Vredefort Dome World Heritage Site
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.
The 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.
Justification for Inscription
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. (Source: UNESCO)
The Vredefort dome in the Free State, South Africa, is the oldest and largest meteorite impact site (Asrobleme) in the world. Formed an estimated 2000 million years ago when a gigantic meteorite (larger than Table Mountain) hit the earth close to where Vredefort is today. The force of the impact opened up a crater, which is still visible, and is about 40km in diameter.
When visiting the area you will notice small hills in a large dome shape with beautiful valleys between them. Evidence has been found by geologists that the cause of this upliftment was an extreme impact event, caused by an asteroid some 10 kilometres in diameter. 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. For additional info see Vredefort Dome.