Namibia is a geologist's paradise
Season 5: Destination Unknown1 August 2021
Namibia is a dream for geologists like me. Here you find volcanic craters that are not volcanic craters, burnt mountains and star shaped dunes. Some of these geological features are beautiful just because of their shape or size, but when you understand exactly what it is that you are looking at, you will realise how mind-blowing they really are. Let me share with you the 8 geological wonders of Namibia that impressed me the most!
1. Diamonds of Namibia
When you enter Namibia from South Africa, you can’t escape the diamonds. All the way from the Orange river and the town of Oranjemund up to Luderitz, about 400 kilometers north, is diamond territory. Worldwide, Namibia is known for its high quality diamonds, and since the first diamonds were discovered, about 80 million carats have been recovered. That is about 6.000 kilograms of diamonds!
Diamonds are not created easily. In order to create a diamond you need temperatures of about 1200 degrees Celsius and pressures of about 50 kilobars. Such conditions are only found at great depth, at least 160 kilometers deep, in the earth’s upper mantle. The only way diamonds can reach the earth's surface is through volcanic pipes. Such narrow pipes are created by gas explosions at depths of 200 kilometers below the earth’s surface. These explosions carry mantle rocks, including diamonds, at high speed to the surface. The pipe rocks are called kimberlites and most of the kimberlite rocks in South Africa for example, are between 90 and 120 million years old.
The diamonds that reach the surface are much, much older, and most diamonds have been dated to be older than 3300 millions years. That means they date back nearly to the beginning of the planet! Knowing that, certainly gives a different appreciation for these shiny gemstones.
TIP: There are still active diamond mines in Namibia. You can’t visit those, but in the ghost town of Kolmanskoppe you can learn more about diamond mining in the early days when they were first discovered.
2. Fish River canyon
The Fish River Canyon is the second largest canyon in the world, after the Grand Canyon in the USA. The canyon is an impressive 27 kilometers wide at its widest point and up to 549 meters deep! The Fish river plunges into the canyon and continues for about 90 kilometers until the end of the gorge at Ai-Ais. That is where I stayed when I visited this natural phenomenon.
The formation of this huge canyon started about 300 million years ago. There are rocks in this area that are even much older: up to 1500 million years old! These rocks are part of the Namaqualand Metamorphic Complex and are some of the oldest rocks found in Namibia.
The canyon formed along something which is called a tectonic graben structure, meaning that a block of the earth’s crust subsided between two fault zones. In the early stages of the formation of this canyon, the river was flowing 300 meters higher than it is today. It could have lowered a lot more, but very hard rock layers prevented the river from going any deeper fast, so the erosion forces of the water went sideways, resulting in a much wider canyon.
When the Gondwana supercontinent, the combined continents of Africa, South America, India, Antarctica and Australia, started to break up around 120 million years ago, the continental edges were lifted up. As a result, the gradient became steeper, the Fish river faster flowing, and the erosional powers larger. Over millions of years, the river finally cut through the hard quartzite rocks of the Nama Group, until it reached the deepest rocks of southern Namibia: the ancient gneisses of the Namaqualand Metamorphic Complex.
Isn’t it impressive that something that started millions of years ago has resulted in this natural beauty?
TIP: You can visit the Fish River canyon along the well graded gravel roads, but for the more adventurous travelers, I recommend taking the other route. You will then ride along the edge of the canyon and most likely have the entire place to yourself.
Looking at a satellite image of the Brukkaros, you might think it is a volcanic crater. Or that is was created by a meteorite hitting the earth! Researchers have thought it was a volcanic crater for a long time. The typical form and slope of the mountain resembles an (extinct) volcano so at that time it seemed to be the most logical conclusion. The only problem was that in the vicinity of the Brukkaros, not a single volcanic rock was found!
Only later, research revealed the true nature of this impressive landmark. It turned out that even though there has been volcanic activity in this area, the magma didn’t break through the earth’s crust like with ‘normal’ volcanoes. The magna stayed under the ground and mixed with shallow groundwater. The groundwater immediately turned into steam and this pressure resulted into a huge explosion. So the crater that we see today was the result of this enormous steam explosion! In geological terms, such a volcanic event is called a phreatomagmatic explosion. So the crater is not truely a crater, but a caldera - a collapsed magma chamber.
TIP: The Brukkaros can be reached via a 55 kilometer gravel road from the town of Tses, north of Keetmanshoop. Brukkaros is not a very popular destination, so expect to have the entire place to yourself! It took me about 1 hour of hiking to get inside the caldera. It’s also possible to hike to the top, from where you supposedly have magnificent views. When I visited the site, there was a strong wind though, that was about a gale force. So in order not to risk to be blown off the top, I didn’t attempt that hike!
