Mineralium Deposita

, Volume 39, Issue 5–6, pp 632–645 | Cite as

Carbonate alteration of the Upper Mount McRae Shale beneath the martite-microplaty hematite ore deposit at Mount Whaleback, Western Australia

  • Adam D. WebbEmail author
  • Gerald R. Dickens
  • Nicholas H. S. Oliver


The formation of large martite-microplaty hematite ore deposits in northwest Australia remains a contentious topic in part because important evidence supporting a unifying genetic model has not been observed at all deposits. Carbonate replacement of silica has been found along normal faults below ore at the Mount Tom Price and Giles Mini deposits, which suggests an early hypogene process during ore formation. However, such rocks have not been identified at the largest martite-microplaty hematite deposit, Mount Whaleback. In this study, samples of the Mount McRae Shale are examined for their chemistry, mineralogy and petrography. These samples were collected from several key locations, including an area that immediately underlies ore along the Mount Whaleback fault at Mount Whaleback. Compared to unaltered black Mount McRae Shale from Wittenoom Gorge in the north and altered black and red Mount McRae Shale at Mount Whaleback, reddish-green Mount McRae Shale along the Mount Whaleback fault is greatly enriched in MgO and CaO and depleted in SiO2. This chemistry arises from significant amounts of fine- to medium-grained ferroan-dolomite and ankerite and cross-cutting chlorite and carbonate veins. The composition is distinct from that produced during regional metamorphism, and most likely represents hydrothermal alteration after metamorphism. The lack of carbonate-rich, silica-poor rocks in the overlying Dales Gorge Member at Mount Whaleback is consistent with pervasive oxidation of most rocks in the region during or after ore genesis, a process that removed carbonates. Although several questions remain unanswered, these results support models that invoke an early hypogene stage during the formation of the martite-microplaty hematite deposits in the Hamersley Province.


Martite-microplaty hematite ore deposits Northwest Australia Carbonate replacement of silica Chemistry, mineralogy and petrography Hypogene stage 



This research was funded through an ARC Large Grant to N.H.S. Oliver and G.R. Dickens. We gratefully acknowledge BHP Billiton Iron Ore and its geologists, particularly Simon Hewson, Peter Croft, Peter Waters, Mal Kneeshaw and Mawson Croaker, for providing access to samples and data at Mount Whaleback and other logistical support. However, our interpretation of the data does not necessarily reflect the opinions of BHPBIO. We also thank Elvy Grigolato, Kevin Blake and Sharon Ness of the JCU-AAC for help with the XRF, XRD and electron-microprobe analyses. Steffen Hagemann, Alexandre Raphael Cabral and an anonymous reviewer are thanked for their detailed and insightful review comments.


