Southwest Yilgarn 3D Geomodel 2021

Screenshot of the Southwest Yilgarn 3D Geomodel
Screenshot of the Southwest Yilgarn 3D Geomodel

A 3D compilation, aimed at assisting with the visualisation of data (map, section and 3D) for the region, has used selected datasets from the Southwest Yilgarn Accelerated Geoscience Program (AGP). Some of the datasets in the 3D project include:

  • The new 1:100 00k geology, structure and dyke layers
  • Extracts from the state potential field grids 
  • Three P-wave velocity profiles (AOB_velocity, Perth_Jubilee_velocity, Perth_Albany_velocity) (Dentith et al., 2000; Mathur et al., 1969)
  • The reprocessed New Norcia seismic reflection data (New_Norcia _seismic_data_shallow)
  • Multiscale edges from gravity data (worms) 

A prominent feature of the southwest Yilgarn Craton is a large (~ 55 000 km2), long-wavelength, Bouguer gravity high. The eastern edge of this anomaly has a distinct northwest trend that has been named the Yandanooka/Cape Riche Lineament (Everingham, 1965). To improve our understanding of the source of this gravity anomaly, 2D gravity forward modelling and 3D gravity inversions were done.
Some of the density modelling in the 3D project include:

  • The P-wave velocity model of Dentith et al. (2000) has been converted to density and modified to fit the long wavelength gravity data, using gravity forward modelling
  • 3D density models from gravity inversion, in Geosoft’s VOXI Earth Modeller

Dentith, MC, Dent, VF and Drummond, BJ 2000, Deep crustal structure in the southwestern Yilgarn Craton, Western Australia: Tectonophysics, v. 325, p. 227–255.
Everingham, IB 1965, The crustal structure of the south-west of Western Australia: Bureau of Mineral Resources, Geology and Geophyiscs, Record 1965/97.
Mathur, SP, Moss, FJ and Branson JC 1969, Seismic and gravity investigation along the geotraverse, Western Australia, 1969: Bureau of Mineral Resources, Geology and Geophysics, Bulletin 191, 69p.

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