Geological background

Our Earth is estimated to be around 4½ billion years old and the geological history of Namibia covers more than 2 billion years. At this time the face of the earth looked completely different. Huge oceans covered most of the planet, the land in between being called cratons. Life on Earth was limited to a variety of bacteria and algae which were able to survive in this inhospitable environment with very little oxygen and much carbon dioxide.

The area that is now southern Africa consisted of two main islands; the Kalahari Craton in the South East, and the Congo Craton in the North. These were part of the lands that would later form the whole African continent. Over millions of years this area grew through the creation of mountains, exposing greater land mass above the ocean. The first mountains were created in Nambia between 2.1 and 1.6 billion years ago during the Vaalian age (Epupa Metamorphic Complex, Huab Formation, Grootfontein Formation) and Lower Mokolian age (Rehoboth and Sinclair Sequences). The Upper Mokolian age saw the creation of the second wave of mountains, between 1.6 and 1 billion years ago. Today, the ground we walk on in the South of Namibia was formed at this time, and is called Namaqua Metamorphic Complex. The third period of mountain creation occurred about 800 million years ago when the Congo Craton collided with the Kalahari Craton. The area between the two cratons had formerly been a shallow ocean where thick carbonate deposits had solidified into limestone. After the collision, the limestone was transformed into marble by the high temperatures and pressure, and became the huge Damara mountains. 

Marble near Karibib

This marble is nowadays processed in the Marbleworks at Karibib. The global plate movements of around 560 million years ago pushed many areas together to form the supercontinent Gondwana (originally Gondwanaland), which included most of the landmasses which make up today’s continents of the Southern Hemisphere, including Antarctica, South America, Africa, Madagascar, India, Arabia, Australia, New Guinea and New Zealand.

KaokolandDuring the millions of years that followed the only changes to the shape of the Damara mountains came from weather erosion and subsidence. The fourth period of mountain creation in Namibia began around 300 million years ago, named the Karoo time, which dramatically changed the face of Namibia. At that time Namibia was closer to the Antarctic and much of the interior was covered with glaciers. After further plate movement 280 million years ago, Godwana moved closer to the equator, and the ice began to melt, leaving behind huge amounts of broken down rock. These formations can still be seen in some parts of Namibia, especially in the area of Kaokoland (the Dwyka Formation).

Over time, rocks fell down into lakes and rivers and were naturally transported to widespread deltas. One of these is the Omingonde Formation in Central Namibia. Subsequent climate changes created dry, hot sand deserts, and the Etjo Sandstone Formation that you can still see today.

Skeleton Coast130 million years ago, plate movements completely changed the face of the Earth. What began with long fissures in the ground (many kilometres long), ended with the final breaking-up of the area of Godwana, leading to the formation of the continents as we know them. This was the time when the Namibian Coast was created. Basalt lava came up through the large cracks in the land and flooded huge areas on the surface.

These areas are today known as the Etendeka Formation in the Northern Damaralands and are very scenic. During this period the edges of Southern Africa were lifted up and this is how the Kalahari Basin was formed. With this event the Karoo time ended. About 65 million years ago the fifth period in the geological development of Namibia took place. The most significant change in this period was that the mountains of the Karoo time became severely eroded, exposing the lower rock layers of the Precambrian era.

Tsondabvlei(The Precambrian is an informal name for the supereon comprising the eons of the geologic timescale that came before the current Phanerozoic eon. It spans from the formation of Earth around 4500 Ma (million years ago) to the evolution of abundant macroscopic hard-shelled animals). The Tsondab Sandstone Formation is an example of where these rocks have come down from the mountains to form new landscape below (30 million years ago). 10-20 million years ago Namibia had a much higher humidity, with many more rivers than today. However over the last 5 million years the climate has been stable, and it was during this recent time that the Namib Desert was formed. The creation of the sand dunes began around 2 million years ago, and they are still evolving today. In other parts of the world, at this time, there was much ice and a freezing climate, which caused a global drop in the level of oceans.

Khomas Highlands

The name Khomas comes from the Nama word ‘L Omas’ which means Mountains. The Khomas Highlands were created around 650 million years ago. The Khomas subgroup is the youngest of the Damara Sequence and consist of metamorphic rocks like mica schist, traversed by micaceous quartzite, subordinate calcareous schist and impure marble, and amphibole schist. The schists form a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as mica, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is produced. By definition, schist contains more than 50% platy and elongated minerals, often finely interleaved with quartz and feldspar.

Windhoek Green Belt Landscape

Mica schist

Rose quartzWithin the landscape, the rock formations are mostly composed of mica-rich and quartz-rich schist that has many fractured quartz veins. The southern area is mainly characterised by Biotite schist with quartzite, the metamorphic product of siliceous rock such as sandstone. It consists of recrystallised interlocking quartz crystals, which forms the Windhoek aquifer that has been utilised as a source of relatively clean water. These rock formations are in the category of the Kuiseb formation of the Damara Sequence, with many summit heights reflecting older land surfaces of Khomas Hochland dating back 700 million years. There are abundant faults in the north-western area, with some of the rivers and streams following the fault lines.

Relevant literature

  • Geology of Dusternbrook and the Khomas Hochland

    Geology of Dusternbrook and the Khomas Hochland.

    In German and in English
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