There was once a huge rift between Minnesota and Wisconsin. And it had nothing to do with the Vikings and the Packers.
More than one billion years ago the magmatic and dynamic Midcontinent Rift System tried – and ultimately failed – to split the continent between (what’s now) the two states. Up flowed huge amounts of magma, which brought with it the rich mineralization we know today – copper, nickel, platinum group elements and titanium.
And going back even further – more than two billion years ago – Minnesota’s bedrock experienced volcanic eruptions, tectonic collisions,and the melting and metamorphism of rocks. All that prehistoric activity created ideal conditions for concentrating and distributing valuable minerals.
But knowing what’s where… is complicated. Unless you have access to cutting-edge technology. And we have that today.
Detailed Data
The U.S. Geological Survey funded a two-phase project to use magnetic imaging technology, deployed in aircraft, to gather detailed geophysical data and then conduct fine-scale mapping and analysis.
NRRI geologists conducted the physical and chemical characterization of drill core rock samples from areas identified by the aerial survey. They accessed the large drill core collection at the Minnesota Department of Natural Resources in Hibbing for this study.
“Our goal is to understand Minnesota’s geology with detail never before achieved,” said NRRI Economic Geologist, Joyashish Thakurta. “Our state is well known for its iron ore, but now we’ve expanded that profile while looking for critical minerals in eight different geological systems – especially in northwest Minnesota.”
The final report, “Preliminary Investigation of the Precambrian Geology of the Mentor Igneous Complex Focus Area in Minnesota,” was delivered in September 2024. NRRI’s collaborators were the Minnesota Geological Survey, University of Minnesota’s Earth and Environmental Sciences, Boise State University and the Minnesota Department of Natural Resources.
Critical Minerals
The effort in Minnesota is part of a national Earth Mapping Resources Initiative – called Earth MRI – a program led by the USGS to identify and assess domestic critical mineral resources. The initiative is a cornerstone of the U.S. strategy to reduce reliance on foreign sources, especially China, which are essential for:
- Clean energy (lithium, cobalt, rare earth elements for batteries and wind turbines)
- National defense (rare earth elements and titanium)
- High-tech industries (semiconductors, electric vehicles)
Early results show significant promise for mineral resources, especially around Minnesota’s Mentor Igneous Complex, southeast of Crookston (see map) making this area a strong candidate for future mineral exploration.
Modeling & Mapping
NRRI GIS Specialist Kristi Nixon worked with Thakurta to develop a “fuzzy logic” statistical model, which teases out more detail from the data. This online model shows the potential for the occurrences of critical minerals such as nickel, manganese, chromium, and vanadium in the Minnesota database. It has been submitted to USGS for publication as part of the overall Earth MRI program.
The U.S. Geological Survey has invested more than $2 million on this mapping effort in central Minnesota. In addition to critical minerals, it also informs understanding of water resources, groundwater pathways near legacy mining areas, parameters for infrastructure and land use planning, and potential risks of naturally occurring radon. All of these data will inform continued evaluation of the region’s resources.