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Deformation of the crust and mantle in central Australia

Created 16/10/2025

Updated 16/10/2025

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Three zones of retrograded crystalline basement rocks have been delineated in central Australia. One, along the southwestern margin of the Amadeus Basin, was deformed about 600 m.y. ago during the Petermann Ranges Orogeny. Two one north of the Amadeus Basin, the other north of the Ngalia Basin were deformed during the Carboniferous Alice Springs Orogeny. Each retrograded zone is highly deformed and is flanked on one side by folded and thrust sedimentary rocks and on the other by granulite and amphibolite facies rocks. The high-grade rocks appear to have resulted from several metamorphic episodes in the Precambrian. A major gravity gradient is associated with each retrograded zone; the Bouguer anomaly highs generally occur over the areas of high-grade metamorphic rocks, and the lows over the sedimentary basins and retrograded rocks. In general, the deformed and retrograded zones are moderately to gently dipping. The gravity gradients are so wide and steep that to explain them the deformed zones must pass through the crust into the mantle beneath. The crust and mantle above each deformed zone have been upthrust, bringing granulite facies rocks to the surface and producing Bouguer gravity anomaly highs over the uplifted lower crust and mantle. The deformed zones are similar to the subduction zones that may develop on the margins of continents, but there is no evidence of continental collision in central Australia when they were formed, and they are regarded rather as possible examples of intracontinental plate reactions. They may have extended right across the continent or may terminate against strike-slip (transform) faults. A possible site for such a transform fault in Western Australia is discussed, but its existence is speculative.

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Field Value
Title Deformation of the crust and mantle in central Australia
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/8669cff0-22c7-4867-b688-1d4b279442b5
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        129.0,
        -28.0
      ],
      [
        135.0,
        -28.0
      ],
      [
        135.0,
        -26.0
      ],
      [
        129.0,
        -26.0
      ],
      [
        129.0,
        -28.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "Deformation of the crust and mantle in central Australia". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/deformation-of-the-crust-and-mantle-in-central-australia