A magmatic age and four successive metamorphic events recorded in zircons from a single meta-anorthosite sample in the central zone of the Limpopo Belt, South Africa

• Published in: Journal of the Geological Society Vol. 166; no. 5; pp. 827 - 830
• Main Authors: Mouri, H, Whitehouse, M. J, Brandl, G, Rajesh, H. M
• Format: Journal Article
• Language: English
• Published: London, UK Geological Society of London 01.09.2009; The Geological Society of London; Geological Society; Geological Society Publishing House
• Subjects: absolute age; Africa; age; Archean; cathodoluminescence; Crystalline rocks; dates; Earth sciences; Earth, ocean, space; Exact sciences and technology; Geochronology; Geological time; Geology; high-grade metamorphism; igneous and metamorphic rocks; Igneous and metamorphic rocks petrology, volcanic processes, magmas; ion probe data; isotope ratios; Isotopes; lead; Limpopo Belt; Magma; magmatism; mass spectra; meta-anorthosite; metaigneous rocks; metals; Metamorphic rocks; metamorphism; Neoarchean; nesosilicates; orthosilicates; overgrowths; Pb-207/Pb-206; Petrology; Precambrian; protoliths; silicates; South Africa; Southern Africa; spectra; stable isotopes; U/Th/Pb; zircon; zircon group; South Africa; Limpopo Belt; Southern Africa; Africa; cathodoluminescence; nesosilicates; metaigneous rocks; U/Th/Pb; protoliths; metamorphic rocks; metaplutonic rocks; drill cores; zircon; silicates; ions; meta-anorthosite; overgrowths
• ISSN: 0016-7649; 2041-479X
• DOI: 10.1144/0016-76492008-148

Ion microprobe U-Th-Pb analyses combined with cathodoluminescence imaging of zircons from a meta-anorthosite from the Central Zone of the Limpopo Belt record five distinct events. The most concordant ages of cores of zircon yielded a weighted mean 207Pb/206Pb age of 3344±3.6 Ma, representing the protolith age. The unzoned overgrowths yielded four discrete groups with weighted mean 207Pb/206Pb ages of 3150±15 Ma, 2614±4 Ma, 2488±22 Ma and 2009±28 Ma, representing four possible metamorphic events in the Central Zone. This is the first time that a succession of several metamorphic events has been demonstrated in a single rock-type from the Limpopo Belt.