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The Cretaceous of the Eromanga and Surat Basins

Created 08/01/2026

Updated 08/01/2026

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Little deformed Cretaceous sedimentary rocks underlie 1 500 000 km^2 of eastern Australia. Depositional environments in them range from freshwater to shallow marine. The Neocomian and Aptian sequences are quartz-rich, and the Albian and Cenomanian sequences are quartz-poor. The older sequences were derived largely from nearby basement rises, while the younger sequences were probably derived from Cretaceous volcanics forming a mountain range to the northeast. Glauconie is common in marine and paralic sequences. An epicontinental sea, with seaways to the north and east, covered the basins in the late Aptian, but the eastern seaway closed during an early Albian regression. A second transgressive-regressive cycle, in the late Albian, was virtually confined to the Eromanga Basin. Collectively the two transgressions and regressions were spread over about 20 million years. The present Baltic Sea is thought to provide a small-scale depositional model for the sequences under consideration: of an epicontinental sea in a cool climate, in which the salinity, the number of planktonic organisms, and the variety of benthonic organisms, decrease away from the ocean. The shallowness of the sea and its entrances mean that it is very susceptible to major environmental changes, caused by such factors as eustatic changes of sea level. The area had a gentle northwesterly regional tilt during the Cretaceous, but mid-Tertiary movements changed this to southwesterly. Despite subsequent erosion, as much as 2000 m of Cretaceous sediment is preserved in the Eromanga Basin, and 700 min the Surat Basin.

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Additional Info

Field Value
Title The Cretaceous of the Eromanga and Surat Basins
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/99f30c0c-db42-42b8-8dbe-c57aa17c2fbc
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        133.0,
        -33.0
      ],
      [
        154.0,
        -33.0
      ],
      [
        154.0,
        -19.0
      ],
      [
        133.0,
        -19.0
      ],
      [
        133.0,
        -33.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "The Cretaceous of the Eromanga and Surat Basins". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/the-cretaceous-of-the-eromanga-and-surat-basins2