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Short-range gold mobilisation in palaeoplacer deposits

  • Hartwig E. Frimmel
  • W. E. Lawrie Minter
  • John Chesley
  • Jason Kirk
  • Joaquin Ruiz
Conference paper

Abstract

A comparative study of the morphology of gold particles within fluvial conglomerates of the Archaean Witwatersrand and the Palaeoproterozoic Roraima Supergroups revealed the presence of two gold generations: an older with variable degree of rounding and evidence of mechanical abrasion, and a younger one typified by well crystallised, euhedral overgrowths. This is in spite of a contrasting chemical milieu during post-depositional alteration and indicates mobilisation of detrital gold on a microscopic scale. Unusually high Os concentrations, typical of Witwatersrand gold, were found in both well rounded and secondary gold particles, which is best explained by very short-range gold mobilisation during post-depositional alteration, thus supporting a modified palaeoplacer model for the Witwatersrand deposits.

Keywords

Gold palaeoplacer Witwatersrand Roraima short-range mobilization 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2005

Authors and Affiliations

  • Hartwig E. Frimmel
    • 1
    • 2
  • W. E. Lawrie Minter
    • 3
  • John Chesley
    • 4
  • Jason Kirk
    • 4
  • Joaquin Ruiz
    • 4
  1. 1.Dept. of Geological SciencesUniversity of Cape TownRondeboschSouth Africa
  2. 2.Institute of MineralogyUniversity of WürzburgAm HublandWürzburg
  3. 3.Goldstone ResourcesConstantiaSouth Africa
  4. 4.Department of GeosciencesUniversity of ArizonaTucsonUSA

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