NEODYMIUM ISOTOPIC CONSTRAINTS ON THE PROTOLITH AGES OF ROCKS INVOLVED IN PAN-AFRICAN TECTONISM IN THE MOZAMBIQUE BELT OF TANZANIA

Nd isotopic data from samples collected across the Tanzanian sector of the Mozambique belt indicate that the bulk of the belt consists of ea rly Proterozoic crust which was tectonothermally reworked during Pan-A frican time. The only evidence for younger crust is preserved in granu lite complexes that are surrounded by older amphibolite-facies gneisse s. The uniformity of crustal formation ages of the gneisses across mos t of the belt indicates that models explaining the Mozambique belt as a tectonic collage of terranes with different pre-Pan-African crustal histories are invalid.