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

Isostasy and structure of the lower crust and upper mantle in the Precambrian terrains of northwest Australia, from regional gravity studies

Created 17/10/2025

Updated 17/10/2025

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

Published seismic models for the northwest region of Australia are somewhat at variance with proposed isostatic models for the region. Two density models are examined to explain the difference. In one, the thick, low-density crust of the Yilgarn Craton is compensated at depth by a region of high-density upper mantle rocks, and in the other the composition of the Yilgarn Craton is slightly more iron rich (either at the base or to a lesser extent throughout) than the crust of the Pilbara Craton. A compromise model is preferred in which the crust, particularly in the Yilgarn Craton, is chemically stratified with the denser, more basic rocks at the base. In this model the upper mantle under the Yilgarn Craton is denser than that under the Pilbara Craton and isostatic equilibrium is reached at depths greater than the base of the crust. The differences in the crust or the mantle throughout the region provide more evidence that the cratons had separate evolutionary histories. The upper mantle under the Pilbara Craton may be less dense than that under the Yilgarn Craton because of iron depletion, and may have been the source of iron for the basic volcanics and banded iron formations in the Hamersley Basin, which overlies the Pilbara Craton.

Files and APIs

Tags

Additional Info

Field Value
Title Isostasy and structure of the lower crust and upper mantle in the Precambrian terrains of northwest Australia, from regional gravity studies
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/3750492a-8e9b-435e-9a6d-bc2a23925fd9
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
      ],
      [
        122.0,
        -27.0
      ],
      [
        122.0,
        -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 "Isostasy and structure of the lower crust and upper mantle in the Precambrian terrains of northwest Australia, from regional gravity studies". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/isostasy-and-structure-of-the-lower-crust-and-upper-mantle-in-the-precambrian-terrains-of-north