ON THE POSSIBLE OCCURRENCE OF KOMATIITES IN THE ARCHAEAN HIGH-GRADE POLYMETAMORPHIC CENTRAL ZONE OF THE LIMPOPO BELT, SOUTH AFRICA

Abstract

Research Article| June 01, 2013 ON THE POSSIBLE OCCURRENCE OF KOMATIITES IN THE ARCHAEAN HIGH-GRADE POLYMETAMORPHIC CENTRAL ZONE OF THE LIMPOPO BELT, SOUTH AFRICA H. MOURI; H. MOURI Department of Geology, University of Johannesburg, South Africa, e-mail: hmouri@uj.ac.za Search for other works by this author on: GSW Google Scholar W.D. MAIER; W.D. MAIER Department of Geology, University of Oulu, Finland, e-mail: wolfgang.maier@oulu.fi Search for other works by this author on: GSW Google Scholar G. BRANDL G. BRANDL Council for Geoscience, Limpopo Unit, P.O. Box 620, Polokwana, 0700, South Africa, e-mail: gbrandl@geoscience.org.za Search for other works by this author on: GSW Google Scholar South African Journal of Geology (2013) 116 (1): 55–66. https://doi.org/10.2113/gssajg.116.1.55 Article history first online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation H. MOURI, W.D. MAIER, G. BRANDL; ON THE POSSIBLE OCCURRENCE OF KOMATIITES IN THE ARCHAEAN HIGH-GRADE POLYMETAMORPHIC CENTRAL ZONE OF THE LIMPOPO BELT, SOUTH AFRICA. South African Journal of Geology 2013;; 116 (1): 55–66. doi: https://doi.org/10.2113/gssajg.116.1.55 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietySouth African Journal of Geology Search Advanced Search Abstract Komatiites occur in many Archaean and Proterozoic greenstone belts metamorphosed to greenschist or upper amphibolite facies conditions. However, komatiites have so far not been reported from high-grade metamorphic environments (upper granulite facies conditions). Here we report the occurrence of Mg-, Cr-and Ni-rich ultramafic rocks (26 to 31% MgO, 2800 to 3800 ppm Cr, 1400 to 1800 ppm Ni) with unfractionated PGE patterns (8.15 to 12.36 ppb Pt, 6.17 to 13.49 ppb Pd, Pd/Ir ~2 to 6) in the high-grade polymetamorphic Central Zone of the Limpopo Belt, South Africa. The composition of the rocks overlaps with that of Al-undepleted (Munro-type) komatiites from elsewhere, except that the Central Zone samples are markedly enriched in highly incompatible trace elements and show negative Nb anomalies. Based on these data, we interpret the rocks to represent contaminated komatiites of Archaean age – the first such manifestation in the Limpopo Belt and in a high to ultra-high grade (≥900°C, 10 kbar) metamorphic environment. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.