Abstract

The Late Proterozoic Mozambique Belt in East Africa is reviewed, using new geochemical and other data. This review leads to the following tectonic interpretation.

A first collision, between 750 and 800 Ma ago, after the obduction of the Baragoi and associated ophiolites of north-central Kenya, produced intense regional recumbent fabrics and structures, a trans-Mozambique Belt stretching lineation, crustal thickening and metamorphism reaching granulite-facies in the lower crust.

Uplift and erosion were followed by closure of a second oceanic area, obduction of the West Pokot ophiolite and collision along the West Pokot suture, possibly about 580 Ma ago. This second collision produced strong within-plate deformation (Baragoian-Barsaloian) especially in N-S dextral shear zones over 100 km east of the West Pokot suture. The shear zones are associated with late Barsaloian within-plate granites.

It is inferred that eastward subduction led to the successive accretion of plates to an eastern foreland, perhaps represented by Malagasy, culminating in the collision of east and west Gondwana.