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SCIENCE

Ejecta discovered near site of ancient

meteorite impact in Vredefort

By Katherine Kornei

outh Africa’s Vredefort impact structure is the largest Precambrian, the researchers suggest.
on the planet, and researchers have now discovered The Vredefort impact structure is estimated to be between 180
Sthe first proximal ejecta possibly deriving from the and 300 kilometres in diameter — it’s believed to be the largest
cataclysmic impact. impact structure on Earth. But it doesn’t look at all like a crater. It’s
A meteorite impact is a colossal disruption — think intense far too old — and therefore too eroded — to have preserved that
ground shaking, sediments launching skyward, and enormous characteristic signature of an impact.
tsunamis. But evidence of all that mayhem can be erased by What’s visible instead is an arc of uplifted sediments. That
erosion over time. Scientists have now relied on clever geological material is part of the “peak ring” that formed within the original
sleuthing to discover impact ejecta near South Africa’s Vredefort crater. Such uplifted material is the calling card of a massive
impact structure, the site of a massive meteorite strike roughly impact, said Matthew S. Huber, a geologist at the University
2 billion years ago. These ejecta might hold clues about the of the Western Cape in Cape Town, South Africa. “If there’s a
composition of the object that slammed into Earth during the sufficiently large impact, there will be a rebound.”

Bull’s-eye-looking features
in South African rocks
might be a sign of a
nearby meteorite impact.
Credit: Matthew S. Huber

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