relict bedding where preserved. Complicated map patterns in the Rolfe Creek and Carney Creek areas formed by interference between map-scale F1 folds and younger structures. No mesoscopic folds associated with D1 were identified. D2 was more intense with S2 forming a strong crenulation cleavage, with widespread microlifhon development, and intense folding of So/Si. S2 cleavage/foliation is flat lying and forms a well developed intersection lineation with So/Si (L2) showing variable orientations within S2. The D2 stretching direction trends east-northeast and is indicated by mineral elongations and pressure fringes on magnetite. Strain associated with D2 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 L2 within domains is too scattered to completely reflect stretching and accompanying rotation towards the X direction and therefore likely to have formed from imposition of S2 on a curved foliation plane (S1). D2 is probably related to a gently dipping upper mid-crustal shear zone with westover- east thrusting and a major component of coaxial deformation. Dome and basin patterns evident in the map patterns of the inlier formed from interference between D3 and preceding deformations. �� 1998 Taylor & Francis Group, LLC.

Publication Date


  • 1998

Citation


  • Green, T. J., Fergusson, C. L., & Withnall, I. W. (1998). Refolding and strain in the neoproterozoic - early palaeozoic anakie metamorphic group, central queensland. Australian Journal of Earth Sciences, 45(6), 915-924. doi:10.1080/08120099808728445

Scopus Eid


  • 2-s2.0-0032416651

Start Page


  • 915

End Page


  • 924

Volume


  • 45

Issue


  • 6

Place Of Publication