Early Palaeozoic subduction in the southeastern Lachlan Fold Belt,Batemans Bay,New South Wales |
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Authors: | E. I. Prendergast |
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Affiliation: | 1. Discipline of Earth Sciences , School of Environmental &2. Life Sciences, University of Newcastle , NSW, 2308, Australia lprendergast@srk.com.au |
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Abstract: | The southeastern Lachlan Fold Belt at Batemans Bay on the New South Wales south coast is an accretionary complex with a prolonged deformation history. Early features include synsedimentary folds, mélange, disaggregated bedding and faults. Fabrics within the clast-in-matrix mélange and mudstone match those found in cores from the lower slopes of modern accretionary prisms. At the toe of the accretionary prism, the contact between the craton-derived Adaminaby Group and ocean floor deposits of the Wagonga Group is conformable. As subduction continued, the early structures were overprinted by (D1) deformation that produced meridional north – south-trending, tight to isoclinal folds (F1) and associated axial-plane cleavage (S1). This west-dipping subduction occurred in the Late Ordovician/Early Silurian but probably began much earlier. A younger regional deformation (D2) resulted in north – south-trending, open to tight folds (F2), slightly oblique to F1, and an axial-surface cleavage (S2). |
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Keywords: | accretion Adaminaby Group Batemans Bay Lachlan Fold Belt mélange subduction thrust faults Wagonga Group |
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