The Witwatersrand Basin represents the world’s richest gold province. Some 40-50 % of all the gold ever mined on Earth has been produced from the basin which is roughly an amount of 45 000 to 50 000 tons, at an estimated value of more than 50 billion US$ at a gold price of US$ 310 per ounce. The remaining gold reserves of the Witwatersrand Basin are estimated at 45% of the world’s known total reserves. Currently mined strata in the northern part of the Witwatersrand Basin generally dip between 15 and 20 degrees south, towards the Vredefort dome. THE 6 MILLION PASCALS OR ATMOSPHERS OR GIGADOLLARS SHOCKWAVE IMPACT What we see at present of the Vredefort Structure, are the eroded "roots" of this structure at a level approximately 17 km below the point of the original impact. The greater part of the structure had been removed by erosion taking place over 1 600 Ma, whereas a portion is buried under later sedimentary rocks of the Karoo Supergroup. The impact scar we see today measures approximately 140 km across and magnificently displays a variety of shock-induced features, which were recorded in the upturned collar strata, and the granitic gneiss core of the structure. Two surrounding concentric rings with diameter of approximately 160 km can also be observed. Nothing of the meteorite remained and the only information is the projection of the size of the original crater, which is estimated at approximately 90 km in diameter and more than 20 km in depth. Following American speculations, one might conceive a subject with a diameter of 4 to 5, or even up to 10 km in diameter striking the earth with a velocity of 30 km per second (108 000 km/hour). On impact, a transitional crater is formed, which almost immediately is filled up by material falling from the steep sides. By this process, the diameter of the crater becomes enlarged. The thinner (and consequently lighter) crust of the earth at this point, becomes uplifted over a long period, floating higher on the heavier mantle material underneath the original crater. In the process when the crater is formed, immediately after impact, concentric rings are formed around the crater. The event took place before the continents, as we know it today, moved apart. Life on earth at that stage probably was confined to the most primitive forms, being stromatolite-building bacteria, and no great extinction was recorded. Stromatolites survived this catastrophe, as well as other "great extinctions" and can still be found today. This most probably was because they were widespread, living under a protective layer of water. Free oxygen only appeared probably during the following 600 Ma, to which the primitive organisms had to adapt. Multi-cellular life appeared only about 600 to 700 Ma ago. It can be speculated that the appearance of eukaryotic life forms after this impact, might be analogous to the emergence of mammals after the Chixculub impact some 60 Ma ago. Vredefort Dome, approximately 120km south west of Johannesburg, is a representative part of a larger meteorite impact structure, or astrobleme. Dating 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. Vredefort Dome is the oldest, largest, and most deeply eroded complex meteorite impact structure in the world. It is the site of the world’s greatest single, known energy release event. It contains high quality and accessible geological (outcrop) sites which demonstrate a range of geological evidences of a complex meteorite impact structure. The rural and natural landscapes of the serial property help portray the magnitude of the ring structures resulting from the impact. The serial nomination is considered to be a representative sample of a complex meteorite impact structure. A comprehensive comparative analysis with other complex meteorite impact structures demonstrated that it is the only example on earth providing a full geological profile of an astrobleme below the crater floor, thereby enabling research into the genesis and development of an astrobleme immediately post impacT

Most of the craters formed on its surface were 
therefore obliterated by erosion, or are now covered by subsequently 
deposited sediments. The processes of accretionary bombardment and the 
existence of ancient astroblemes, such as Vredefort, have only lately been 
recognised (French, 1990). According to estimates, more than 200 impact 
basins of greater than 200 km in diameter must have formed during the early 
stages of the world’s creation. Having left the largest of the preserved 
astroblemes, the Vredefort impact must be regarded as representing 
probably the largest recorded episode of explosive energy release on the 
earth’s surface. Obviously, all of the effects are not known yet, and the 
structure remains one of the greatest sources of future research and, 
hopefully, knowledge. 
(iii) The Vredefort Structure – outstanding worth from a scientific 
point of view 
Since the beginning of the 1900’s, numerous international and local earth 
scientists have studied various aspects of the Vredefort Structure. In 1925, 
two geologists, Hall and Molengraaff stated: ”To anyone occupying a suitable 
point within the central Vredefort granite, the grand simplicity of design at 
once suggests a correspondingly broad simplicity in the major cause.” Noting 
the similar ring-like features displayed by the craters on the moon, Boon and 
Albritton (1937) suggested that the Vredefort Structure was the scar of an 
ancient meteorite impact. Since it was scientifically described for the first 
time, the literature on the structure has become voluminous

The structure of Vredefort is fortuitously situated within the boundaries of the 
Central Rand Group of the Witwatersrand Supergroup, which is the greatest 
single gold deposit in the world. Since the discovery of the Witwatersrand 
around 1886, the greater Vredefort structure and the Dome area has been 
subjected to the search for new mineable areas on an intensive scale. This 
also entailed the drilling of hundreds of boreholes into the structure, as well 
as the obtaining of numerous geophysical profiles (Brink et al., 1997). It can 
be claimed that the Vredefort Structure is the best known and explored of all 
of the large astroblemes on earth. As their economic importance to various 
mining companies wanes, the results of all of this activity are only now 
becoming available to earth scientists doing research on the Vredefort 

Structure.