Rodinia and earlier: 2,650–900 million years ago
Although the formation of Earth began over 4.5 billion years ago, events in Namibia are only traceable for the most recent half of this time. What is known of Namibian geological history begins with material and evidence from about 2,650 million years ago. This is the beginning of the first and longest of the four periods, but the one about which the least is known. It starts with the oldest rocks found in Namibia and continues with the formation of the supercontinent Rodinia about 1,200 million years ago and then its break-up about 900 million years ago.
2.17 Namibia's basement geology, 2,650–900 million years ago
The oldest rocks are a mixture of both metamorphosed igneous and sedimentary rocks from about 2,650 million years ago. They belong to the Epupa Metamorphic Complex, which extends from the Hoanib River west of Sesfontein to the Kunene River. The complex may be more extensive, but hidden underground, since geophysical studies have shown that similar rocks occur below the surface in the vicinity of Tsumeb, Grünau, and the Cuvelai in northern Namibia.
The Abbabis Metamorphic Complex formed about 2,160 million years ago. It lies between the Kuiseb River and Okahandja in the base of folds of the Damara Orogen, a folded mountain belt, which emerged much later around 550 million years ago. The Huab Metamorphic Complex formed about 1,930 million years ago and now forms the Kamanjab Inlier north of Khorixas. Smaller outcrops of this complex have also been identified south of Otjovasando and southeast of Outjo.
Earth, 1,500 million years ago17
The Congo and Kalahari cratons that underlie Namibia today were separate at this time. As far as geologists can tell, their edges cut through Namibia from the central coast to the northeast. Likewise, Angola, Botswana, Malawi, Tanzania, Zambia and Zimbabwe were probably also divided between these two early continents. This reconstruction depicts Earth before the formation of Rodinia, which took place between 1,200 and 1,000 million years ago.
Photo: J Indonga
This is banded gneiss of the Namaqua Metamorphic Complex near the Tantalite Valley, some 30 kilometres south of Warmbad. The parent rocks of the Namaqua Metamorphic Complex are approximately 1,930 million years old, but the complex itself was formed around 1,200–1,000 million years ago when the Kalahari, Congo and Rio de la Plata cratons collided to form the supercontinent Rodinia. It is thought that the collision created the 1,400-kilometre-long and 400-kilometre-wide belt of the Namaqua Metamorphic Complex, which stretches from the Lüderitz area across the Orange River to KwaZulu-Natal in eastern South Africa.