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The Polda Basin - a seismic interpretation of a Proterozoic-Mesozoic rift in the Great Australian Bight

Created 16/10/2025

Updated 16/10/2025

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The Polda Basin is an elongate easterly trending trough underlying the continental shelf in water depths of 50-200 m on the eastern side of the Great Australian Bight. It encompasses an area of about I0 000 km2, and contains a Proterozoic-Jurassic sedimentary fill. Although it was originally an intracratonic feature, it shows evidence of several phases of tectonism, of which the most recent culminated in the separation of Australia and Antarctica in the mid-Cretaceous. Seismic interpretation indicates that the trough contains three main depocentres. The eastern Polda Basin lies almost entirely onshore, and contains 1500-2000m of Proterozoic-Jurassic sedimentary rocks. The central Polda Basin and underlying Itiledoo Basin contain a maximum of 5000m of Proterozoic-Jurassic Gontinental sedimentary rocks, including massive halite. They are bounded to the south by a set of normal faults, and to the north by a complex faulted monocline. The western Polda Basin is apparently bounded, north and south, by relatively simple sets of east-northeasterly trending normal faults, and is interpreted to contain a mainly Mesozoic sedimentary fill. The central depocentre, in particular, has been affected by northwesterly oriented wrenching. Overall, the hydrocarbon potential of the Polda Basin is rated as low. None of the three offshore wells drilled encountered significant hydrocarbons; even so, the western depocentre is as yet untested. Potential reservoirs appear to be present, and a number of potential trapping mechanisms can be identified. Such potential traps include halite-induced anticlines, Proterozoic fault-blocks, clastic aprons adjacent to boundary faults, and unconformity traps below the Permo-Carboniferous section. Unfortunately, the existence of suitable source and seal sequences is doubtful, and the basin appears to be too immature for significant hydrocarbons to have been generated. The western Polda Basin is considered to be the most prospective, as inferred by exploration drilling elsewhere in the Great Australian Bight, which shows that Mesozoic sedimentary rocks have some hydrocarbon potential.

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Field Value
Title The Polda Basin - a seismic interpretation of a Proterozoic-Mesozoic rift in the Great Australian Bight
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/f4119569-9e96-4770-ad9c-ac584f03c4d5
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        125.0,
        -37.0
      ],
      [
        137.0,
        -37.0
      ],
      [
        137.0,
        -31.0
      ],
      [
        125.0,
        -31.0
      ],
      [
        125.0,
        -37.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "The Polda Basin - a seismic interpretation of a Proterozoic-Mesozoic rift in the Great Australian Bight". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-polda-basin-a-seismic-interpretation-of-a-proterozoic-mesozoic-rift-in-the-great-australian