About the Dome - HEART OF THE CRATER

The Vredefort Dome is a UNESCO world Heritage Site mainly for its scientific value. The Citation below says the area is of “outstanding universal value”. It is also of major historical interest and marvellously scenic. It is one of more than 1000 sites throughout the world, designated for their cultural, historical, scientific and artistic value.

In the early 1990s the Dome was scientifically identified by a consensus of geologists. This followed a long debate spanning decades. In 2005 it was declared a World Heritage Site by UNESCO. Since then, concerns have arisen about threats to the integrity of the area, caused by mismanagement, pollution, and environmental degradation.

It took collaboration between geologists, conservationists and the Mandela government to have the area declared by UNESCO. It is now an increasingly popular destination for visitors who range from domestic and foreign tourists to researchers, school and university groups, writers and artists. The fascinating story of the impact and its long-term effects on the planet is told in our briefings and on tours.

UNESCO Citation

https://whc.unesco.org/en/list/1162/

Vredefort Dome
Outstanding Universal Value

“Vredefort Dome, approximately 120 km 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 yet found on Earth. With a radius of 190 km, 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 had devastating global effects including, according to some scientists, major evolutionary changes. It provides critical evidence of the Earth’s geological history and is crucial to understanding of the evolution of the planet. Despite the importance of impact sites to the planet’s history, geological activity on the Earth’s surface has led to the disappearance of evidence from most of them, and Vredefort is the only example to provide a full geological profile of an astrobleme below the crater floor.

“Criterion (viii): 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.”

Remarkable evidence of the impact: This quarried wall, a satellite site of the main Site, shows massive boulders embedded in what was molten glass. It is called pseudotachylite, or false volcanic glass. Our tours always visit this wall.

Threats to the Site

Worries about the future of the Dome are contained in various reports, the one below from UNESCO itself.

An inspection report raised serious concerns about conservation of the Dome. By 2022 the Site had still not been legislated in the South African Parliament. A Government Gazette in 2007 published draft regulations but negotiations between landowners and the State have not yet led to their promulgation.

The World Heritage Site (VDWHS) forms only a small part of the total crater structure which covers much of the central Highveld from Johannesburg to Welkom. The Site area is almost entirely in private hands. It covers is about 30,111 ha, comprising a core of 30,108 ha and 3 satellite components of 1 ha each. The main Site is surrounded by a 5 km buffer zone that is designed to ensure the property’s long term protection against external development threats.

The Vaal River is rapidly losing the ability to dilute or dissolve pollutants. Source: webnic.co.za

The Threats

A 2015 report by WebNic SA drew attention to the threats. Read it here.

We highlight these issues in Dome presentations in order to engage the public and raise awareness.

Prospecting for gold mining, with proposals for open cast mining
Developers seeking to get in ahead of any restrictions if and when the Site is legislated
Irresponsible tourism and other activities with no supervision
Loss of habitat due to overgrazing, degradation of wetlands and other factors
Poverty and unemployment contributing to urban blight
Serious pollution of the Vaal River by sewage and mining, industrial & urban waste
Delays and central State neglect of the area despite its tourism potential
Failure to educate the local populace and spread information

Educate to Protect!

Public education is the best tool to ensure conservation of this beautiful area. Visit, enjoy the environment, and help us to fight to have it properly protected.