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 SA AIG Geopub June 2023Talk TitleRare earth enrichment in lacustrine sedimentary clays – REE source and enrichment mechanisms at Koppamurra, S.A.
Stefan Löhr, Research Associate, University of Adelaide
The deposits of South China, formed following prolonged (sub)tropical weathering of rare earth element (REE)-enriched igneous parent rocks, have long served as the type example of clay-hosted REE deposits. Discoveries of similar deposits in Asia, Africa and South America have reinforced the view that these characteristics are universally applicable. In contrast, the recently discovered Koppamurra deposit of South Australia is developed within a <10 m thick sequence of young (1-2 Myrs), clay-rich lake sediments. These directly overlie a deeply weathered but REE-poor marine limestone, and there is no obvious igneous REE source in the region. This points to as-yet unrecognized processes that allow rapid REE enrichment in a broader range of settings than is currently appreciated. Join us as Stefan explores the REE source, host phases and enrichment mechanisms of the Koppamurra deposit. PresenterStefan Löhr, Research Associate Stefan Löhr is an Earth Scientist with a broad range of interests, mostly involving the sedimentary record in one way or another. He has recently returned to the University of Adelaide after seven years at Macquarie University. Current research spans topics such as palaeo-reconstructions across major environmental perturbations, or secondary mineral formation and alteration in terrestrial and marine settings and their role in biogeochemical cycling in the past and present. Most recently he has combined his expertise in clay mineralogy, (isotope) geochemistry and high resolution sedimentary petrography to identify the mechanisms controlling REE mobilisation and enrichment in marine and terrestrial clays.
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