4. Giants playground
You can find Giants Playground just outside Keetmanshoop in the southern part of Namibia. According to the local legend, giants have played here with these huge rocks and created hundreds of rock piles. Small to them, impressive to us. A beautiful story, but not how geologists think this area was created.
Giants playground consists of weathered dolerite dykes. Dolerite is a blackish, grey dyke rock which resembles basalt when you first see it. But whereas basalt emerges as lava to the earth’s surface, dolerites are classified as intrusive rocks. The lava they are made of solidified below the earth’s surface.
When the Giants playground was created it was still below the earth’s surface, but groundwater already infiltrated through the horizontal and vertical fissures in the rocks and created the dissection of the dolerite dykes into boulders. Over time, when erosion exposed the boulders to the elements, the boulders were rounded further and further by wind and rain until the way they look today.
The so-called dolerite swarm outside Keetmanshoop covers a surface of 18000 km2 (!) and it originates from about 180 million years ago. This coincides with the initial activity of the splitting of the Gondwana supercontinent, which I mentioned before regarding the Fish River Canyon.
5. Sossusvlei in the Namib Desert
The Namib Desert is a narrow coastal desert, stretching all the way from the South of Angola through Namibia down to the Northern Cape Province of South Africa. It is considered by most to be the oldest desert in the world. Opinions on its exact age vary, but scientists agree that it is at least 35 million years old.
The Namib desert was created through lack of rainfall. The cold Benguela current, that comes from the South Pole, is responsible for cooling off the year-round southwestern oceanic winds. That cold air pushes itself underneath the warm inland air masses, creating an air inversion. Such an air inversion prevents the formation of any turbulence, meaning no rain clouds can be formed. The result of this natural phenomena is an average rainfall of 15 mm per year for the Namib Desert, although some areas haven’t seen rain in the last 20 years.
The only moisture you can find here is the coastal fog, which is also a result of the Benguela current. The atmospheric humidity of the cold oceanic air condenses at the boundary of the warm air masses on the coast and then fog is created.
Riding through fog alongside the coast of Namibia is inevitable and part of experiencing coastal Namibia. On most days the fog will disappear during the morning, but if you are unlucky, it can be grey and foggy for weeks!
What impressed me most about the Namib Desert, besides its vastness, was Sossusvlei. Just south of the Kuiseb river, the Great Sea of Sand begins or ends. It all depends on how you look at it. The area around Sesriem and Sossusvlei is one of the best known places to experience Namibia’s enormous dark red ochre sand dunes. This beautiful red colour is caused by iron oxides that cover the grains of sand in thin coatings. So what you are looking at is basically the rusting of sand!
The Namib desert has many different dunes: transverse dunes, longitudinal dunes, Barchan dunes, and star dunes. Around Sossusvlei you can find star dunes. Star dunes are dunes overlapping each other, forming the shape of a star thanks to the winds of equal strength blowing from different directions.
The dunes stand over 300 meters above the Tsausab river and are amongst the tallest sand dunes in the world.
TIP: Sand storms are not uncommon in this area. When you are caught in one, consider stopping at the scientific research centre at Gobabeb. They will gladly host you and it’s a great opportunity to speak to some of the scientists that conduct all sorts of biological and geological research in the Namib Desert!
The name Brandberg, which translates as ‘Fire Mountain’, was given to this mountain because of the red glow of the granite in the afternoon sun.
The Brandberg is the highest mountain in Namibia and with an average height of 1800 meters above its surroundings, the mountain can be seen from far away. The mountain has a diameter of 20 kilometers and mainly consists of granite. The formation of the Brandberg took place about 130 million years ago, as a rising granite intrusion, solidifying at 2 kilometers below the earth surface. It took millions of years of erosion before the mountain as we see it today, got finally exposed.
The Brandberg also hosts thousands of rock paintings made by the San people. They are estimated to be between 2,000 and 6,000 years old. The most famous of them all is called the ‘White Lady’, which, after more careful research, turned out to be a depiction of a traditional healer, instead of a woman. The paintings are definitely worth a visit.
The area around the Brandberg is known for its quartz crystals. There are several places where locals mine large pieces of amethyst. These crystals were formed in the lava flows from the Goboboseb Mountains, not far from the Brandberg.
TIP: Desert elephants regularly visit the area around the Brandberg, so keep an eye out for footprints and droppings/ Who knows, you might bump into one of these giants!
The ragged peaks of the Big Spitzkoppe are an amazing contrast with the surrounding flat desert and it looks dramatic even from far away. The two Spitzkoppe mountains have a similar origin as the Brandberg, except that they were formed slightly later. The granitic magma of Spitzkoppe intruded about 100 million years ago. Just like the Brandberg, the intrusions solidified several kilometers below the surface and were only exposed to daylight after millions of years of erosion that weathered away the softer rocks in which it intruded.
