French winery is site of a meteor crater
Domaine du Météore in the south of France is a winery named for a peculiarity in the local landscape. The vineyards lie within a 650-foot-wide (200-meter-wide) depression and in the surrounding foothills. People in the area long believed the unusual feature was the result of a meteorite impact. And now scientists have confirmed their suspicions. Researchers from Goethe University Frankfurt announced on February 23, 2023, that their rock and soil analyses of the site shows that an iron-nickel meteorite crashed to Earth here thousands of years ago. Only three meteorite impacts in western Europe were previously known; this discovery brings the total to four.
While Earth was frequently bombarded by space rocks in its past, traces of those impacts remain elusive today. Erosion and plate tectonics do a good job of wiping away evidence of impacts. The Earth Impact Database lists all 190 known craters that resulted from meteorite impacts. Now, another one will join their ranks.
Geologist and cosmochemist Frank Brenker of Goethe University Frankfurt led the study. He will present his findings at the 54th Lunar and Planetary Science Conference in mid-March.
Vacationing at a meteor crater
Some scientists proposed the idea that the region was the site of a meteor crater in the 1950s. However, two observations led to the dismissal of that idea. The first was that the crater doesn’t have an elevated rim. And the second was that they couldn’t find evidence of a magnetic anomaly. Thus, the study of this crater ended until Brenker took it on. Brenker said:
Craters can form in many ways, and meteorite craters are indeed very rare. However, I found the various other interpretations of how this depression could have formed unconvincing from a geological perspective.
Brenker was on vacation when the Domaine du Météore caught his attention. While there, he and his wife collected rock samples for future analysis. Their preliminary findings indicated the meteor strike was likely. As Brenker said:
The microanalysis showed that dark-colored layers in one of the shists, which usually simply comprise a larger percentage of mica, might be shock veins produced by the grinding and fracturing of the rock, which in turn could have been caused by an impact.
In addition, their samples showed evidence of breccia. Breccia is rock made of broken, fragmented debris cemented together in events such as meteorite impacts. So, Brenker assembled a team to follow up with detailed field work.
Brenker returns to Domaine du Météore
Brenker and his team returned to Domaine du Météore the next year. In their studies, they found that Earth’s magnetic field is slightly weaker in the crater than in the surrounding region. This was the magnetic anomaly researchers had missed 70 years earlier. Scientists expect this kind of magnetic anomaly in impact craters. When an impact shatters or melts rock, it then contributes less to Earth’s magnetic field.
In another experiment, the team used strong magnets to attract tiny iron oxide spherules just one millimeter (three-hundredths of an inch) in diameter. Back at the lab, they found that the spherules contained nickel-bearing iron and a core of minerals, both typical of an impact site.
Lastly, the team found numerous shock microdiamonds. These itty-bitty diamonds form under high pressure during impact.
Brenker explained their findings:
Such microspheres form either through abrasion of the meteorite in the atmosphere or only upon impact, when a large part of the iron meteorite melts and then reacts with the oxygen in the air. On impact, material shattered at the point of impact might then also be encased. This, together with the lower magnetic field and the other geological and mineralogical finds, allows us to draw hardly any other conclusion: a meteorite did indeed strike here.
Brenker said:
Every visitor can experience here the immense energies released upon such an impact.
Plus, the wine probably helps visitors experience positive energies, too.
Bottom line: Scientists have confirmed that Domaine du Météore, a French winery named for a depression in the landscape, was indeed the site of a meteor crater.
Via Goethe University Frankfurt
Read more: The 5 impact craters on Earth that highlight our wild past
