A GEOTRAVERSE THROUGH THE NORTHERN COASTAL BRANCH OF THE DAMARAN OROGEN WEST OF SESFONTEIN, NAMIBIA

The Pan-African Damaran orogen of Namibia is subdivided into an ENE tr ending inland branch and a NS trending coastal branch. In the northern coastal branch, Damaran metasediments and metavolcanics are exposed t ogether with pre-Damaran basement. The pre-Damaran consists of paragne isses, granitic augengneisses, migmatic gneisses, metagranodiorites an d amphibolites. The Damaran Supergroup starts with the Nosib Group con glomerates and meta-arenites, followed by the Swakop Group, which is s ubdivided into the Ugab Subgroup (siliciclastics, marbles and amphibol ites) and the Khomas Subgroup including the Chuos Formation (glaciogen ic diamictites and banded iron formations), the Karibib Formation (mar bles), and the Kuiseb Formation (siliciclastics and amphibolites). D-1 is the oldest of three deformation phases and developed a bedding-par allel foliation and isoclinal folds. D-2 was the main deformation phas e where thrusting (top-to-east) was accompanied by the formation of N- S trending, east-verging isoclinal folds and E-W stretching lineations . Additionally, there is evidence for concurrent NNW-SSE left-lateral displacement, suggesting transpressive kinematics during D-2. D-3 repr esents a final deformation phase and is the least intense. Pre-Damaran metamorphism attained P-T conditions of the upper amphibolite to gran ulite fades with widespread formation of migmatites. In contrast, the grade of the Damaran metamorphism (synkinematical with D-2) is much mo re variable and shows a marked increase from greenschist fades in the east to granulite facies in the west.