Syn-metamorphic sulfidation of the Gamsberg zinc deposit, South Africa

Höhn, Stefan; Frimmel, Hartwig E.; Price, Westley

doi:10.1007/s00710-021-00764-w

Cited by 7 publications

(2 citation statements)

References 44 publications

(61 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Mesoproterozoic Aggeneys-Gamsberg ore district hosts one of the world's largest sulfidic base metal complex, classified as a Broken Hill-type base metal deposit which are traditionally interpreted as metamorphosed sedimentary exhalative (SEDEX) deposits (Höhn et al 2021b;Rozendaal et al 2017;Stalder and Rozendaal 2005). Recent investigations support the hypothesis that the massive sulfide deposits in the Aggeneys district show a more complex history, after initial SEDEX-type mineralization near-surface oxidation and sulfidation of the oxidized ore during medium-to high-grade metamorphism took place (Willner et al 1990;Höhn et al 2021a).…”

Section: Geological Settingmentioning

confidence: 99%

Implications of new hyperspectral satellites for raw materials exploration

2022

View full text Add to dashboard Cite

Hyperspectral remote sensing already is important in geoscientific research in the fields of geology, soil, exploration and mining. New hyperspectral satellite systems are already in operation (e.g. PRISMA and DESIS; Caporusso et al. 2020; Alonso et al. (Sensors 19(20):4471–4515, 2019)) and more systems are planned e.g. the European Copernicus Next Generation Hyperspectral Satellite CHIME (Nieke and Rast 2018). The German system EnMAP was successfully launched into space on 1st of April 2022 (DLR 2022). The potential of hyperspectral airborne and satellite borne data for mining-related applications is discussed. Investigated are the information contents of hyperspectral data for exploration target recognition and their dependency on spatial resolutions of different sensor platforms. Airborne data offer high spatial resolution of 2.5 m with limited areal data acquisition, whereas hyperspectral spaceborne sensors guaranty nearly worldwide data availability with the same spectral characteristics but medium spatial resolution (30 m). The aspects of high spectral resolution and high versus medium spatial resolution targeted mineral mapping is investigated. The methodological concept includes processing aspects, standardized data availability for mineral mapping and mineralization targeting for operational application, to maintain/allow application of hyperspectral data even for non-remote sensing experts. Based on hyperspectral airborne data acquired in the Aggeneys region in South Africa, spaceborne hyperspectral data are simulated following the EnMAP specifications, and the concept for targeted mapping of surface alterations of a lead zinc deposit is discussed.

show abstract

Section: Geological Settingmentioning

confidence: 99%

Implications of new hyperspectral satellites for raw materials exploration

2022

View full text Add to dashboard Cite

show abstract

“…Hons thesis, Univ. Adelaide, 2011); 2 -Mt Isa Cu-Pb-Zn (Sedex) deposit (Cave et al 2020); 3 -Gamsberg Zn (Sedex) deposit (Höhn et al 2021); 4 -Bukit Botol (VMS) deposit, massive sulfides (Basori et al 2021); 5 -Bukit Botol (VMS) deposit, vein sulfides (Basori et al 2021); 6 -Bankshapa VMS deposit (Mishra et al 2021); 7 -Jangaldheri VMS deposit (Mishra et al 2021); 8 -Biskan VMS deposit (Mishra et al 2021).…”

Section: C Cd Zn and S Isotopes And The Origin Of Broken Hill And Min...mentioning

confidence: 99%

Zinc, sulfur and cadmium isotopes and Zn/Cd ratios as indicators of the origin of the supergiant Broken Hill Pb–Zn–Ag deposit and other Broken Hill-type deposits, New South Wales, Australia

Spry

Mathur

Teale³

et al. 2022

Geol. Mag.

