Anorogenic alkaline ring-type complexes of the Damaraland province, Namibia, and their economic potential

Abstract

Abstract provided by author:

In Namibia the Damaraland igneous province is of Mesozoic age and it contains 15 alkaline ring-type complexes. These complexes are situated along north-eastern trends which correspond to transform directions of the South Atlantic. During the opening of the South Atlantic (Gondwana breakup) Pan-African age lineaments were reactivated which allowed emplacement of anorogenic alkaline magmatism. A zonation of alkaline granite and syenite-type in the west and carbonatite and undersaturated-type ring-complexes in the east correlates with down- and upwarp axes parallel to the line of Gondwana fragmentation

Alkali- and H+-metasomatism is related to the alkaline and syenite-type whereas alkali metasomatism (fenitization) is associated with carbonatite and undersaturated-type ring-complexes

Sn, W and Ta mineralization is associated with alkaline granites of some of the alkaline granite and syenite-type ring-complexes. Fe, F, P04, Nb, Th, REE, Sr, Zn and Pb mineralization is associated with carbonatite complexes

Potential exists for: (i) porphyry Cu-Mo and epithermal-type (Au, Ag, Pt-metals, base metals) mineralization in the alkaline granite and syenite-type ring-complexes and (ii) disseminated Cu, Au, Ag and Pt-metals in carbonatite and undersaturated-type ring-complexes