Origin and Evolution of Precambrian High-Grade Gneiss Terranes, with Special Emphasis on the Limpopo Complex of Southern Africa

A review of Sm-Nd and Lu-Hf isotope studies in the Limpopo Complex and adjoining cratonic areas, and their bearing on models of crustal evolution and tectonism
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Published:February 01, 2011
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Jan D. Kramers, Armin Zeh, 2011. "A review of Sm-Nd and Lu-Hf isotope studies in the Limpopo Complex and adjoining cratonic areas, and their bearing on models of crustal evolution and tectonism", Origin and Evolution of Precambrian High-Grade Gneiss Terranes, with Special Emphasis on the Limpopo Complex of Southern Africa, Dirk D. van Reenen, Jan D. Kramers, Stephen McCourt, Leonid L. Perchuk
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Published whole-rock Sm-Nd and zircon Lu-Hf data from the Limpopo Complex and adjoining areas of the Zimbabwe and Kaapvaal Cratons provide insight into the regional crustal evolution and tectonic processes that shaped the complex.
The Northern Marginal Zone of the complex, and the Francistown area of the Zimbabwe craton, represent an accretionary margin (active at 2.6–2.7 Ga) at the southern edge of that craton, at deep and shallow crustal levels, respectively. The Southern Marginal Zone represents a deep crustal level of the northern Kaapvaal Craton and was not an accretionary margin at the time of high-grade metamorphism (2.72–2.65 Ga). The syntectonic Matok granite was produced by crustal anatexis.
In the Central Zone, the presence of ca. 3.5–3.3 Ga crust is indicated throughout its E-W extent by TNd,DM model ages of metapelites and by zircon xenocrysts and their THf,DM model ages. The ca. 2.65 Ga granitoids in the Central Zone (the Singelele-type quartzofeldspathic gneisses in the Musina area, granitoids in the Phikwe Complex, Botswana, the so-called gray gneisses, and the Bulai charnockite) were formed by anatexis of such old crust, whereas 2.6 Ga juvenile (arc-related?) magmatism produced the Bulai enderbite, and may be a component in the Zanzibar gneiss. The Mahalapye granitoid complex in Botswana was formed by crustal anatexis at 2.0 Ga, but mafic and hybrid rocks of this age have a mantle-derived component.
The data do not prohibit a collisional model for the Neoarchean high-grade metamorphic event in the Central Zone and Southern Marginal Zone of the Limpopo Complex.
- absolute age
- Africa
- anatexis
- Archean
- Botswana
- charnockite
- dates
- diorites
- enderbite
- gneisses
- granites
- high-grade metamorphism
- igneous rocks
- intrusions
- Kaapvaal Craton
- Limpopo Belt
- Lu/Hf
- magmatism
- metamorphic rocks
- metamorphism
- metapelite
- metasedimentary rocks
- Neoarchean
- nesosilicates
- orthosilicates
- plutonic rocks
- Precambrian
- silicates
- Sm/Nd
- Southern Africa
- syntectonic processes
- tectonics
- tonalite
- whole rock
- Zimbabwe Craton
- zircon
- zircon group
- Bulai Pluton
- Singelele Gneiss
- Zanzibar Gneiss
- Matok Pluton
- Phikwe Complex
- Mahalapye Complex
- Sand River Gniess
- Musina Suite