Origin of Kilimanjaro

Birth of Kilimanjaro

The formation of Kilimanjaro started 750,000 years ago, when it consisted of three large vents: Shira, Kibo and Mawenzi. Over thousands of years Shira eventually collapsed, becoming extinct; Mawenzi remained active a while longer but eventually also became extinct and began to erode; Kibo continued with massive eruptions around 360,000 years ago that released black lava over the Shira caldera, creating the area known today as the Saddle, at the base of Mawenzi. Kibo finally reached a height of 5,900 m and erosion helped create the tall jagged peaks of Mawenzi and Shira's plateau. Kibo meanwhile leveled out and was covered during the ages with ice and glaciers. Around 100,000 years ago a huge landslide created the Kibo barranco (a steep- walled ravine). Kibo's final eruption created the Ash Pit, the Inner Crater and the perfectly formed caldera.

Theory of Rift Valley

In order to understand the main forces that have helped build Mount Kilimanjaro we must first have an understanding of Plate Tectonics. This theory says that the Earth's crust is divided into a series of vast, plate like parts that move or drift as distinct land masses.

Destructive Margins
These Plates can be colliding, which is called a Destructive Margin or moving apart, known as Constructive Margins. Sideways movements can be found along the San Andreas Fault in California. Where they collide one plate moves under the other. This is similar to having two sheets of paper on a flat surface and slowly moving the edges closer together at first they buckle and then one slides under the other.

Constructive Margins
Where the Plates spread apart we get rifts or cracks in the Earth. The Mid Atlantic has a very old Constructive Margin which has created the Atlantic Ocean and which continues to spread today. Around 25 million years ago another Constructive Margin was created in East Africa we know it today as the Great Rift Valley. Just before that time East Africa was a great plain and it is believed that collision of the African and the Eurasian plate resulted in the rupture. As the plates "rebounded" the resulting rift caused weaknesses in side the Earth which led to the formation of many volcanoes in the region.

One such volcano is Mount Kilimanjaro. Mount Kenya is also a volcano and at one time it was higher than Mount Kilimanjaro. Since Mount Kenya is older it has been eroded by the elements and now Mt. Kenya is the second highest mountain in Africa, it sits on the equator at an elevation of 5199m (17,058ft.).

"The formation of the Rift Valley is in geological phenomenon which is still continuing. It is, surprisingly, slowly widening and eastern Africa may, in millions of year’s time, split off to form a new continent. The original violent crack that caused the Rift naturally weakened the earth's crust most where the valley was deepest. It is, therefore, in this area and radiating from this main valley that other major volcanic activity produced numerous volcanic formations." The greatest of these volcanoes is Mount Kilimanjaro.