The significance of 3000 Ma granulite-facies mafic dikes in the central zone of the Limpopo belt, southern Africa

1990 ◽  
Vol 48 (3) ◽  
pp. 299-308 ◽  
Author(s):  
J.M. Barton ◽  
D.D. van Reenen ◽  
C. Roering
Keyword(s):  
Southern Africa ◽  
Central Zone ◽  
Granulite Facies ◽  
Limpopo Belt

Sm-Nd isotopic study of garnets and their metamorphic host rocks

1980 ◽  
Vol 71 (2) ◽  
pp. 97-102 ◽  
Author(s):  
O. van Breemen ◽  
C. J. Hawkesworth
Keyword(s):  
Southern Africa ◽  
Granulite Facies ◽  
Distribution Coefficients ◽  
Igneous Rocks ◽  
Isotopic Study ◽  
Tectonic Event ◽  
Basic Magmatism ◽  
Host Rocks ◽  
Selection Of ◽  
Limpopo Belt

ABSTRACTIn this feasibility study, Sm/Nd and 143Nd/144Nd ratios have been determined on garnets and coexisting mineral and whole-rock phases from a selection of amphibolite facies rocks, granulite facies rocks and an eclogite. In two micaceous schists and an eclogite the distribution coefficient of the Sm/Nd ratio in garnet relative to other phases is in the range 2-3, i.e. comparable to values for phenocrysts in igneous rocks. In two granulite facies rocks the garnets have Sm/Nd distribution coefficients relative to other phases in the range 13-20 and have yielded precise ages.Garnet from a granulite facies shear zone from the Limpopo belt in southern Africa, of Archaean age, has yielded concordant duplicate ages of 1974±14 Ma and 1988±14 Ma. These results have been interpreted as relating to the last tectonic event in the region, long after the main gneiss-forming event. Garnet from a granulite facies xenolith from a Carboniferous vent in the Midland Valley of Scotland has yielded an age of 356±10 Ma; this is related to the onset of basic magmatism in the region.

SHRIMP U–Pb zircon geochronology of gneisses from the Gweta borehole, northeast Botswana: implications for the Palaeoproterozoic Magondi Belt in southern Africa

2001 ◽  
Vol 138 (3) ◽  
pp. 299-308 ◽  
Author(s):  
R. B. M. MAPEO ◽  
R. A. ARMSTRONG ◽  
A. B. KAMPUNZU
Keyword(s):  
Central Zone ◽  
Granulite Facies ◽  
Eastern Africa ◽  
High Grade ◽  
Zircon Geochronology ◽  
Granulite Facies Metamorphism ◽  
Grade Metamorphism ◽  
Facies Metamorphism ◽  
High Grade Metamorphism ◽  
Limpopo Belt

This paper presents new U–Pb zircon analyses from garnet–sillimanite paragneisses from the Gweta borehole in northeast Botswana. Concordant to near-concordant analyses of zircon from these rocks reveal a billion year history from 3015 ± 21 Ma for the oldest detrital grain measured, to the age of high-grade metamorphism, 2027 ± 8 Ma. The maximum age of sedimentation in the Magondi belt is constrained by the age of the youngest concordant detrital zircon at 2125 ± 6 Ma. This contrasts with the age of sedimentation in the Central Zone of the Limpopo belt which is Archaean. The comparison of our results with U–Pb zircon data from the Magondi belt in Zimbabwe suggests that the granulite-facies metamorphism in this belt extended between c. 2027–1960 Ma. Granulite-facies rocks with U–Pb zircon ages in this interval are also known in the Ubendian belt and lend support to the correlation of these two segments of Palaeoproterozoic belts in southern and central–eastern Africa. The granulite facies metamorphism in the Magondi belt is coeval with the high-grade metamorphism and granitoids documented further south in the Central Zone of the Limpopo Belt.

