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Kilimanjaro gallery
Look who made it to the top of Kilimanjaro this week!
Kilimanjaro geology
Rising 4800m above the East African plains, 270km from the shores of the Indian Ocean and measuring up to 40km across, Kilimanjaro is a bizarre geological oddity, the tallest freestanding mountain in the world and one formed, shaped, eroded and scarred by the twin forces of fire and ice. It is actually a volcano, or rather three volcanoes, with the two main peaks, Kibo and Mawenzi, the summits of two of those volcanoes. The story of its creation goes like this:
The Rift Valley
About three-
The formation of Kibo and Mawenzi
Soon after Shira’s extinction, Mawenzi started to form following a further eruption
within the Shira caldera. Though much eroded, Mawenzi has at least kept some of its
volcanic shape to this day. Then, 460,000 years ago, an enormous eruption just west
of Mawenzi caused the formation of Kibo. Continual subterranean pressure forced Kibo
to erupt several times more, forcing the summit ever higher until reaching a maximum
height of about 5900m. A further huge eruption from Kibo 100,000 years later led
to the formation of Kilimanjaro’s characteristic shiny black stone – which in reality
is just solidified black lava, or obsidian. This spilled over from Kibo’s crater
into the Shira caldera and around to the base of the Mawenzi peak, forming the so-
Kilimanjaro’s glaciers
Today, Uhuru Peak, the highest part of Kibo’s crater rim and the goal of most trekkers, stands at around 5895m. The fact that the summit is around five metres shorter today than it was 450,000 years ago can be ascribed in part to some improved technology, which has enabled scientists to measure the mountain more accurately; and in part to the simple progress of time and the insidious glacial erosion down the millennia. These glaciers, advancing and retreating across the summit, created a series of concentric rings like terraces near the top of this volcanic massif on the western side. The Kibo peak has also subsided slightly over time, and about one hundred thousand years ago a landslide took away part of the external crater, creating Kibo Barranco or the Barranco Valley (home to one of the mountain’s more popular campsites). The glaciers were also behind the formation of the valleys and canyons, eroding and smoothing the earth into gentle undulations all around the mountain, though less so on the northern side where the glaciers on the whole failed to reach, leaving the valleys sharper and more defined.
You can find out more about the mountain’s glaciers by visiting the Kilimanjaro glaciers page.
Is Kilimanjaro now an extinct volcano?
While eruptions are unheard of in recent times, Kibo is classified as being dormant rather than extinct, as anybody who visits the inner Reusch Crater can testify. A strong sulphur smell still rises from the crater, the earth is hot to touch, preventing ice from forming, while occasionally fumaroles escape from the Ash Pit that lies at its heart.
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