Evidence for Palaeozoic hydrothermal remobilization of fluorite mineralization in the Bushveld Igneous Complex, South Africa: insights from Sm-Nd geochronology and (isotope) geochemistry
Jacques G, Henjes-Kunst F, Graupner T, Tardres Z, Avice G, Klemd R (2026)
Publication Type: Journal article
Publication year: 2026
Journal
Book Volume: 242
Article Number: 106250
DOI: 10.1016/j.jafrearsci.2026.106250
Abstract
The world-class Vergenoeg and Buffalo and the Morgenzon fluorite deposits associated with the Bushveld Igneous Complex (South Africa) were studied for their trace element, Sm-Nd and noble gas isotope characteristics. The concordant Sm-Nd isochron ages for Vergenoeg (2050 ± 17 Ma; 2σ) and Buffalo fluorite and igneous rocks indicate derivation from a common isotopically homogeneous source and an igneous origin of the fluorite mineralization at these deposits. The Sm-Nd data for Morgenzon fluorite, however, plot along an errorchron (326 ± 48 Ma; 2σ), reflecting isotopic disturbance. The Morgenzon fluorite is depleted in REE, Y, Th, and U by almost a factor of 100 compared to the Buffalo and Vergenoeg fluorites. Cathodoluminescence (CL) imaging reveals complex internal patterns with a wide range in bluish colours for the Morgenzon fluorite. In contrast, the Buffalo fluorite is quite homogeneous (pale bluish CL colour), indicating a single formation stage. Noble gas (Ne, Xe, Ar) isotope ratios in Vergenoeg and Buffalo fluorites indicate a complex fluid history with a first stage of Archean crustal fluid entrapment, whereas fluorite from Morgenzon shows a much stronger affinity toward modern atmospheric noble gases. Internal dissolution and recrystallisation of the latter fluorite have led to depletion in the abundance of REE, Y, Th, and U and reset of their noble gas and Sm-Nd isotopic systems, possibly by interaction of the fluorite with circulating hydrothermal fluids. Such fluids may have included a glacial meteoric-water component that infiltrated the crust and interacted with the fluorite at Morgenzon in the late Palaeozoic.
Authors with CRIS profile
Involved external institutions
Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)
Germany (DE)
Université Paris Cité
France (FR)
Germany (DE)
Université Paris Cité
France (FR)
How to cite
APA:
Jacques, G., Henjes-Kunst, F., Graupner, T., Tardres, Z., Avice, G., & Klemd, R. (2026). Evidence for Palaeozoic hydrothermal remobilization of fluorite mineralization in the Bushveld Igneous Complex, South Africa: insights from Sm-Nd geochronology and (isotope) geochemistry. Journal of African Earth Sciences, 242. https://doi.org/10.1016/j.jafrearsci.2026.106250
MLA:
Jacques, Guillaume, et al. "Evidence for Palaeozoic hydrothermal remobilization of fluorite mineralization in the Bushveld Igneous Complex, South Africa: insights from Sm-Nd geochronology and (isotope) geochemistry." Journal of African Earth Sciences 242 (2026).
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