The Granulite-Facies Rocks of the Limpopo Belt, Southern Africa

1990 ◽  
pp. 257-289 ◽  
Author(s):  
D. D. Reenen ◽  
C. Roering ◽  
G. Brandl ◽  
C. A. Smit ◽  
J. M. Barton
Keyword(s):  
Southern Africa ◽  
Granulite Facies ◽  
Limpopo Belt

A Discussion on the evolution of the Precambrian crust - The Limpopo mobile belt — Southern Africa

1973 ◽  
Vol 273 (1235) ◽  
pp. 463-485 ◽  
Keyword(s):  
Shear Deformation ◽  
Southern Africa ◽  
Central Zone ◽  
Kaapvaal Craton ◽  
Mobile Belt ◽  
High Grade ◽  
The South ◽  
Geological Time ◽  
The North ◽  
Limpopo Belt

The Limpopo belt is an extensive ENE-trending linear zone of high-grade metamorphic tectonites which separates the Archaean nucleii of the Rhodesian craton to the north from the Kaapvaal craton to the south. The belt consists of reworked Archaean granite-greenstone terrain with an early Proterozoic cover sequence, the Messina Formation, infolded and metamorphosed with the basement. Two major zones of shearing and transcurrent dislocation separate marginal granulite zones from a central zone which consists of complexly infolded cover rocks and reworked basement. The northern granulite zone appears to grade transitionally into the Rhodesian craton to the north, whereas there is some evidence that the southern granulite zone is faulted against the Kaapvaal craton to the south. The whole belt has behaved as a zone of crustal weakness throughout geological time, and is characterized by repeated shear deformation, igneous intrusion and extrusion, despite the cessation of major regional tectono-thermal reactivation about 1900 Ma ago.

Petrological evolution in the roof of the high-grade metamorphic Central Zone of the Limpopo Belt, South Africa

2005 ◽  
Vol 142 (3) ◽  
pp. 229-240 ◽  
Author(s):  
ARMIN ZEH ◽  
REINER KLEMD ◽  
JAY M. BARTON
Keyword(s):  
South Africa ◽  
Temperature Increase ◽  
Central Zone ◽  
Granulite Facies ◽  
High Grade ◽  
Metamorphic Overprint ◽  
Granulite Facies Metamorphism ◽  
Facies Metamorphism ◽  
Zonation Patterns ◽  
Limpopo Belt

In this study we present new petrological results from the Endora Klippe in the Central Zone of the Limpopo Belt, which may result from horizontal tectonics during the Proterozoic at c. 2.0Ga. Microstructures, assemblages and garnet zonation patterns observed in metapelitic rocks provide evidence that the Endora Klippe rocks underwent a contemporaneous pressure–temperature increase from c. 600°C/5kbar to 650°C/6.5kbar. This is inferred by the use of conventional geothermobarometry and interpretations based on quantitative phase diagrams in the system MnO–(TiO2)–(CaO)–(Na2O)–K2O–MgO–Al2O3–SiO2–H2O. Thus, the petrological results indicate that this part of the Central Zone only underwent a medium-grade metamorphic overprint during a single orogenic event and was never affected by granulite-facies metamorphism, as reported from other parts of the Limpopo Belt. The inferred P–T path, in combination with previous structural and petrological results, leads to the conclusion that the area surrounding the Endora Klippe forms the roof zone of the c. 2.0Ga old granulite-facies rocks forming wide parts of the Limpopo Central Zone.

Two orogenic events separated by 2.6Ga mafic dykes in the Central Zone, Limpopo Belt, southern Africa

2017 ◽  
Vol 289 ◽  
pp. 129-141 ◽  
Author(s):  
Hangqiang Xie ◽  
Alfred Kröner ◽  
Günther Brandl ◽  
Yusheng Wan
Keyword(s):  
Southern Africa ◽  
Central Zone ◽  
Mafic Dykes ◽  
Orogenic Events ◽  
Limpopo Belt
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