The giant Vergenoeg fluorite deposit in a magnetite–fluorite–fayalite REE pipe: a hydrothermally-altered carbonatite-related pegmatoid? (original) (raw)

Summary

The world-class Paleoproterozoic Vergenoeg fluorite deposit in South Africa is hosted in a breccia pipe comprising units with varying proportions of pegmatoidal fayalite, magnetite, fluorite and siderite. The adjacent A-type Bushveld granites also have associated fluorite deposits containing fluorite with similar REE patterns, fluid inclusion and Sr isotope compositions to those at Vergenoeg, leading to the proposal that there is a genetic relationship. This is despite the silica-undersaturated nature (SiO2 < 30%) of the Pipe and its extreme enrichment in Ca, F, Fe, Nb, P and REE compared to granites. Both liquid immiscibility from a granitic melt and granitic magmato-hydrothermal activity have been proposed as genetic mechanisms to explain this exotic composition. However, the Vergenoeg Pipe shows greater similarities to alkaline rocks, in particular the Phalaborwa carbonatite of similar age, including: i) size and shape, ii) associated maars, iii) mineralogical zoning, iv) geochemical, radiogenic and stable isotope composition, and v) presence of both high-T and low-T fluid inclusions. This suggests an alternative genetic relationship with alkaline magmas, in which some geochemical and radiogenic isotopic similarities to Bushveld granites are the consequence of broadly contemporaneous development in the same tectonic setting within the same lithosphere, whereas others may be due to hydrothermal overprinting. Similarities with Phalaborwa and also with Bayan Obo, Mongolia, indicate that the Vergenoeg pegmatoid pipe could be an extreme carbonatite-associated member of the Fe-oxide Cu–Au (±REE±P) group of deposits.

Access this article

Log in via an institution

Subscribe and save

• Get 10 units per month
• Download Article/Chapter or eBook
• 1 Unit = 1 Article or 1 Chapter
• Cancel anytime Subscribe now

Buy Now

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Similar content being viewed by others

Author information

Authors and Affiliations

1. Centre for Global Metallogeny, School of Earth and Geographical Sciences, University of Western Australia, Crawley, Australia
   B. H. Goff, R. Weinberg, D. I. Groves & N. M. Vielreicher
2. Vergenoeg Mine, Farm Kromdraai, Rust De Winter, SA, Pienaar’s River, South Africa
   P. J. Fourie

Authors

1. B. H. Goff
   You can also search for this author inPubMed Google Scholar
2. R. Weinberg
   You can also search for this author inPubMed Google Scholar
3. D. I. Groves
   You can also search for this author inPubMed Google Scholar
4. N. M. Vielreicher
   You can also search for this author inPubMed Google Scholar
5. P. J. Fourie
   You can also search for this author inPubMed Google Scholar

Electronic supplementary material

Rights and permissions

About this article

Cite this article

Goff, B., Weinberg, R., Groves, D. et al. The giant Vergenoeg fluorite deposit in a magnetite–fluorite–fayalite REE pipe: a hydrothermally-altered carbonatite-related pegmatoid?.Mineralogy and Petrology 80, 173–199 (2004). https://doi.org/10.1007/s00710-003-0012-6

Download citation

• Received: 05 February 2003
• Accepted: 22 July 2003
• Issue Date: March 2004
• DOI: https://doi.org/10.1007/s00710-003-0012-6

Keywords