Scientists say they’ve found new evidence of a 470-million-year-old meteorite crater in northeast Iowa. Paul Bedrosian is a geophysicist with U.S. Geological Survey. He says electromagnetic imaging provides strong support for the crater’s existence.
Bedrosian says the planet has a long history of meteorite hits, but they can be hard to find. “Preserved on earth today are less than 200 confirmed meteorite impact structures,” Bedrosian said.
“Our preliminary findings, assuming they’re confirmed, will add one to that record. The earth has suffered a much larger number of impacts over its history, however, plate tectonics – over time – serves to erase the evidence of many of those structures.” Researchers looking for underground minerals located the 3.5 mile crater near Decorah.
The crater is almost entirely underground. “Looking at an aerial image, you wouldn’t see anything,” Bedrosian said. “My colleague, Bob McKay at the Iowa DNR, has found one outcrop, but aside from that limited area, there’s no evidence of it above ground.”
The results are still considered preliminary. Scientists with the Iowa DNR first speculated in 2008 that a meteorite had once struck the region. That was based on data gathered from well drilling samples.