This process is called Inselberg formation and it’s an example of how chemical weathering works. Because the granite was much more resistant to weathering, it ‘rose’ in height, relative to its surroundings. Both Spitzkoppe mountains are rich in all sorts of crystals, which the locals are selling everywhere in the region in little stalls. These minerals are found in pegmatites. Pegmatites were formed in the late cooling phase of the granite. The more abundant elements such as aluminium and potassium were already solidified into minerals such as the feldspar or mica in granite. Pegmatites, however, contain more rare elements such as beryllium, boron and lithium(!). Silver topaz is another collectors item which can still be found in this region.
TIP: Around Spitzkoppe are lots of little dirt roads that you can ride, and with the two great landmarks of the Small Spitzkoppe and Big Spitzkoppe nearby, you won’t get lost!
8. Burnt Mountain
The Burnt Mountain in Namibia is perhaps the best example of a Namibian geological feature that is only impressive when you understand how it was formed. Many people visit this place and are disappointed because all they see is some purplish rock.
But what you are looking at here is an impressive example of a process called contact metamorphism. A large amount of basaltic magma was pushed up here, right against a layer of shale. Shale is finely stratified sedimentary rock that was formed from consolidated mud or clay. This material can be split easily into fragile slabs. The touch of those molten rocks of over 1000 degrees Celsius immediately caused thermal and chemical changes to the shale. Because the shale was a former lake deposit, it is very rich in organic matter which vaporized when it got in contact with the basaltic magma. It was as if these shale rocks were suddenly cooked in a very hot oven! There were even thin layers of coal formed!
After the burnt mountain got exposed by erosion processes, oxidation of iron and manganese took place, giving it it’s purple and reddish glow. The entire place can be appreciated even more from the air, where you can see the full pallet of colours of the surroundings. It almost looks like an exquisite natural painting with all the colours you can imagine present in the landscape. A truly unique place!
TIP: About 800 meters from the Burnt mountain, you can check out the ‘valley of the organ pipes’. You can admire some impressive dolerite columns here, which are hidden away in a small gorge.
Noraly, I thoroughly enjoyed this blog posting and while reading placed myself in each locality and allowed my memories and feelings to merge with your words. My favourite in your list is Burnt Mountain, a place I first visited many years ago and felt then a measure of mysticism. Perhaps it was the late hour with the sun dipping behind the mountains and highlighting the colours, or it was the whispering evening breeze, but it felt surreal and very special. I especially enjoyed the drone flight you made over Burnt Mountain. Another favourite not on your list was the Oanob river valley, (you went past there after calling in at Rehoboth for petrol on your way to Spreetshoogte.) I was involved in the geotechnical investigation for the dam foundation there and was touched by the beautiful colours and eroded forms of the exposed quartz-phorphyry and subordinate green schist in the river bed.
Thanks CJS, Namibia is amazing indeed!
Noraly - I absolutely love your passion for the geology of this planet we live on! As an engineering geologist for 44 years now by profession and passion I also have an insatiable curiosity and fascination as to how the stunning landscapes we see everywhere formed. When my daughters were still at home and we would take our roadtrip vacations I can still hear them saying "Dad, do we really need to stop AGAIN so you can get a picture of that incredible example of some geolgic feature??" All I can say is that I admire you so much for following all of your passions and encourage my girls to follow theirs. You go Noraly!!
Great article Noraly. Your story telling skills bring the traveling experience to life. I enjoy driving around the Namib desert religiously. Just to add to your great article, check a typo on the name for the research center, it should read Gobabeb.
Thanks Simbi, I changed the typo right away ;-)
Thanks so much for taking the time to write such detailed but understandable explanations, super interesting! 🇬🇧🏍
Noraly thanks for the beautiful pictures and movies. When I watch your movies, In My brain I’m in the country. I like your proffesionality.
Noraly I would love to try help you get your long range tank, I assume it is coming through Johannesburg's mail centre, I do have some contacts that can help speed up the clearance if you would like :)
Thanks for the offer, but I am doing fine so far with the two spare bags :-)
Noraly thanks for this blog, it's a fine piece about all the amazing things to see in Namibie and how they originated.
Great read! Namibia is top of our list too and we hope to explore it next year :-)
Thank you for your wonderful comments! So happy to hear that you enjoy this 'educational' blog ;-)
Although I am not a geologist like you, I am fascinated by what I see in the landscape when I travel, particularly on my bike.The information you provide on your travels is outstanding and can turn a sometimes bland landscape into a much more interesting ride. You talked about those sand dunes. We have sand dunes here in the middle of our Rocky Mountains in Colorado. It is, indeed, a strange place to see them. It was the result of water and wind creating and pushing them up against our Sangre de Cristo Mountain range. When you come to the U.S. you may want to consider this top in our Rockies. Thank you, Noraly, for your fascinating videos!