Vredefort Dome South Africa Africa Wonders, South Africa Attraction Vredefort Dome, Vredefort Dome Guide, Vredefort Dome South Africa Africa Tourist Guide
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Blyde River Vredefort Dome

Vredefort Dome, approximately 120km south west of Johannesburg, is a representative part of a larger meteorite impact structure, or astrobleme and has been declared South Africa's seventh World Heritage Site (2005).

The impact created a crater some 70 km in diameter and 16-18 km deep and caused a tremendous shift in in the earth's crust across a radius of over 150km.
From the air, a partial ring of hills can be seen clearly. These hills form an arc to the north and west of Vredefort and Parys, centring on Vredefort. This area is known as the "Vredefort Dome".

 
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Vredefort Dome History

Blyde RiverDating back 2,023 million years, it is the oldest astrobleme found on earth so far. With a radius of 190km, it is also the largest and the most deeply eroded. Vredefort Dome bears witness to the world’s greatest known single energy release event, which caused devastating global change, including, according to some scientists, major evolutionary changes.

It provides critical evidence of the earth’s geological history and is crucial to our understanding of the evolution of the planet.

Despite their importance to the planet’s history, geological activity on the earth’s surface has led to the disappearance of evidence from most impact sites and Vredefort is the only example on earth to provide a full geological profile of an astrobleme below the crater floor.

When visiting the area you will notice small hills in a large dome shape with beautiful valleys between them.

The ring of hills we see now are the eroded remains of a dome created by the rebound of the rock below the impact site after the asteroid hit. The original crater, now eroded away, is estimated to have been 250 - 300 kilometres in diameter. Some 70 cubic kilometres of rock would have been vaporised in the impact.

The Vredefort structure is currently regarded the biggest and oldest clearly visible impact structure on Earth. It just beats the Sudbury impact structure in Canada for this ranking. The Sudbury structure is some 200 km in diameter and is estimated to be 1.85 billion years old.

Within the ring of hills at Vredefort is found granitic gneiss rock. The force of the impact produced deep fractures in the underlying rock. Rock melted by the impact flowed down into the cracks, producing what are now exposed as ridges of hard dark rock - the granophyre dykes. This contrasts with normal geological dykes, where molten rock from deeper in the earth has flowed upwards through cracks.

Many activities can be enjoyed in the area on the Dome Bergland Meander. From river rafting, river tubing, abseiling, horse riding, mountain biking, archery or walking.

Or visit the Anglo Boer War sites, the the largest wild olive forest in South Africa at Venterskroon, or a visit to a distillery where traditional South African "witblits" (extremely strong spirits) is made.

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Discovery of Vredefort Dome

From a high altitude the partial ring of hills in the Vredefort Dome bear a strong resemblance to the larger, near-circular ring of hills to the north and south of Vredefort. These are the Magaliesberg hills, on the northern side of this ring, cutting through Pretoria, and the the Witwatersrand ridge, on the southern side of this ring, cutting through Johannesburg. The Witwatersrand ridge, surrounding this uplifted area, is known as the "Johannesburg Dome".

The gold mine dumps of Carletonville can be seen west of Johannesburg and due north of Vredefort. The gold mines of Klerksdorp and Welkom lie north west and south west of Vredefort, and their dumps are also easily seen, forming a half ring of gold mines around Vredefort.

The Magaliesberg - Witwatersrand feature is the result of natural upliftment of sedimentary sandstone layers, what was once the bottom of a sea.

The Magaliesberg rock layers slope down to the north, while the Witwatersrand rock layers slope down to the south. The "Johannesburg Dome" in the center this feature is occupied by the Achaean granitic crust, some 3000 to 3400 million years old.

The same rock layers seen in the Witwatersrand are found in the Vredefort dome hills, but here they are found standing nearly vertically - the result of extreme upliftment.

The Vredefort structure is currently regarded the biggest and oldest clearly visible impact structure on Earth. It just beats the Sudbury impact structure in Canada for this ranking. The Sudbury structure is some 200 km in diameter and is estimated to be 1850 million years old.

Evidence of four impacts even older than than Vredefort, that occurred 3200 to 3500 million years ago, has been found in the greenstone rocks around Barberton in Mpumalanga, South Africa, and corresponding rocks in the eastern Pilbara block of Western Australia. However, these impacts are no longer recognizable as structures on the surface like those in the Vredefort area.
 
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Getting There
The dome is situated about 120 km south west of Johannesburg.
Follow the N1 south to Parys and then Vredofort. It is a short distance away from the N1 highway and clearly signposted.
 
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