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

Abstract

Two types of genetic model exist for the enriched ores in the Hamersley Basin: hypogene; and supergene. Although the supergene model has been adopted by a large number of geologists, conflicting geological/geophysical evidence suggests that the other model cannot be ruled out. This paper reports the results of a pilot palaeomagnetic study in and around the Tom Price mine. A negative fold test on results from the Wittenoom Dolomite demonstrates that the Tom Price region underwent an overprint event after folding in the Palaeoproterozoic. The direction of this overprint remanence is similar to that of a previously reported syn-folding remanence found in the Mount Jope Volcanics of the underlying Fortescue Group, and most of the remanence directions reported from the microplaty hematite ore bodies at Tom Price and Paraburdoo. When these results are combined with geological observations, we are led to a tentative interpretation that the enriched ores, particularly the microplaty hematite ores, could have been formed during Palaeoproterozoic extensional deformation, when the tectono/thermal fluids carried the iron to favourable structural positions, and/or leached components other than iron from those structural positions. This tentative model differs from the supergene model in that it requires orogenic/thermal fluids from the deeper sedimentary sequence rather than meteoric fluids percolating down from the weathering surface.

© 1993 ASEG
Loading

Article metrics loading...

/content/journals/10.1071/EG993631
1993-09-01
2026-01-19

  • From This Site

    /content/journals/10.1071/EG993631
    dcterms_title,dcterms_subject,pub_keyword
    -contentType:Journal -contentType:Contributor -contentType:Concept -contentType:Institution
    10
    5
Loading full text...

Full text loading...

References

  1. Clark, D.A. and Schmidt, P.W. (1986), ‘Magnetic properties of the banded-iron formations of the Hamersley Group, W.A.’, CSIRO Division of Mineral Physics: North Ryde (unpublished AMIRA report 1638).
  2. Dorr, J.V.N. (1965), ‘Nature and origin of the high-grade hematite ores of Minas Gerais, Brazil’, Econ. Geol.60, 1–46.
  3. Embleton, B.J.J., Robertson, W.A. and Schmidt, P.W. (1979), ‘A survey of magnetic properties of some rocks from northwestern Australia. Investigation Report 129’, CSIRO Division of Mineral Physics: North Ryde.
  4. Goode, A.D.T. (1981), ‘Proterozoic Geology of Western Australia’, pp. 105–203. In: Hunter, D.R. (Ed.), Precambrian of the Southern Hemisphere, Elsevier, Amsterdam, 882 pp.
  5. Harmsworth, R.A., Kneeshaw, M., Morris, R.C., Robinson, C.J. and Shrivastava, P.K. (1990), ‘BIF-derived iron ores of the Hamersley Province’, pp. 617–642. In: Hughes, F.E. (Ed.), Geology of the mineral deposits of Australia and Papua New Guinea, Australasian Institute of Mining and Metallurgy, Monograph14, Melbourne.
  6. Horwitz, R.C. and Powell, C.McA. (1992), ‘Geological evolution of the southwestern margin of the Hamersley Province’, pp. 43–68. In: Tyler, I.M., Horwitz, R.C. and Powell, C.McA. (Eds), Excursion guide to the southern margin of the Pilbara craton, Specialist Group in Tectonics and Structural Geology, Geol. Soc. Aust.
  7. Kirschvink, J.L. (1980), The least-squares line and plane and the analysis of palaeomagnetic data’, Geophys. J. R. astr. Soc.62, 699–718.
  8. MacLeod, W.N., de la Hunty, L.E., Jones, W.R. and Halligan, R. (1963), ‘A preliminary report on the Hamersley Iron Province, North West Division’, Geol. Survey Western Australia Ann. Rept. 1962, 44–54.
  9. Morris, R.C. (1980), ‘A textural and mineralogical study of the relationship of iron ore to banded iron formation in the Hamersley Iron Province of Western Australia’, Econ. Geol.75, 184–209.
  10. Morris, R.C. (1985), ‘Genesis of iron ore in banded iron formation by supergene and supergene-metamorphic processes — a conceptual model’, pp. 73–235. In: Wolf, K.H. (Ed.), Handbook of strata-bound and stratiform ore deposits, Vol. 13, Elsevier, Amsterdam.
  11. Morris, R.C. (1986), ‘A review of geological research in the iron ore of the Hamersley Iron Province’, pp. 191–200. In: Berkman, D.A. (Ed.), Geology and exploration, Publications of the 13th CMMI Congress, Vol.2, CMMI and AusIMM, Melbourne.
  12. Morris, R.C. (1987), ‘Iron derived by the enrichment of banded iron formation’, pp. 231–267. In: Hein, J.R. (Ed.), The genesis of ores and petroleum associated with sedimentary siliceous deposits, Van Nostrand Reinhold Company, New York.
  13. Powell, C.McA. and Li, Z.X. (1991), ‘New evidence for the age of deformation along the southern margin of the Hamersley Province: relevance to the palaeogeographic evolution and time of iron ore formation’, Geol. Soc. Aust. Abs.31, 52–53.
  14. Porath, H. and Chamalaun, F.H. (1968), ‘Palaeomagnetism of Australian hematite ore bodies — II. Western Australia’, Geophys. J. R. astr. Soc.15, 253–264.
  15. Schmidt, P.W. and Clark, D.A. (1993), ‘Rock magnetism and palaeomagnetism of iron ores and banded iron formations of the Hamersley Group, Western Australia’, Precambrian Res. (in press).
  16. Schmidt, P.W. and Embleton, B.J.J. (1985), ‘Prefolding and overprint magnetic signatures in Precambrian (~2.9-2.7Ga) igneous rocks from the Pilbara Craton and Hamersley Basin, NW Australia’, J. Geophys. Res.90, 2967–2984.
  17. Tyler, I.M. (1990), ‘Mafic dyke swarms’, pp. 191–194. In: Geology and Mineral Resources of Western Australia, Geological Survey of Western Australia Memoir3.
  18. Tyler, I. and Thorne, A.M. (1990), ‘The northern margin of the Capricorn Orogen, Western Australian example of an Early Proterozoic collision zone’, J. Struct. Geol.12, 685–701.
/content/journals/10.1071/EG993631
Loading
  • Article Type: Research Article
Keyword(s): banded-iron formations; Hamersley Basin; iron ores; orogenic fluids; palaeomagnetism; Palaeoproterozoic; Paraburdoo; Tom Price

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