Mineral deposits far below northeast Iowa may be worth billions

IOWA CITY — Some farmers call Iowa’s fertile soil “black gold,” but there may be realgold deep under all that dirt.

University of Iowa researchers are studying core samples that could unlock secrets to valuable riches more than a thousand feet down.

Ryan Clark, a geologist with the Iowa Geological Survey — an agency housed at the UI, says indications show a potentially large formation of minerals well below the surface of ten northeast Iowa counties.

“We just don’t know exactly what the rocks are that are down there,” Clark says. “They could be what are called platinum group element deposits, so things like platinum, palladium, gold, silver. There could be nickel, copper.”

The core samples were taken during the 1960s by a company that was prospecting for iron. Geologists are now studying those samples to determine if it’s similar to a massive formation of precious minerals beneath Duluth, Minnesota.

“What we’re hoping is that the information that we produce, a mineral company will see that this is worth investigating further,” Clark says, “and then the mineral companies themselves will do the drilling and the actual mineral exploration part.”

If further testing determines there’s a potential great wealth of minerals under a wide section of northeast Iowa, would that eventually lead to strip mining and giant holes in the region’s rolling hills?

“That’s a very valid concern,” Clark says. “From what I understand of this type of mineral extraction, it’s going to be entirely underground, so the surface expression will not be nearly as large a scale as what you see in the iron mines in Minnesota where they have tailings ponds that are a square mile or larger.”

Some estimates show the giant mineral formation under Duluth is worth more than one-trillion dollars, which is why Iowa geologists are so enthusiastic to explore in northeast Iowa.

“If our formation can be considered to be similar in the rock types and the mineral types and things like that, our formation could potentially be even larger in scale,” Clark says. “In theory, you could take that number and go up from there.”

The ten-county region being studied stretches from Decorah in the north, to Elkader and Manchester in the east, and as far west as Vinton.

Don’t go out with a shovel, hunting for gold, either. Clark says the top of the potential mineral formation is at least one-to-two thousand feet down. It’s from the Precambrian era, he says, or about a billion years old.