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Is Winneshiek County home to valuable minerals? The USGS and the University of Iowa are trying to find out

Posted: Tue, Jan 8, 2019 11:23 AM
The Decorah crater

University of Iowa geologists are conducting research to determine if Winneshiek County and the rest of Northeast Iowa has copper, nickel, platinum and other metal deposits.

"If the Iowa formation is a similar age as the Duluth Complex, this is promising for having similar types of minerals," says Iowa Geological Survey geologist Ryan Clark.

The minerals matter because they're used for industrial,medical, technological and energy-generation purposes. Platinum and its associated metals are used in catalytic converters for vehicles and may have a potential use in hydrogen fuel cells. Lithium is commonly used in batteries that power a host of electronic devices. Global demand for these minerals is increasing.

The U.S. Geological Survey's Mineral Resources Program is particularly interested in the Northeast Iowa region.  In 2012 it conducted the first airborne survey of the terrain around Decorah, which yielded a more detailed picture of the underlying geology, including the identification of the horseshoe-shaped Decorah Complex.

The USGS conducted a second survey in 2015 over a larger area that included Elkader, Manchester, and Vinton. That survey also showed geologic features such as rings and horseshoe shapes, which are similar to the Decorah formation and other complexes around the world that have economically valuable mineral deposits.

However, the surveys did not date the Northeast Iowa Formation, so USGS asked the University of Iowa for help.  Clark says if the core drilled near Elkader is shown to be of the same age as the Duluth Complex, he would like to seek funding to drill a second core in the Northeast Iowa Formation.

"This could be a massive economic boon to the state," he says.