Everything Everywhere Daily: History, Science, Geography & More - The East Africa Rift (Encore)

Starting point is 00:00:00 The following is an encore presentation of everything everywhere daily. Today, there is a giant rift that is tearing the continent of Africa apart. And I mean that quite literally because the rift isn't cultural, economic, or political, it's geologic. In several million years, Africa will literally split into two continents. And while the process will take a long time, you can see ample evidence for it right now. Learn more about the East African Rift and how it's shaped the modern continent of Africa on this episode of Everything Everywhere Daily. What if your perceptions about the past were wrong?

Starting point is 00:00:52 ThruLine is a podcast that takes you back in time to uncover the parts of the story that may have gone unnoticed. It effectively turned day into night. And how it shaped the world now. Time travel with us every week on the ThruLine podcast from NPR. Geologically speaking, Africa is a very old continent. You don't see many major mountain ranges in Africa for this reason. Because it's so old, there has been more time for erosion, which has made it relatively flat.

Starting point is 00:01:26 However, there is active geology going on in Africa. It's just different than the type which is going on in the rest of the world. If you remember back to my episode on plate tectonics, the Earth's tectonic plates are responsible for most of the earthquakes and volcanoes on the planet. A collision of tectonic plates often forms mountain chains. For example, the Himalayas were formed by the Indian subcontinent, colliding with Asia. Most of the ring of fire around the Pacific is the result of an oceanic tectonic plate subducting under a continental plate. But if plates are colliding with each other,

Starting point is 00:01:59 then that means somewhere else they have to be splitting apart. These regions are called riffs. Most of the riffs on Earth are found in the middle of the oceans. Both the Atlantic and Pacific have major riffs which run for thousands of miles. There are actually only two places on land where you can see two tectonic plates splitting apart. The first is in Iceland, which is actually just a part of the Mid-Atlantic ridge, which goes through the ocean. And the other is in East Africa. In the case of East Africa, it isn't two different plates moving apart from each other. It's actually one large continental plate that's literally splitting apart.

Starting point is 00:02:36 It's the result of the interaction between three or two, depending on how you define it, tectonic plates. There is a triple junction of plates located where the Arabian Peninsula comes closest to Africa, and where the Red Sea and the Gulf of Aden meet. Here, the Arabian plate meets the point where the African plate is starting to split in two. On the east is the part of the African plate now known as the Somali plate, and to the west is the part of the African plate, known as the Nubian plate. The entire East African rift that I'll be talking about is actually part of a larger Rift system that extends all the way up the Red Sea and is also responsible for the Dead Sea between Israel and Jordan.

Starting point is 00:03:17 The reason I'm doing an episode on the East African Rift is that so many of the interesting geological formations in Africa are all due to the Rift. Once you understand the Rift, you can look at a map and clearly see where it runs. The start of the Rift begins at the closest point of land to the Triple Junction. This is the area known as the Afar Triangle.

Starting point is 00:03:39 The Afar Triangle consists of the nations of Eritrea, Djibouti, Ethiopia, and Somalia. The rift then goes straight through the country of Ethiopia and then snakes down the western side of Kenya until it gets to a point approximately parallel with the southernmost part of Lake Victoria. This section is the eastern rift, also known as the Gregory Rift, named after John Walter Gregory, the geologist that first studied it. Then there is another section which is west of Lake Victoria, starting roughly at the northernmost part of the lake. This runs down the border of the Democratic Republic of Congo and Uganda, and then Tanzania, and then Zania, and then Zan. Bambia before turning and going down the length of Malawi and then cutting across Mozambique. This is the Western Rift or the Albertine Rift.

Starting point is 00:04:24 So if you can envision this, there are two sections that are not contiguous that run parallel to each other for a stretch on either side of Lake Victoria. The area around Lake Victoria has been dubbed a microplate, and it's actually rotating counterclockwise from the two rifts on either side of it. The average rate at which the plates are pulling apart is approximately 7 millimeters per year, and that may not seem like much, but in geologic terms it's actually pretty rapid. It means that every so often, in segments of the rift, there will be new cracks and chasms that form. For example, in 2018, a new crack in the ground appeared out of nowhere in southwestern Kenya.

Starting point is 00:05:05 The crack was 50 feet or 15 meters deep and as wide as 60 feet or 18 meters across. Geology aside, the reason I wanted to do an episode on the East African Rift is that the Rift is responsible for, or is the location of, so many of the notable features on the African continent. So let's start with the northernmost section of the Rift in the Afar Triangle. This is the location of the Danak Hill Depression. The Danakil Depression is one of the lowest, driest, and hottest places on planet Earth. I actually visited the Danakil Depression in Ethiopia several years ago, and it was on unlike any experience I've ever had traveling.

Starting point is 00:05:44 I witnessed temperatures of 50 degrees Celsius or 122 degrees Fahrenheit, which was the hottest that I've ever experienced. The village of DeLal in the Depression is the hottest place in the world where people actually live. There are incredible sulfur springs that exist and have some of the most acidic places on the planet. And it's also the home of the Erda Ale volcano. Erda Ale is unlike other volcanoes in that it's actually just an open pool of lava that can be access by walking up to the lip of it. The Danakil Depression is also home to one of the most ancient salt harvesting industries in the world. Men there still chop slabs of salt from the ground

Starting point is 00:06:22 and ship it to a salt processing center via camel caravan. In southern Ethiopia is the Omo Valley, also created by the Eastern Rift. The Omo Valley is home to many people who still live according to their traditional ways, including the Kara, Hamer, Surma, Mercy, Dasanetch, Bana, Simi, Ibori, and Nagayatom peoples. They're often known for their elaborate body adornments, including lip plates and ritual scarring. As the rift moves south, going through Ethiopia, you'll find a series of small rift lakes. When you reach the border of Kenya, you'll find the first of the major rift lakes in Africa, Lake Turkana, and more on rift lakes in just a bit. As the eastern rift goes through Kenya and eventually Tanzania, immediately to the east, you'll find several of the tallest peaks on the continent, including Mount Kenya and Mount Kilimanjaro, just over the border in Tanzania.

