Critical minerals in and around the upper mississippi valley ZN-PB districtproject period: september 1, 2023 to august 31, 2026.

The Department of the Interior U.S. Geological Survey Office of Acquisitions and Grants awarded a $626,046 Cooperative Agreement under the Earth Mapping Resources Initiative (CFDA 15.073) to the University of Illinois. The project, titled "Critical Minerals in and Around the Upper Mississippi Valley Zn-Pb District", aims to geologically map and characterize the Upper Mississippi Valley Zn-Pb district in Illinois, Iowa, and Wisconsin. The key activities include mapping historic mines, boreholes, mineralization, and structural geology, while also collecting new geochemical data to assess the district's potential for critical minerals such as zinc, barium, uranium, cadmium, silver, gallium, indium, and germanium. The University of Illinois is collaborating with the University of Iowa and University of Wisconsin System on this 3-year project, which will deliver a GIS database, map, and interpretive report on the critical mineral resources in the region.

Purpose

The upper mississippi valley (UMV) ZN-PB district is one of the largest base metal districts in north america and the type locality for mississippi valley-type (MVT) deposits. IT covers more than 7,800 KM2 in northwest illinois, northeast iowa, and southwest wisconsin. The UMV ZN-PB district in this area has produced over 1.5 million short tons of zinc and 500,000 short tons of lead. The resource was estimated to contain over 1 million short tons of in place of zinc and lead. However, these unrecovered ores have been underestimated because of the lack of exploration using modern geochemical and geophysical methods. The ores contain 4 to 8 of ZN, and 0.5 to 1 of PB. Critical minerals of significance within the district include sphalerite and residuum associated with barite with the potential for other associated critical minerals. Although the MVT deposits in this district are relatively well studied, no reliable data are available on the distribution or the concentrations of critical minerals such as ZN, BA, u, CD, AG, GA, in, and GE-bearing minerals within umvt sphalerite ORE, and associated barite ORE. Several questions remain regarding the concentration of critical minerals, their variability, spatial distribution, and their overall paragenesis related to MVT mineralization. This project aims to sample MVT sphalerite and barite ores from outcrops and cores from across the UMV ZN-PB district extended to the quad cities area for geochemical analysis and a comprehensive evaluation of their critical mineral contents.

Activities

The illinois state geological survey (isgs) in collaboration with the wisconsin geological and natural history survey (wgnhs) and the iowa geological survey (IGS) proposes to undertake three major tasks in support of the earth-MRI project to geologically map and characterize the focus area of the UMV ZN-PB district in illinois, iowa, and wisconsin. The area is extended to the quad cities area in illinois and iowa, which the MVT mineralization extends. These tasks have been dovetailed to create a significantly improved understanding of the UMV ZN-PB district and provide crucial information for future critical mineral exploration. The three tasks are as follows:1. Mapping of the UMV ZN-PB district including historic mines, boreholes, mineralization, structural geology, and newly collected samples with geochemistry analysis.2. New geochemical data as well as petrographic, mineralogic and thermometric results, driven by the newly created map, will be used to fill data gaps and to define a better sampling strategy of minerals for resource assessments of critical minerals in the district.3. An esri file geodatabase including all data and a supplemental report that includes a high-level geologic interpretation that will provide context to the data.deliverables and outcomes: the isgs will deliver an arcgis database, a map of all georeferenced historic mines, boreholes, mineralization, structural geology, and newly collected samples with geochemical data of the UMV ZN-PB district, and a report. All data will be published in the report by the isgs within 2 years of delivery to the USGS.

Intended beneficiaries

This earth-MRI project will provide an opportunity to deliver unbiased information of unknown mineral resource potential in a region that has been largely mined for lead and zinc ores but in which the critical minerals such as ZN, BA, u, CD, AG, GA, in, GE, and rare earth elements have not been studied for their potential resource.

Subrecipient activities

This earth-MRI project will be conducted in partnership with the wgnhs and IGS.