| Title | Discussion on "Syn-metamorphic sulfidation of the Gamsberg zinc deposit, South Africa" by Stefan Höhn, Hartwig E. Frimmel, and Westley Price |
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| Author | Cawood, T K ;
Rozendaal, A; Spry, P G |
| Source | Mineralogy and Petrology 2023 p. 1-11, https://doi.org/10.1007/s00710-023-00821-6 |
| Image |  |
| Year | 2023 |
| Alt Series | Natural Resources Canada, Contribution Series 20230120 |
| Publisher | Springer Nature |
| Document | serial |
| Lang. | English |
| Media | paper; digital; on-line |
| File format | pdf |
| Area | South Africa |
| Subjects | mineral deposits; zinc; metamorphism; clastics |
| Illustrations | tables; location maps |
| Released | 2023 04 21 |
| Abstract | Höhn et al. (2021) proposed that the giant Gamsberg Zn deposit, South Africa, initially formed as a sedimentary exhalative (SEDEX) deposit during the Mesoproterozoic and was subsequently oxidized near
surface. The oxidized ore was then supposedly sulfidized by sulfur-rich metamorphic fluids during and after upper amphibolite facies metamorphism. We view this model as untenable for various reasons and suggest that the Gamsberg deposit and others in
the Aggeneys-Gamsberg district (Swartberg, Broken Hill-Deeps, Big Syncline) are metamorphosed clastic SEDEX deposits rather than having formed by synmetamorphic sulfidation processes. |
| Summary | (Plain Language Summary, not published)
The giant Gamsberg deposit in South Africa, along with several other deposits in the district (Swartberg, Broken Hill-Deeps, and Big Syncline), contains
sulfide minerals with copper, lead, zinc, and silver. Scientists generally think that these deposits were formed on (or just below) the seafloor millions of years ago, from hot water carrying dissolved metals. However, the deposits have several
unusual characteristics that make them look different to typical seafloor deposits. In a recent study, Höhn and others suggest that these unusual characteristics are because the deposits were formed and buried, but were then oxidized (rusted) when
they were exposed on surface again due to erosion, before being buried again and affected by sulfur-rich fluids. We disagree with their model. In this paper, we outline our reasons for disagreeing, and provide support for the more traditional idea
that the unusual characteristics of these deposits are simply due to them being subjected to heat and pressure when they were buried. |
| GEOSCAN ID | 331995 |
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