The mafic Audawib Suite in the Central Damara orogen of Namibia: geochemical evidence for volcanic arc volcanism
Abstract The Damaran metagabbro-norites and metagabbros (now hornblendite) of the mafic Audawib Suite occur as unfoliated xenoliths in the well foliated, syn-D 1 -intruded, dioritic Okongava Batholith. Geochemically the rocks classify as low-K tholeiitic gabbroids likely to have formed in a volcanic arc setting overlying a subduction zone. The magma fractionated (approximately 30 per cent melt) from depleted mantle which was wedged between the over riding Congo Craton and the subducted ocean crust of the Kalahari Plate. The cumultic and porphyritic Audawib Suite represents crystallisation in a magma chamber/s at depth. Here magmatic differentiation and solidification was completed before the andesitic Okongava magma intruded into the Andean-type continental margin which existed during the Pan-African times.