A part of the Ubendian Orogenic Belt in northern Malawi and Zambia |
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| Authors: | W R Fitches Ph D B Sc |
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| Institution: | 1. Department of Geology, University of Ghana, Legon, Accra, Ghana, W Africa
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| Abstract: | The Ubendian Orogenic Belt of southern Tanzania continues across the strike into northern Malawi where it is represented by the Misuku Belt. The Misuku Belt has been examined in two areas on the international boundary between northern Malawi and Zambia; the Mafingi Hills area and the western escarpment of the Nyika Plateau. In each area the Misuku Belt has been divided into three distinctive rock units: 1. the Misuku Gneisses which were metamorphosed in the epidote amphibolite to amphibolite facies, 2. the Jembia River Granulites, metamorphosed under conditions near to the triple point between the cordierite-granulite, granulite and amphibolite facies and 3. the post-tectonic Nthonga and Nyika Granites of the Mafingi Hills and Nyika Plateau respectively. Evidence is provided to show that the two metamorphic units are stratigraphic equivalents which were deformed and metamorphosed in different environments and subsequently placed in juxtaposition. The results of radiometric age determination made on the Misuku Belt provide no evidence of the true age of the granites nor of the time of metamorphism. The apparent ages are considered the result of overprinting during a later tectono-thermal event. |
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