Skip to Main content Skip to Navigation
Theses

Effets de la contamination continentale et des interactions fluides-roches sur le Platreef, Complexe Igné du Bushveld, Afrique du Sud.

Abstract : The Platreef is a PGE-bearing horizon found at the base of the northern limb of the Bushveld complex, South Africa. Samples from elsewhere in the northern limb and the Bushveld in general were analysed in order to compare the characteristics of this marginal unit with typical Bushveld cumulates. Most samples from elsewhere in the Bushveld are not altered and present relatively homogenous δ18O values which are significantly higher than mantle-derived basalt magmas. These indicate extensive crustal contamination before intrusion of the magmas. The Platreef, sampled at 4 sites, shows extensive visible evidence for alteration and both stable and radiogenic isotopes indicate additional crustal contamination. Calcsilicate xenoliths are ubiquitous and contamination by partial melts of the granitic wall-rock was also observed. The most altered cumulates appear to be in contact with the most fractured country rocks. Circulation of fluids was via channels and both magmatic fluids and fluid expelled from the sedimentary country rocks are implicated. As these fluids contained chlorine and CO2, they could have influenced the original precipitation of PGE's and their subsequent redistribution during alteration.
Document type :
Theses
Complete list of metadata

https://tel.archives-ouvertes.fr/tel-00077226
Contributor : Julie Pronost <>
Submitted on : Monday, May 29, 2006 - 7:52:18 PM
Last modification on : Tuesday, April 20, 2021 - 12:10:52 PM
Long-term archiving on: : Monday, April 5, 2010 - 9:46:36 PM

Identifiers

  • HAL Id : tel-00077226, version 1

Citation

Julie Pronost. Effets de la contamination continentale et des interactions fluides-roches sur le Platreef, Complexe Igné du Bushveld, Afrique du Sud.. Géochimie. Université Blaise Pascal - Clermont-Ferrand II, 2005. Français. ⟨tel-00077226⟩

Share

Metrics

Record views

386

Files downloads

1589