1887
Volume 24, Issue 3-4
  • ISSN: 0812-3985
  • E-ISSN: 1834-7533

Abstract

Analysis of regional aeromagnetic and gravity data sets shows that the Stuart Shelf is host to a major volcano-plutonic complex consisting of large volumes of felsic-dominated volcanic rocks and shallow-crustal level granitic bodies. The complex is interpreted as a major eruptive centre associated with the Gawler Range volcano-plutonic event of 1600 Ma to 1580 Ma. The mid-Proterozoic basement surface in the northern and central areas of the Stuart Shelf lies beneath a thick cover of younger sediments and is interpreted as representing a section through the lower-middle levels of the volcano-plutonic complex. Volcano-plutonic elements present at this stratigraphic level include collapsed cauldrons, epizonal granites, and ring faults associated with pluton emplacement. Some of these structures acted as fluid pathways during an extensive period of Fe-metasomatism associated with the volcano-plutonic event, and consequently are evident in the geophysical data as gravity and/or magnetic highs resulting from localised deposits of magnetite and hematite. The Stuart Shelf is a prime example of a terrane where the geophysical response is dominated by secondary alteration assemblages rather than primary lithologies. The presence of a thick cover sequence over the entire Stuart Shelf restricts direct examination of the volcano-plutonic complex. However, comparison of the geophysical data from the Stuart Shelf with data from well-exposed, well-documented terranes of a similar tectonic setting provides a useful insight into the possible structural and tectonic history of the Stuart Shelf. Such terranes include the mid-Proterozoic St. Francois Mountains of south-east Missouri and the Quaternary volcanic provinces of the mid-western United States of America.

© 1993 ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG993513
1993-09-01
2026-01-17

