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.
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Frimmel, H.E., Minter, W.E.L., Chesley, J., Kirk, J., Ruiz, J. (2005). Short-range gold mobilisation in palaeoplacer deposits. In: Mineral Deposit Research: Meeting the Global Challenge. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-27946-6_243
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DOI: https://doi.org/10.1007/3-540-27946-6_243
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-27945-7
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