How Was Victoria Falls Formed?
How was Victoria Falls formed is an incredible story – this awe-inspiring waterfall was formed over thousands of years. How? The surge of millions of tonnes of water eroding rock has created its current appearance and position on the Zambezi River.
The waterfall that is the major tourist attraction in Southern Africa, seen by thousands of sightseers every year, did not always look like it does today. The story of how Victoria Falls was formed over the ages and how it has evolved is a fascinating tale.
The waterfall has taken thousands of years and millions of tonnes of water to reach its current appearance and position on the Zambezi River. It is truly an ancient phenomenon that still creates awe in everyone who sees it.
The question “how was Victoria Falls formed?” is answered right here – read on for a full explanation.
Victoria Falls Geology
How did Victoria Falls form and how long ago was it created?
In the Jurassic period of Earth’s evolution, volcanic activity in the region deposited thick basalt molten rock that then solidified. This was the start of the geology of Victoria Falls.
This bed of basalt is approximately 305 meters thick and the Zambezi River flows over this volcanic rock for 209 kilometers. This flat basalt sheet extends as a flat plateau for hundreds of kilometers in every direction surrounding the falls.
The Zambezi river widens considerably before reaching the waterfall making it a spectacular sight in itself. A characteristic of the river’s course is the many little islands dotted throughout its journey.
These islands increase in number as the river nears the waterfall and are even found right at the waterfall’s edge. These are home to a wide variety of birds through the rivers course.
How Are Gorges Formed?
A gorge is a narrow valley with steep sides, generally with a stream or river running through the bottom of it.
Gorges are formed by the intervention of several geological occurrences.
- Tectonic activity
- Collapse of caverns
The most common gorge creator is erosion by water – exactly the method of creation of the Victoria Falls.
A gorge is the result of a change of rock type, generally a softer rock, at the site of a waterfall. The pressure of the falling water erodes the softer rock creating a deep scour in the earth. This erosion creates rockfalls that cut back into the earth eventually forming a deep chasm with steep sides – a gorge.
Now let’s find out how Victoria Falls was formed.
Formation Of The Gorges Below The Waterfall
The formation of the gorges is an important part of the story of the waterfall.
During the solidification process of the basalt molten rock, large cracks in the hard basalt developed. These cracks were subsequently filled with a softer sandstone rock over time.
It is commonly surmised that movement in the earth in an earlier geological period changed the rivers’ original course from running south-east to a more solid easterly direction. This newly diverted river then winds its way over the hard basalt and the many cracks filled with softer sandstone.
With the Zambezi River finding its way from its source to the ocean on its new course, the erosive power of the currents did a lot of work on the river.
The seasonal water flow eroded the soft sandstone from the cracks or basalt fissures. This removal of the soft earth from a large deep crack formed the first of many wide waterfalls that were still to come.
This repetition of this process created the zigzag gorges that originally were seven previous waterfalls.
Bear in mind that the erosion of the sandstone was a very slow process, taking hundreds or thousands of years in some cases, to form a waterfall.
The Gorges At Victoria Falls
The Victoria Falls formation we see today took place over a period of approximately 100 000 years.
There have been seven different waterfalls as the Zambezi River carved itself a path through the basalt rock of the plateau. This constant water erosion succeeded in pushing the current waterfall upstream by 8 kilometers from the original falls – creating a series of deep gorges.
This type of geology is a remarkable natural phenomenon. At Victoria Falls it can be seen in the zigzag formation of the gorges below the waterfall, which cover a distance of 150 kilometers downstream.
Looking at the sizes of these fissures it is safe to say that there has been a wider waterfall than the present one we see today. That is quite an amazing thought – that there has been a bigger waterfall than the one we see today.
The water torrent that gushes through these deep fissures creating rapids is considered to be one of the most exciting in the world, boasting some Class 5 rapids.
Today, we make use of the incredible depth and width of the gorge with high-wire and adrenaline activities for the thrill-seekers. These include the Victoria Falls gorge swing, Victoria Falls bungee jump, and zip line.
These gorges are also a haven for raptors who relish the wind eddies and vertical 125 meter high cliffs. These cliffs are breeding grounds for four species of endangered birds. The Taita Falcon, Black Eagle, Peregrine Falcon, Augur Buzzard, and the Black Stork appreciate these conditions too.
After leaving these narrow gorges, the river naturally widens out and slows down to its gentle meander through the African plains to Lake Kariba 200 kilometers downstream.
Finding out how was Victoria Falls created is fascinating, and it is still a work in progress too.
Collectively these gorges are commonly referred to as the Batoka Gorge, but officially each gorge is numbered in order starting from the youngest, which is the current waterfall, known as the First Gorge. Each of these gorges represents a past site of a waterfall.
- Gorge 1 – the site of the waterfall
- Gorge 2 – 2.15 kilometers long and spanned by the bridge
- Gorge 3 – 1.95 kilometers long
- Gorge 4 – 2.25 kilometers long
- Gorge 5 – 3.2 kilometers long
- Songwe Gorge – 3.3 kilometers long and the deepest of the gorges
Devils Cataract: The Beginnings Of A New Gorge and Waterfall
The Devils Cataract Falls on the far left edge of the falls is believed to be the start of the next fissure being eroded by the pounding of ceaseless water.
This section of the waterfall is the first sight you will see on your walk along the the long expanse of falling water into the gorge.
Experts say that this mini waterfall that is separate from the rest of the waterfall will cut diagonally behind the existing waterfall. Essentially this is the start of another gorge for the Zambezi River to thunder through.
This new development will demonstrate in real-time the geology of how Victoria Falls was created.
Unfortunately, we will never see this happen in our lifetime.
Over the next hundred years, the ever-progressing erosion of rock from the water flow will slowly wear away at the rock behind the current waterfall, which will eventually look very different to what it does now.
But whatever happens, the mighty river will continue to flow over the edge of a chasm and create an incredible sight for us to see for many, many years to come.