  • From This Site

    /content/journals/10.1071/EG993513
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Alatorre-Zamora, M.A. and Campos-Enriquez, J.O. (1991), ‘La Primavera caldera (Mexico): Structure inferred from gravity and hydrogeological considerations’, Geophysics56, 992–1002.
  2. Anderson, C.G. (1980), ‘Magnetic and gravity interpretation on the Stuart Shelf’, Bulletin of the Australian Society of Explor. Geophys.11, 115–120.
  3. Branch, C.D. (1978), ‘Evolution of the Middle Proterozoic Chandabooka Caldera, Gawler Range acid volcano-plutonic province, South Australia’, Journal of the Geological Society of Australia25, 108–123.
  4. Carle, S.F. (1988), ‘Three-dimensional gravity modelling of the geologic structure of Long Valley Caldera’, J. Geophys. Res.93, 13237–13250.
  5. Christianson, R.L., Lipman, P.W., Carr, W.J., Byers, F.M., Orkild, P.P. and Sargent, K.A. (1977), ‘Timber Mountain – Oasis Valley caldera complex of southern Nevada’, Geological Society of America Bulletin88, 943–959.
  6. Cordell, L. and Knepper, D.H. (1987), ‘Aeromagnetic images: Fresh insight to the buried basement, Rolla quadrangle, southeast Missouri’, Geophysics52, 218–231.
  7. Creaser, R.A. (1989), ‘The geology and petrology of Middle Proterozoic felsic magmatism of the Stuart Shelf, South Australia’, PhD thesis, Latrobe Univ., Melbourne, (unpubl.).
  8. Creaser, R.A. and Cooper, J.A. (1993), ‘U-Pb geochronology of Middle Proterozoic felsic magmatism surrounding the Olympic Dam Cu-U-Au-Ag and Moonta Cu-Au-Ag deposits, South Australia’, Economic Geology88, 186–197.
  9. Dalgarno, R. (1986), ‘Tectonic history of the Stuart Shelf’, in Excursion Guide, Eighth Australian Geological Convention, Geol. Soc. Aust., Sydney.
  10. Davidson, G.J. and Paterson, H.L. (1993), ‘Oak Dam East: A prodigious Cu-U-Au bearing Fe-oxide body on the Stuart Shelf, South Aust., Abstracts from the 2nd Nat. Mtg, Spec. Grp. in Econ. Geol., Armidale, February 1993., Geol. Soc. Aust., 18–19.
  11. Dzurisin, D. and Yamashita, K.M. (1987), ‘Vertical surface displacements at Yellowstone Caldera, Wyoming, 1976–1986’, J. Geophys. Res.92, 13753–13766.
  12. Esdale, D.J., Pridmore, D.F., Coggon, J.H., Muir, P.M., Williams, P.K. and Fritz, F.P. (1987), ‘Olympic Dam deposit — geophysical case history’, Explor. Geophys.18, 47–49.
  13. Fanning, C.M., Flint, R.B. and Preiss, W.V. (1983), ‘Geochronology of the Pandurra Formation’, Quarterly Geological Notes, Geological Survey of South Australia88, 11–16.
  14. Giles, C.W. (1988), ‘Petrogenesis of the Proterozoic Gawler Range Volcanics, South Australia’, Precambrian Research40/41, 407–427.
  15. Giles, C.W. and Teale, G.S. (1979), ‘The geochemistry of Proterozoic acid volcanics from the Frome Basin’, Quarterly Geological Notes, Geological Survey of South Australia71, 13–18.
  16. Hauck, S.A. (1988), ‘Petrogenesis and tectonic setting of Middle Proterozoic iron oxide-rich ore deposits — An ore deposit model for Olympic Dam-type mineralization’, in Pratt, W.P. and Sims, P.K. (Eds) The Midcontinent of the United States – Permissive Terrane for an Olympic Dam-Type Deposit?, United States Geological Survey Bulletin1932, 4–39.
  17. Houseman, G.A., Cull, J.P., Muir, P.M. and Paterson, H.L. (1989), ‘Geothermal signatures and uranium ore deposits on the Stuart Shelf of South Australia’, Geophysics54, 158–170.
  18. Johnson, J.P. and Cross, K.C. (1991), ‘Geochronological constraints on the genesis of the Olympic Dam Cu-U-Au-Ag deposit, South Australia’, Fluid Flow Meeting, Canberra, BMR.
  19. Kisvarsanyi, E.B. (1988), ‘General features of the St. Francois and Spavinaw Granite-Rhyolite Terranes and the Precambrian metallogenic region of southeast Missouri’, in Pratt, W.P. and Sims, P.K. (Eds) The Midcontinent of the United States – Permissive Terrane for an Olympic Dam-Type Deposit?, United States Geological Survey Bulletin1932, 48–57.
  20. Lambert, I.B., Knutson, J., Donnelly, T.H. and Etminan, H. (1987), ‘Stuart Shelf-Adelaide Geosyncline copper province, South Australia’, Economic Geology82, 108–123.
  21. Marsh, B.D. (1984), ‘On the mechanics of caldera resurgence’, J. Geophys. Res.89, 8245–8251.
  22. Morgan, L.A., Doherty, D.J. and Leeman, W.P. (1984), ‘Ignimbrites of the eastern Snake River Plain: Evidence for caldera-forming eruptions’, J. Geophys. Res.89, 8665–8678.
  23. Oreskes, N. and Einaudi, M.T. (1990), ‘Origin of rare earth element-enriched hematite breccias at the Olympic Dam Cu-U-Au-Ag deposit, Roxby Downs, South Australia’, Economic Geology85, 1–28.
  24. Parker, A.J. (1990), ‘Gawler Craton and Stuart Shelf — regional geology and mineralisation’, in Hughes, F.E. (Ed.) Geology of the Mineral Deposits of Australia and Papua New Guinea, The Australasian Institute of Mining and Metallurgy, Melbourne, 999–1008.
  25. Paterson, H.L. and Muir, P.M. (1986), ‘Exploration Licence 1316 (Part) — Stuart Shelf — relinquishment report’, South Australian Department of Mines and Energy, Open File Env. 6562 (unpubl.).
  26. Pirajno, F. (1992), Hydrothermal mineral deposits, Springer-Verlag, Berlin.
  27. Pitcher, W.S. (1979), ‘The nature, ascent and emplacement of granitic magmas,’ Journal of the Geological Society of London136, 627–662.
  28. Sheard, S.N. and Binks, P.J. (1987), ‘An exploration case study for Olympic Dam style mineralization on the Stuart Shelf, S.A.’, Explor. Geophys.18, 202–204.
  29. Sides, J.R., Bickford, M.E., Shuster, R.D., Nusbaum, R.L. (1981), ‘Calderas in the Precambrian terrane of the St. Francois Mountains, southeastern Missouri’, J. Geophy. Res.86, 10349–10364.
  30. Tonkin, D.G. (1986), ‘Structural outline of the Stuart Shelf’, in Excursion Guide, Eighth Australian Geological Convention, Geol. Soc. of Aust., Sydney.
  31. Tucker, D.H. and Nelson, R.G. (1991), ‘Interpretation and exploration significance of the 1988 Eyre Peninsula airborne magnetic survey, South Australia’, Conf. Abstracts, 8th ASEG Conf. and Exhib., Sydney.
  32. Wood, C.A. (1984), ‘Calderas: a planetary perspective’, J. Geophys. Res.89, 8391–8406.
/content/journals/10.1071/EG993513
Loading
  • Article Type: Research Article
Keyword(s): aeromagnetics; gravity; Olympic Dam; Stuart Shelf; volcanic

Most Cited This Month Most Cited RSS feed

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error