Abundant sulphate in the Neoproterozoic ocean: implications of constant δ34S of barite in the Aberfeldy SEDEX deposits, Scottish Dalradian
Published:January 01, 2015
Norman R. Moles, Adrian J. Boyce, Anthony E. Fallick, 2015. "Abundant sulphate in the Neoproterozoic ocean: implications of constant δ34S of barite in the Aberfeldy SEDEX deposits, Scottish Dalradian", Ore Deposits in an Evolving Earth, G. R. T. Jenkin, P. A. J. Lusty, I. Mcdonald, M. P. Smith, A. J. Boyce, J. J. Wilkinson
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The timing and extent of ocean oxygenation is controversial. Proterozoic sulphur isotope datasets often show marked fluctuations over small stratigraphic intervals, suggesting that oceanic sulphate concentrations were much lower than modern values. A large accumulation of Neoproterozoic sulphate (>8 million tonnes preserved), as stratiform barite rock, is located in the Grampian Highlands near Aberfeldy. Diagenetic/metamorphic alteration has caused pronounced δ34S variations near bed margins. This aside, barite throughout the deposits shows a narrow range in δ34S, mean 36±1.5‰. We infer that this is representative of contemporaneous seawater sulphate, and that δ34Sseawater was...
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Ore Deposits in an Evolving Earth
Ore deposits form by a variety of natural processes that concentrate elements into a volume that can be economically mined. Their type, character and abundance reflect the environment in which they formed and thus they preserve key evidence for the evolution of magmatic and tectonic processes, the state of the atmosphere and hydrosphere, and the evolution of life over geological time. This volume presents 13 papers on topical subjects in ore deposit research viewed in the context of Earth evolution. These diverse, yet interlinked, papers cover topics including: controls on the temporal and spatial distribution of ore deposits; the sources of fluid, gold and other components of orogenic gold deposits; the degree of oxygenation in the Neoproterozoic ocean; bacterial immobilization of gold in the semi-arid near-surface environment; and mineral resources for the future, including issues of resource estimation, sustainability of supply and the criticality of certain elements to society.