The Naukluft Mountains are located in central Namibia and are part of the larger Naukluft Plateau. The geology here is characterized by a sequence of sedimentary rocks that were deposited during the Proterozoic era, between 2.5 billion and 541 million years ago. The dominant rock types in the area are quartzite, shale, and sandstone, which were deposited in shallow marine environments. Our area is characterised by a dolomite nappe complex associated with the Damara Orogen. Massive travertines formed by resurgences on the disconformity between phyllites and slates of the Remhoogte Formation and the overlying dolomites of the Noab Formation.
Our farm, located in the Naukluft Mountains, is characterized by its rugged topography and steep slopes. The soil in the area is predominantly shallow and rocky, with limited organic matter and nutrients. The dominant soil type in the region is lithosol, which is a thin layer of soil that has formed on top of rocks and other geological materials. Soils consist of alluvium, sand, gravel, and calcrete on the valley floor (pre-Damara basement).
The highest point of Nauklouft occurs on Arbeid Adelt, on the northwestern side, at 1960m. The valley floor is underlain by Cenozoic surficial deposits of sand and calcrete. Mountain flanks of the valley consist of green shale of the Pavian Nappe at the bottom, overlain by gray dolomite of the Kudu Nappe of the Naukluft Complex. The basement conists of meta-sedimentary and meta-volcanic rocks, gneisses and granties, varying in age btw. 1900 and 1000 Ma. The basement is overlain by sediments of the Kuibis and lower Schwarzrand Subgroups of the Nama Group. The top of this unit is truncated and overlain by four intensely folded and imbricated allochthonous nappes (the Dassie Nappe (dolomite, shale, limestone), Pavian Nappe (shale, conglomerate and dolomite), Kudud Nappe (dolomite, limestone, shale, conglomerate), and the Zebra Nappe (quartzite, black limestone, conglomerate, shale and dolomite), containing several lithologically distinct sequences of Neoproterozoic age. This unit of nappes is separated from a single lower nappe by a thin dolomite band, the Sole Dolomite. The Naukluft nappes, forming the top part of the mountains, are very large, sheet-like bodies, which were emplaced along low-angle thrusts, with movement towards the S and SE. They compare lithologically to the Swakop Group of the Damara Sequence and originated in the Hakos Mountains to the North, 78km away. The movement occurred 500-550 Ma ago and is related to the Damaran Orogeny.
Younger dissolution of dolomites and limestones in the Naukluft Complex has given rise to karstification of the plateau with a resulting extensive underground drainage system. The soft, semi-friable, porous limestone is formed by evaporation of the calcium carbonate-rich water. The contact between the Pavian and Kudu nappes is seen at the Blässkopf tufa, which is 103 m high. Here the accumulation of travertine, deposited by springs, developed along the contact. These form when meteoric waters percolating through the dolomite encounter the impermeable shale. The waters carry carbonates dissolved from the dolomite, which is re-deposited, forming tufa.
Near Toms tufa, a cascade tufa of five cascades, a number of lithologies are observed. These start with green shale, boulder shale and white dolomite of the Pavian Nappe at the base, followed by grey dolomite of the Kudu Nappe on top. The isolated hills contain the green shale of the Pavian Nappe and dolomite of the Dassie Nappe. As the road turns toward Büllsport (the neighbouring farm) limestone of the Zebra Nappe, overlain by dolomite of the Dassie Nappe form the mountains toward the southwest whilst in the northeast, dolomite of the Dassie Nappe prevails. Intercalated in these limestones and dolomites is a layer of quartzitic shale of the Zebra Nappe, with tufa development.
Sources
- Republic of South Africa. 1980. South West Africa/Namibia Geological Map. 1:1 000 000. Pretoria: Government Printer.
- Schneider, G. 2004. The Roadside Geology of Namibia (Sammlung geologischer Führer 97). Gebrüder Borntraeger: Berlin-Stuttgart.