  1. Barley ME, Pickard AL, Hagemann SG, Folkert SL (1999) Hydrothermal origin for the 2 billion year old Mount Tom Price giant iron ore deposit, Hamersley Province, Western Australia. Miner Deposita 34:784–789CrossRefGoogle Scholar
  2. Brown MC, Oliver NHS, Dickens GR (2004) The characterization and paragenesis of veining and fluid flow in the Mount Whaleback iron ore district, eastern Hamersley Province, Western Australia. Precamb Res 128:441–474CrossRefGoogle Scholar
  3. Dalstra HJ, Harding AE, Taylor D (2002a) Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia – A reply. Econ Geol 97:174–176Google Scholar
  4. Dalstra HJ, Harding AE, Riggs T, Taylor D (2002b) Banded iron-formation hosted high-grade hematite deposits, a coherent group? Proceedings of Iron Ore 2002 Conference, 9–11 September 2002, Perth, Western Australia. Special AusIMM Publication Series No. 7/2002, pp 41–56Google Scholar
  5. Deer WA, Howie RA, Zussman J (1992) The rock forming minerals. Longman, London, pp 1–696Google Scholar
  6. Hagemann SG, Barley ME, Folkert SL (1999) A hydrothermal origin for the giant BIF-hosted Tom Price iron ore deposit. In: Stanley CJ et al. (eds) Mineral Deposits, Processes to Processing. Balkemia, Rotterdam, pp 41–44Google Scholar
  7. Harmsworth RA, Kneeshaw M, Morris RC, Robinson CJ, Shrivastava PK (1990) BIF-Derived Iron Ores of the Hamersley Province. In: Hughes FE (ed) Geology of the mineral deposits of Australia and Papua New Guinea. Australasian Institute of Mining and Metallurgy, Melbourne, pp 617–642Google Scholar
  8. Kneeshaw M, Kepert DA (2002) Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia – A discussion. Econ Geol 97:173Google Scholar
  9. Macleod WN (1966) The geology and iron deposits of the Hamersley Range area, Western Australia. Geol Surv West Aust Bull, 117Google Scholar
  10. Martin DM, Li ZX, Nemchin AA, Powell CM (1998) A pre-2.2 Ga age for giant hematite ores of the Hamersley Province, Australia. Econ Geol 93:1084–1090Google Scholar
  11. Morris RC (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 75:185–209Google Scholar
  12. Morris RC (1985) Genesis of iron ore in banded iron formation by supergene and supergene-metamorphic processes, A conceptual model. In: Wolf KH (ed) Handbook of strata-bound and stratiform ore deposits, Vol. 13. Elsevier, Amsterdam, pp 73–235Google Scholar
  13. Morris RC (2002a) Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia – A discussion. Econ Geol 97:177–178Google Scholar
  14. Morris RC (2002b) Iron ore genesis and post-ore metasomatism at Mount Tom Price. Proceedings of Iron Ore 2002 Conference, 9–11 September, 2002, Perth, Western Australia. Special AusIMM Publication Series No 7/2002, pp 3–13Google Scholar
  15. Munsell AH (1966) The Munsell Book of Color. MacBeth Color and Photometry. Kollmorgen Corporation, Newburgh, New YorkGoogle Scholar
  16. Oliver NHS, Dickens GR (1999) Hematite ores of Australia formed by syntectonic heated meteoric fluids. In: Stanley CJ et al. (eds) Mineral Deposits, Processes to Processing. Balkemia, Rotterdam, pp 889–892Google Scholar
  17. Powell C McA, Oliver NHS, Li ZX, Martin D McB, Ronaszeki J (1999) Synorogenic hydrothermal origin for giant Hamersley iron oxide ore bodies. Geology 27:175–178CrossRefGoogle Scholar
  18. Ronaszecki J (1992) Structural geology and its controls on iron mineralization at the Mount Whaleback mine, Newman, Western Australia: Guide to the Mount Whaleback stops of the excursion to the southern Pilbara Craton. Geol Soc Australia, May 11–17, 1992, unpublished field guide, pp 1–41Google Scholar
  19. Smith RE, Perdrix JL, Parks TC (1982) Burial metamorphism in the Hamersley Basin, Western Australia. J Petrology 23:75–102Google Scholar
  20. Taylor D, Dalstra HJ, Harding AE, Broadbent GC, Barley ME (2001) Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia. Econ Geol 96:837–873Google Scholar
  21. Taylor D, Dalstra HJ, Harding AE (2002) Genesis of high-grade hematite orebodies of the Hamersley Province, Western Australia – A reply. Econ Geol 97:179–181Google Scholar
  22. Trendall AF, Blockley JG (1970) The iron formations of the Precambrian Hamersley Group, Western Australia, with special reference to the associated crocidolite. Geol Surv West Aust Bull 119, 365 ppGoogle Scholar
  23. Tyler IM, Thorne AM (1990) The northern margin of the Capricorn Orogen, Western Australia – an example of an Early Proterozoic collision zone. J Struct Geol 12:685–701CrossRefGoogle Scholar
  24. Webb AD, Dickens GR, Oliver NHS (2003) From banded iron-formation to iron ore: geochemical and mineralogical constraints from across the Hamersley Province, Western Australia. Chem Geol 197:215–251CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Adam D. Webb
    • 1
    Email author
  • Gerald R. Dickens
    • 1
    • 2
  • Nicholas H. S. Oliver
    • 1
  1. 1.School of Earth SciencesJames Cook UniversityTownsvilleAustralia
  2. 2.Department of Earth SciencesRice UniversityHoustonUSA

Personalised recommendations