Starting point is 00:07:11 These mountains are actually volcanoes that were created as a direct result of the movement of the plates in the Rift Zone. Also in this area, you'll find Serengeti National Park in Tanzania and the Masai Mara Game Reserve in Kenya. The East African Rift also literally defines the Angoro-Norro Crater. The rift creates the eastern and southern walls of the crater. Collectively, these places are the home of the Great Migration, where approximately 1.8 million wildebeests migrate every year from Ngoro-Angoro to Masay Mara, where they seek better grazing grounds. Not far from the Angoro-Angoro Crater is the Olduvai Gorge. The gorge is part of the Rift system and was where fossils of some of the oldest human

Starting point is 00:07:52 ancestors were found. As I mentioned before, between the southern part of the eastern rift and the northern part of the western rift, lies Lake Victoria, one of the largest lakes in the world. Victoria is not a rift lake per se, but it was created because of a drainage basin that arose due to the eastern and western rifts on either side of it. To the west of Lake Victoria starts the western rift. Here you can very clearly see on any map of Africa where the rift runs because it's defined by a series of rift lakes. Starting along the border of Uganda and the Democratic Republic of Congo

Starting point is 00:08:28 and going south, you'll see a chain of long, slender lakes. These lakes are literally formed by the plates splitting apart and the gaps between them being filled with water. The lakes in the western rift are much larger than those found in the eastern rift, and they include some of the world's largest lakes. In the north, you'll find Lake Albert, Lake Kivu, and Lake Tanganyika. Lake Tanganyika is the largest of the rift lakes and the second deepest lake in the world after Lake Baikal and Russia. The southern rift lakes include Lake Rukwa, Lake Malawi, Lake Malobe, and Lake Chilwa. Lake Malawi is actually the second largest of the rift lakes.

Starting point is 00:09:06 collectively, the rift lakes are home to an incredible amount of aquatic diversity and species that are found nowhere else on Earth. They're also home to over 800 species of cichlid fish, which are popular fish for home aquariums. These lakes also have hidden dangers lurking under the surface. If you remember back to my episode on Lymnick eruptions, some lakes such as Lake Kivu have enormous amounts of methane in their lake bed, which, if it ever came to the surface, would be an enormous disaster for those living around the lake. Just as the eastern rift was responsible for mountains, so too is the western rift. The Varunga Mountains can be found mostly in the Democratic Republic of Congo with small parts in Uganda and Rwanda.

Starting point is 00:09:48 The Varunga Mountains are volcanic, just like their counterparts to the east, and they're also the home to the mountain gorilla. I've just gone over a whole lot of things pretty quickly, but the point I wanted to make is that so many of the highlights of Africa are all the result of a single geologic feature that runs throughout the length of the continent. Large lakes, tall mountains, exceptional wildlife, unique cultures, and even human evolution, have all come about, directly or indirectly, from the splitting of the African tectonic plate. In addition to everything I've just mentioned, the East African rift also holds a great deal of future potential.

Starting point is 00:10:26 Earlier, I mentioned that the only other place on Earth where you could see a rift like this on land was in Iceland. It just so happens that Iceland produces the highest, percentage of geothermal energy in the world, and that is not a coincidence. A rift signifies a thinning of the earth's crust, which makes it easier to tap into the heat which exists below the surface. That means that much of East Africa along the rift has the potential to become a geothermal powerhouse, as it is vastly larger than all of Iceland. Looking forward into the very distant future, the East African Rift will completely reshape the map of Africa. millions of years from now, most of the African Rift Lakes will be connected, forming a massive inland sea.

Starting point is 00:11:09 And at some point, in tens of millions of years, East Africa will completely break off from the rest of Africa to form a new continent. We have no idea what the shape of this new continent will be, as it's impossible to predict where the fracturing and the rocks might take place. It's possible that it could be one landmass or it could splinter into several different islands. And it will also mean the creation of a new ocean or sea between the two. two new continents. The East African Rift is one of the most important geologic features on Earth. And the next time you look at a map of Africa, or even a map of the world, take a closer look at the region of East Africa, and you'll find it impossible not to see this feature that has always been there. The executive producer of Everything Everywhere Daily is Charles Daniel.

Starting point is 00:11:56 The associate producers are Benji Long and Cameron Kiever. I want to give a big shout out to everyone who supports the show over on Patreon, including the show's producers. Your support helps me put out a show every single day. And also, Patreon is currently the only place where Everything Everywhere or Daily merchandise is available to the top tier of supporters. If you'd like to talk to other listeners of the show and members of the Completionist Club, you can join the Everything Everywhere Daily Facebook group or Discord server. Links to everything are in the show notes.

Everything Everywhere Daily: History, Science, Geography & More - The East Africa Rift (Encore)

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