Vredefort warns of future impacts

16 August 2005

“Four minutes that literally shook the world resulted in the creation of an enormous impact crater,” says Prof Uwe Reimold, professor of Mineralogy in the School of Geosciences at Wits University. “The meteorite that crashed into the earth near Vredefort in the Free State is the single greatest geological catastrophe yet uncovered on our planet.”

Meteorite Impact! The Danger from Space is a new book on the Vredefort impact co-authored by Reimold and Prof Roger Gibson. The book explains how the lessons learned from the rocks around Vredefort are being used throughout the world to teach a new generation of scientists of the reality, and danger, of similar events in the future.

“The book reviews more than 200 000 years of human habitation in this area of exceptional natural beauty and biodiversity,” says Reimold. The impact area, known as the Vredefort Dome, was awarded Unesco World Heritage status in July.

“This history starts with the early San hunters, whose graceful art survives today on rocks formed during the impact event. The successive settlements of Sotho-Tswana, Afrikaner and British farmers are discussed, including the landmark wars that affected the region over the last three centuries.

“The book also documents the rich geological, archaeological, cultural and botanical heritage presented by the Vredefort region, opening up the information to non-geoscientists. It concludes with a guide to more than 20 sites that highlight the heritage of this area, a World Heritage Site,” Reimold says.

Bigger than the dinosaur killer

The Vredefort structure is the oldest and largest visible meteor impact crater in the world. At about 300km it diameter it is nearly twice the size of the Chicxulub crater, formed by the meteor impact that led to the extinction of the dinosaurs.

“The Chicxulub impact wiped out approximately 75% of all known life on Earth 65 million years ago,” says Reimold.

“In the more than 2 000 million years since the formation of the Vredefort structure, water, wind and ice have slowly eroded away the original crater, exposing its roots in a series of spectacular rocks.

“The outcroppings in the region around the towns of Vredefort and Parys, known as the Vredefort Dome, show the scars of the cataclysmic forces that accompanied the impact event.

“The rocks, ripped from the depths of the crust by the impact, also tell a far older story that stretches back to more than 3 500 million years ago, when the first continents formed on the primitive Earth, and to the time when fabulous gold deposits accumulated on the margins of the ancient Witwatersrand sea.”

 

  • Meteorite Impact! The Danger from Space and South Africa’s Mega-Impact, the Vredefort Structure by WU Reimold and RL Gibson. ISBN 1-919908-62-5. Contact Chris van Rensburg Publications on +27 11 726 4350 or visit the Johannesburg Planetarium.

 

SAinfo reporter

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