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Cariewerloo Basin Geological Model

Pandurra - Click to enlarge

Using the model
Download the Cariewerloo Basin 3D model
Cariewerloo Basin data release


Similarities between the Athabasca Basin (Saskatchewan Ministry of Energy and Resources website) and Cariewerloo Basin were first proposed by DMITRE geologists (then part of PIRSA) in the 1990s. Subsequently, the uranium potential of the Cariewerloo Basin has been heavily promoted by DMITRE (e.g. Fairclough et al. 2006).

Both are intracratonic basins containing Palaeo-Mesoproterozoic, unmetamorphosed and largely undeformed, quartz dominated, fluvial sedimentary rocks (Jefferson et al. 2007; Cowley 1991).

In addition, both basins unconformably overlie deformed and metamorphosed Palaeoproterozoic and Archaean basement including metasedimentary rocks, such as graphitic schists, and granitoid rocks. Reactivated basement structures that propagate into the basin sediments are also common. Moreover, basement rocks under both basins contain elevated uranium concentrations.

More recent visits by DMITRE geoscientists to Saskatchewan have further delineated the similarities leading to a memorandum of understanding (MoU) being signed in early 2009 between DMITRE's Geological Survey of South Australia (GSSA), and the Saskatchewan Geological Survey, Saskatchewan Ministry of Energy and Resources, Canada. This MoU has resulted in substantial benefits for both parties, throughout the technical phase of this collaboration.

The Cariewerloo Basin hosts the Mesoproterozoic Pandurra Formation, a thick unit of unmetamorphosed, relatively undeformed, dominantly fluvial redbed sediments unconformably overlying the northeastern Gawler Craton. The intracratonic Cariewerloo Basin is currently characterised as an elongate, 120 km wide, NW-trending basin bounded by major NW-trending faults bordering basement highs.

The Cariewerloo Basin 3D Geological Model was developed to assist 3D visualisation and exploration potential of the region for unconformity-related uranium mineralisation. Important aspects of this exploration model are the depth and geometry of the basin-basement surface.

Data from a total of 641 drillholes, lithostratigraphic logging data, HyLogger data and AEM interpretations were used to construct the final model. The model includes the base of Cainozoic, top and base of the Pandurra Formation surfaces, the base of all four informal members within the Pandurra Formation and the top and base of mineral occurrences identified using HyLogger-2TM (dickite, paragonite, illite, muscovite and phengite).

Drillholes, fault networks, images of the drillhole Hyperspectral logs and interpreted lithostratigraphic logs are also included in the 3D environment.

Surfaces derived from HyLogger data showing the distribution of dickite, paragonite, illite, muscovite and phengite have been generated to display geochemical variation across the basin. The sequence of layers is what would be considered an idealised sequence of mineral development with increasing depth due to diagenesis. Each layer was derived from the metres of mineral recorded at each drillhole location and gridded using GIS software. Each mineral has been normalised against the others by matching standard deviations to the maximum standard deviation of the dataset. The implications of these process steps are that the 3D model is not a stratigraphic model and the thicknesses are not on a linear scale. The surfaces display mineralogical trends and highlights spatial relationships in the distribution of these key minerals.

Note the top surface is modelled on the top surface of the Pandurra Formation.

References

Cowley WM 1991. The Pandurra Formation, Report Book 91/7. Department of Mines and Energy South Australia, Adelaide.

Fairclough MC, Fabris A, Hou B and Daly SJ 2006. Uranium: South Australian state of play. MESA Journal 41:8–11. Department of Primary Industries and Resources South Australia, Adelaide.

Jefferson CW, Thomas DJ, Gandhi SS, Ramaekers P, Delaney G, Brisbin D, Cutts C, Portella P and Olson RA 2007. Unconformity-associated uranium deposits of the Athabasca Basin, Saskatchewan Alberta. In CW Jefferson and G Delaney eds, EXTECH IV; Geology and Uranium EXploration and TECHnology of the Proterozoic Athabasca Basin, Saskatchewan and Alberta, Bulletin 588. Geological Survey of Canada, pp. 23–67. (Also: Saskatchewan Geological Society, Special Publication 18; and Geological Association of Canada, Mineral Deposits Division, Special Publication 4.)

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Using the model

In order to increase its accessibility, the Cariewerloo Basin Model has been converted to .pdf format, allowing for maximum portability and eliminating the need for the end user to purchase any specialised software.
 
The user can fully interact with the model using Adobe Acrobat’s 3D Toolbar (Note: the toolbar varies with the version of Acrobat Reader):

  1. Rotate
  2. Spin
  3. Pan
  4. Zoom
  5. Default view
  6. Select view
  7. Toggle model tree
  8. Pause animation
  9. Use orthographic projection
  10. Model render mode
  11. Enable extra lighting
  12. Background colour (disabled if a gradient background is being used)

Adobe Acrobat 3D toolbar

The user can also:

  • Selectively activate and/or deactivate any geological unit, cross section or isopach 
  • Enable geological surfaces to be displayed as transparent, solid or as a solid-wireframe

Software Information
The models can be viewed with Acrobat Reader 9 as it incorporates 3D visualisation capabilities. Acrobat Reader 9 can be downloaded free from the Adobe website.

Download the Cariewerloo Basin 3D Geology Model

 

  • Cariewerloo Basin 3D Geological Model 

 


Note: these models are presented as a 'proof of concept' only and their accuracy (spatial or otherwise) should not be relied upon for exploration or other decision making processes.