The Domaine du Meteore winery in southern France takes its name from a dramatic depression in the ground in which it grows grapevines. It turns out the name is more than a marketing ploy. The geologist and cosmochemist Frank Brenker from the Goethe University in Frankfurt says it has been proven.
Decades ago, geologists disagreed over how the 720-foot-wide (220-meter) and 100-foot-deep (30-meter) depression formed. Some thought it might have come from a meteorite impact. But others said no, thanks in part to the lack of a raised rim around the edge of the dip, and everyone just went along with it. Until now.
“Craters can form in many ways, and meteorite craters are indeed very rare,” Brenker said in a Goethe University statement on Wednesday. “However, I found the various other interpretations of how this depression could have formed unconvincing from a geological point of view.”
Brenker surveyed the depression and set out to find signs of a long-ago meteorite impact. It can be difficult to spot a meteor crater. Over time, erosion and other geological processes obscure the evidence. Brenker’s article on the French Winery Crater (PDF link) points out that small impact craters (below 300 meters in diameter) are very rare and it is difficult to prove their extraterrestrial origin.
An analysis revealed evidence of rocks cemented together, so-called breccias, which can be associated with meteorite impacts. Brenker, geophysicist Andreas Junge and a team of students went on an excursion to take a closer look. They measured a weakened magnetic field at the point. “This is typical of impact craters because the impact shatters or even melts the rock, which can then contribute less to the Earth’s magnetic field,” says the university.
The team used a powerful magnet to pull up small globules of iron oxide, another key component found in other impact craters caused by meteorites. A combination of geological and mineralogical evidence points to a space rock as the culprit behind the depression.
Domaine du Meteore has embraced its otherworldly origin story. “These are wines from another dimension,” the winery proudly announces.