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| Titel: |
Refolding and strain in the Neoproterozoic - Early Palaeozoic Anakie Metamorphic Group, Central Queensland |
| Auteur: |
Green, T. J. Fergusson, C. L. Withnall, I. W. |
| Verschenen in: |
Australian journal of earth sciences |
| Paginering: | Jaargang 45 (1998) nr. 6 pagina's 915-924 |
| Jaar: |
1998-12 |
| Inhoud: |
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). D1 formed a widely developed strong foliation (S1) 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 microlithon development, and intense folding of S0/S1. S2 cleavage/foliation is flat lying and forms a well developed intersection lineation with S0/S1 (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 west-over-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. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 14 van 16 gevonden artikelen
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