View full text Add to dashboard Cite

Various genetic models have been proposed for the supergiant Proterozoic Broken Hill Pb–Zn–Ag deposit largely based on geological and geochronological evidence. Here we present Zn, Cd and S isotope compositions as well as Zn/Cd ratios of sphalerite from Broken Hill and minor Broken Hill-type deposits (Australia) to help constrain these models but focus on syngenetic and magmatic–hydrothermal processes, since epigenetic models can be rejected because the orebodies were deformed and metamorphosed by the Olarian Orogeny. Values of δ34SVCDT, δ66ZnAA-ETH and δ114CdNIST SRM 3108 for sphalerite from Broken Hill range from +0.27 to +4.73 ‰, −1.15 to +0.46 ‰ and −0.48 to +0.01 ‰, respectively, while those for the smaller Broken Hill-type deposits range from −5.11 to +1.28 ‰, −0.97 to +0.10 ‰ and −1.02 to +2.59 ‰, respectively. By combining published S isotope data of sulfides from the Broken Hill district with those obtained here, the sources of sulfur via thermochemical sulfate reduction, bacterial sulfate reduction and a magmatic origin cannot be distinguished. However, when the S isotope compositions are considered along with the broad range of Cd and Zn isotope data for sphalerite, which are among the lightest and heaviest yet reported for a sulfide deposit, the isotopic datasets are consistent with low-temperature biogenic processes associated with syngenetic deposition of sulfides. Cadmium isotope compositions when coupled with Zn/Cd ratios of sphalerite have previously been used to classify Pb–Zn deposits, including low-temperature, high-temperature and exhalative ores. However, the Zn/Cd ratios of sphalerite from Broken Hill cannot be used for such classification purposes.

show abstract

Sulfide anatexis during high-grade metamorphism: a case study from the Bodenmais SEDEX deposit, Germany

2023

View full text Add to dashboard Cite

Many sedimentary-exhalative (SEDEX) sulfide deposits have been subject to regional metamorphism and, if the metamorphic grade was high enough, this could have resulted in sulfide anatexis. Although experiments and textures indeed showed that some deposits were partially molten, there is an ongoing debate as to the extent to which metamorphosed ore deposits were molten. Since some SEDEX deposits underwent amphibolite to granulite facies metamorphism, not only sulfides but also the host silicate rocks should have reached anatectic conditions. Due to the two immiscible silicate and sulfide melts, the formation of typical mingling and emulsion textures, as already known from magmatic sulfide deposits, should form. To test this hypothesis, we investigate sulfide-silicate textures from the granulite-facies Bodenmais SEDEX deposit (Germany). Textures from Bodenmais are similar to magmatic sulfide deposits including sulfide-matrix breccia, emulsion textures, pegmatitic leucosomes, and massive sulfides overlain by net-textured intergrowths of refractory quartz, which is interpreted to be a relic of silicate anatexis. Minerals crystallized during the interaction of both immiscible melts differ in their chemistry compared to the same minerals found in the adjacent migmatitic host rocks: for example, garnet in sulfides is Mn-rich (spessartine), but Fe-rich (almandine) in the migmatites and sulfide-enclosed cordierite is more enriched in Mg (Mg/(Mg + Fe): 0.84) than migmatitic cordierite (Mg/(Mg + Fe): 0.54). The textures themselves, their spatial arrangement within the deposit, the differences in mineral chemistry, and the observed crystallization sequence provide unequivocal evidence that the sulfides at Bodenmais were molten to a large extent under granulite facies conditions.

show abstract

Syn-metamorphic sulfidation of the Gamsberg zinc deposit, South Africa

Cited by 7 publications

References 44 publications

Implications of new hyperspectral satellites for raw materials exploration

Implications of new hyperspectral satellites for raw materials exploration

Zinc, sulfur and cadmium isotopes and Zn/Cd ratios as indicators of the origin of the supergiant Broken Hill Pb–Zn–Ag deposit and other Broken Hill-type deposits, New South Wales, Australia

Sulfide anatexis during high-grade metamorphism: a case study from the Bodenmais SEDEX deposit, Germany

Contact Info

Product

Resources

About