The structural geology of Mgeta Meta - Anorthosite and its Titano-Magnetite bodies

The Mgeta Meta-anarthosite situated in the western part of the Uluguru Mts. occurs as a large independent massive intrusion in the surrounding Banded Pyroxene Granulate. It is part of the Late Proterazoic Mozambique mobile belt; which on average composition is of Iabradorite Type Mete-anorthosite originating from gabbroic magma. Attempts to subdivide this massive complex onto map able types based on mafic mineral content have succeeded. Although distinct types of meta-anarthosite can be discerned locally, their distribution is heterogeneous within the limits of the 25 sq. km. mapped area. The textural evolution of the plagioclases is essentially a result of metamorphism, deformation and recrystallization of the initial magmatic rock to a reworked metamorphic rock. Grain boundary sliding is the major deformation mechanism within the plagioclases. The contact between the mete-anorthosite and the banded pyroxene granulite is a thrust plane. The predominant foliation S2 is folded and the observed multi domical surfaces are due to inhomogeneous deformation in heterogeneous stress field. Lineation is synchronous with or later than S2 in which it mostly lies.