Polyphase deformation and metamorphism at the Kalahari Craton — Mozambique Belt boundary

Abstract

The rocks of the Kalahari Craton in central western Mozambique have crystallization ages of between c. 2300 and 3400 Ma and comprise dominantly granite-greenstones, peraluminous two-mica granites, subordinate younger mafic and granitic intrusions of uncertain age and cover sedimentary rocks. The rocks of the Mozambique Belt comprise c. 1100 Ma intrusive granitoids as well as mafic intrusives and supracrustal migmatite gneisses of uncertain age. The boundary zone between and including these two crustal provinces is characterized by a strong N-S penetrative planar and migmatitic fabric. Sparse kinematic indicators suggest a sinistral sense of displacement along this shear zone. The metamorphic gradient increases from west to east from low grade on the Kalahari Craton to high-grade in the east, characterized by two generations of anatectic migmatization. 4°Ar/39Ar thermochronology on mica suggests that the Kalahari

Mesoproterozoic intraplate magmatism in the Kalahari Craton: A review

“…1100-1105 Ma, which fall in the same range as Umkondo igneous activity (e.g., Hanson et al, 1988b;Manhica et al, 2001). It is possible that some of this Mesoproterozoic basement may record the influence of the large-scale Umkondo thermal anomaly that affected the craton interior at 1.1 Ga.…”

The Mesoproterozoic Irumide belt of Zambia

“…In our view, the exposed part of the Irumide belt lies outside the main site of closure of a Mesoproterozoic ocean to the southeast. Mesoproterozoic oceanic crust has been documented to the southeast of the Irumide belt in the 1.4 Ga Chewore complex in Zimbabwe (Johnson, 1999), providing evidence of an oceanic realm to the southeast as far back as 1.4 Ga. A series of juvenile magmatic arcs have been recognised in southern Malawi (1.04-1.00 Ga, Krö ner et al, 1999), northwestern Mozambique (1.05-1.01 Ga, Krö ner et al, 1997Manhica et al, 2001), northern Zimbabwe (1.10-1.05 Ga, Johnson and Oliver, 2004) and central Zambia (1.10 Ga, Hanson, 1999;Katongo et al, 2004) and are interpreted to have been accreted to the southern margin of the Bangweulu block during Irumide tectonism.…”

Proterozoic Tectonostratigraphy and Paleogeography of Central Madagascar Derived from Detrital Zircon U‐Pb Age Populations

“…The Tanzania craton/Madagascar Paleoproterozoic passive margin may therefore have persisted as an exterior passive margin with Kibaran accretionary events restricted to the west and south of Madagascar, for example, in present-day Zambia and Mozambique and in the Kibaran belt between the Tanzania and Congo cratons where ∼1-Ga ages are well documented (e.g., Romer and Lehmann 1995;Manhica et al 2001;De Waele et al 2003). Most reconstructions, including the most recent (Torsvik 2003), show Tanzania in an external position on the western edge of Rodinia at 750 Ma, so our model represents only a slight modification in overall Rodinia paleogeography.…”