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RESEARCH PRODUCT

Kibaran magmatism and Pan-African granulite metamorphism in northern Mozambique: single zircon ages and regional implications

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Abstract Single zircons from granitoid orthogneisses in the foreland of the Lurio Belt of northern' Mozambique were dated by the evaporation method and yielded 207 Pb/ 206 Pb magmatic emplacement ages between 1040.1 ±0.4 and 1148.2±0.4 Ma. These data confirm previous RbSr whole rock and SHRIMP zircon analyses and record a period of magmatic activity corresponding to the Kibaran event of east central Africa. A1300 Ma old zircon xenocryst in one sample suggests the presence of still older crust in the region. Metamorphic zircons from a granulite-facies psammopelitic gneiss of the Mugeba klippe, which is derived tectonically from the Lurio Belt, were dated by evaporation, conventional techniques and SHRIMP at ∼615 Ma. This us interpreted as reflecting the peak of high-grade metamorphism in this rock and, by implication, in the Lurio Belt. It is concluded from this that the main metamorphism in the basement of northern Mozambique occured in Pan-African times, as is the case in adjacent regions of Tanzania and Malawi, and that this may be the result of collision between East and West Gondwana