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Basement structure and its influence on the pattern and geometry of continental rifting and breakup along Australia's southern rift margin

Created 17/10/2025

Updated 17/10/2025

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Palaeogeographic reconstructions of the Australian and Antarctic margins based on matching basement structures are commonly difficult to reconcile with those derived from ocean floor magnetic anomalies and plate vectors. Following identification of a previously unmapped crustal-scale structure in the southern part of the Delamerian Orogen (Coorong Shear Zone), a revised plate reconstruction for these margins is proposed. This reconstruction positions the Coorong Shear Zone opposite the Mertz Shear Zone and indicates that structural inheritance had a profound influence on the location and geometry of continental breakup, and ocean fracture development. Previously, the Mertz Shear Zone has been correlated with the Proterozoic Kalinjala Mylonite Zone in the Gawler craton but this means that Australia is positioned 300-400 km too far east relative to Antarctica prior to breakup. Differences in the orientation of late Jurassic-Cretaceous basin-bounding normal faults in the Bight and Otway basins further suggest that extensional strain during basin formation was partitioned across the Coorong Shear Zone following an earlier episode of strike-slip faulting on a northwest-striking continental transform fault (Trans-Antarctic Shear).

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Title Basement structure and its influence on the pattern and geometry of continental rifting and breakup along Australia's southern rift margin
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/b4fe4d92-54e5-4b94-aa7a-9c08f9a07bc3
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage Australia
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Basement structure and its influence on the pattern and geometry of continental rifting and breakup along Australia's southern rift margin". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/basement-structure-and-its-influence-on-the-pattern-and-geometry-of-continental-rifting-and-bre