Heart of Louisiana: Meteor Crater

It would have been catastrophic when it slammed into Louisiana more than ten thousand years ago.
Published: Feb. 26, 2023 at 5:21 PM CST|Updated: Feb. 26, 2023 at 10:38 PM CST

BATON ROUGE, La. (WAFB) - It would have been catastrophic when it slammed into Louisiana more than ten-thousand years ago. Scientists at LSU have found the remains of a large crater that they believe was caused by a meteor impact.

A few miles south of Greensburg, there is a noticeable dip in the road as you drive along Louisiana Highway 37, but it doesn’t seem out of place among the gentle hills of St. Helena Parish. Nothing seemed unusual until LSU scientists working for the Louisiana geological survey began mapping the area.

“While we were looking at the topographic maps, we noticed a very strange circular feature,” said Paul Heinrich.

This map, created with laser imaging, shows Highway 37 crossing the north end of that curious depression. This is the circle, more than a mile across, that caught the eye of Paul Heinric.

“Since there are no volcanoes in Louisiana and there are no salt domes in this part of Louisiana, we knew that something strange was happening,” Heinric said.

The only explanation Heinric could come up with was a meteor crater. It likely happened within the last ten to twelve thousand years, a time when primitive people inhabited the piney woods of St. Helena.

A meteor would have struck without warning, perhaps on a moonlit night. A large space rock is speeding toward the earth, and once it hits the friction of the earth’s atmosphere, the fireball is only seconds from impact.

“It would have been a very bad day for anybody within 20 or 30 miles of here,” Heinric said. “Probably like a small nuclear explosion, there would have been like a ten or 20-mile zone in which anybody or anything here would have been either killed or very badly injured,” he added.

The meteor that made this crater was no small piece of cosmic rock. In fact, when it slammed into the earth, it was at least a hundred feet in diameter.

That’s similar in size to the meteor that made this crater in Arizona. Heinric believes the Louisiana crater is slightly larger than this, but erosion and weathering in Louisiana’s soft soil have erased what was once a massive hole.

“This is a fracture here, this is a fracture and this is a fracture,” said Heinric.

Heinric has found evidence that proves his theory of a meteor strike. The impact fractured the iron-rich bedrock and superheated water bleached the sediment. Those fractures are clearly visible near the crater’s rim. The real proof is in tiny pieces of quartz that have similar shock marks and microscopic dark lines that confirm the impact.

“The only known manner in which shocked quartz is formed is either by meteorite impacts or nuclear tests,” Heinric said.

It’s the fingerprint of a prehistoric catastrophe, the only known meteor crater in Louisiana, and one of only 120 on earth. It’s an example of how we can still make fascinating discoveries about our past.

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