The Geological History of The Victoria Africa Falls

Victoria Falls, locally known as ‘Mosi-oa-Tunya’ meaning “The Smoke that Thunders” is a waterfall located at the Zambia/Zimbabwe on Zambezi River. The Falls’ history is represented by a series of incredible geological events spanning for over 180 million years. Let’s go down the geological journey of the great “Mosi-oa-Tunya”.

Volcanic Eruptions and Gondwana Splitting Effect 

It started with successive volcanic eruptions that discharged lava over large areas and resulted into formation of a basalt layer that was approximately 300m thick. As the lava cooled, cracks started forming mostly in east-west direction. Approximately 11 million years ago as the super continent, Gondwana started breaking up into the continents; these giant cracks deepened and were slowly filled by soft clay-like sediments overtime.

Victoria Falls: The Tectonic Uplift Effect

Geologists argue that initially, Upper and Lower Zambezi were two different rivers. The upper Zambezi flowed across the Kalahari into the current Limpopo River, while Lower Zambezi occupied its current system. The geological event that followed (about 15 milions years ago) was a major tectonic uplift of what is now central Zimbabwe, creating a ridge known as the Zimbabwe-Kalahari Axis; that totally separated the Zambezi and Limpopo systems and resulted to the formation of a huge inland lake. It is believed that the lake could have been larger than the present-day Lake Victoria in East Africa.

The lower Zambezi gradually eroded back into the ancient lake (about 5million years ago), causing the lake to spill over. The flood water connected the upper and lower Zambezi, leaving behind an emptied lake (Makgadikgadi Pans). The river flowed over the hard basalt eroding sediments settled in the deep cracks leading to creation of deep gorges and formation the first Victoria Falls. Overtime, this erosion has lead to formation of a series of Falls with the current being the eighth incarnation of Victoria Falls, which formed about 100 thousand years ago. The waterfall has already started cutting back the next incarnation. This incarnation is believed to be on the largest line of weakness across the river. This means that the future of the Falls can only get more spectacular.

Read more about interesting geologies in Africa through this link: https://www.mininghubafrica.com/category/geology/