From Geoscience Australia
JSON format icon JSON RDF format icon RDF ISO19115-3 XML

A crustal profile across the Archaean Pilbara and northern Yilgarn cratons, northwest Australia

Created 17/10/2025

Updated 17/10/2025

JSON format icon JSON RDF format icon RDF ISO19115-3 XML

Two Archaean cratons are exposed in the Precambrian shield of Western Australia: the Pilbara in the north and the Yilgarn in the south. They are separated by the Capricorn Orogen. Seismic recordings of quarry blasts in the north of the West Australian shield indicate that the upper crustal rocks have seismic velocities of 6.0 km s^-1, and are probably of acid to intermediate chemical composition. They overlie a lower crust, presumed to be granulitic, which has a seismic velocity of 6.4 km s^-1 at 13 km depth in the north of the Pilbara Craton and 16 km in the north of the Yilgarn Craton. The northern Yilgarn has a third layer, with a seismic velocity of about 7.0 km s^-1, at the base of the crust. This may represent a higher grade (eclogite?) phase, or it may indicate injection of basic material into the base of the crust. The crust-mantle boundary at the base of the Pilbara Craton and Capricorn Orogen appears to be transitional - it shows velocity gradients rather than a first-order velocity discontinuity. Within the Pilbara Craton, the crust is about 28 km thick in the north and 33 km in the south. South of the Pilbara Craton, the crust thickens under the Capricorn Orogenic Belt, and again under the northern Yilgarn Craton where it is 52 km thick. The form of the structures in the zone of thickening cannot be determined uniquely from the present data. Three models incorporating faults or monoclines and a wedge of 7.0 km s^-1 material at the base of the crust have been derived. The different crustal thicknesses of the cratons suggest that they formed separately and were then tilted towards the Orogenic Belt.

Files and APIs

Tags

Additional Info

Field Value
Title A crustal profile across the Archaean Pilbara and northern Yilgarn cratons, northwest Australia
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/0aa39b8b-3731-4a28-8952-70fa5f52be77
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
{
  "coordinates": [
    [
      [
        115.0,
        -27.0
      ],
      [
        121.0,
        -27.0
      ],
      [
        121.0,
        -20.0
      ],
      [
        115.0,
        -20.0
      ],
      [
        115.0,
        -27.0
      ]
    ]
  ],
  "type": "Polygon"
}
Data Portal Geoscience Australia

Data Source

This dataset was originally found on Geoscience Australia "A crustal profile across the Archaean Pilbara and northern Yilgarn cratons, northwest Australia". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/a-crustal-profile-across-the-archaean-pilbara-and-northern-yilgarn-cratons-northwest-australia