Geochemical and geochronological mapping of the western spirit lake tectonic zonein northwest iowaproject period: 02 18 2026 through 02 17 2029THE purpose of this award is to refine the…

The U.S. Geological Survey awarded a $330,000 Cooperative Agreement to the University of Iowa on February 18, 2026, for geochemical and geochronological mapping of the Western Spirit Lake Tectonic Zone in northwest Iowa, funded under the Earth Mapping Resources Initiative (CFDA 15.073).

The recipient will refine understanding of the timing of emplacement and formation of critical mineral systems along the Western Spirit Lake Tectonic Zone by compiling and evaluating existing geologic data, drafting new rock core logs, and analyzing selected rock core sections with a portable X-ray fluorescent spectrometer to identify horizons with elevated phosphorus, potassium, uranium, and zirconium indicating potentially datable minerals such as zircon, apatite, monazite, titanite, and baddeleyite. The University of Iowa will prepare petrographic thin sections from intervals with new or existing geochemical and geochronological data for mineral phase and elemental mapping at the university's Materials Analysis, Testing, and Fabrication facility. Additional samples will be sent to USGS laboratories for whole rock geochemical analyses, and suitable horizons will undergo isotopic dating and trace element geochemistry analysis at the USGS Geology, Geophysics, and Geochemistry Center in Denver, Colorado, with grain samples analyzed for uranium-thorium-lead trace elements. These activities leverage airborne geophysical data acquired by USGS in 2024 and support mineral potential assessment and future geologic mapping. The award period runs from February 18, 2026, through February 17, 2029, with place of performance in Iowa.

Geochemical and geochronological mapping of the western spirit lake tectonic zonein northwest iowaproject period: 02 18 2026 through 02 17 2029THE purpose of this award is to refine the understanding of the timing of emplacement and formation ofcritical mineral systems along the western spirit lake tectonic zone (wsltz) in northwest iowa. Mineralresources occur throughout the superior province and the likelihood of unrecognized deposits in northwestiowa warrant further investigation. The quantitative analyses and mineral potential study proposed hereensure the maximum utilization of new airborne geophysical data acquired by U.S. Geological survey(USGS) in 2024. New geochronological data will support geologic mapping as well as enableinterpretations within and outside the area of interest (AOI). Geochemical analyses combined withpetrographic studies will support this mineral potential assessment and future geologic mapping.following a compilation and an evaluation of existing data within the AOI, project personnel will draft newrock core logs and analyze selected sections of rock cores with a portable x-RAY fluorescent (pxrf)spectrometer to locate horizons with elevated p, k, u, and ZR, indicating the presence of potentially datableminerals (e.g., zircon, apatite, monazite, titanite, baddeleyite). Petrographic thin sections will be made fromintervals with new or existing geochemical and or geochronological data for mineral phase and elementalmapping at the university of iowa materials analysis, testing, and fabrication (matfab) facility, andadditional samples will be sent to u.s geological survey (USGS) labs for further whole rock geochemicalanalyses. Suitable horizons for isotopic dating and trace element geochemistry analysis will be run at theusgs geology, geophysics, and geochemistry center (gggsc) in denver, colorado. These samples willfirst be processed and prepared at the university of iowa. Grains will be analyzed for u-TH-PB traceelements with a single-collector inductively coupled plasma mass spectrometry (ICP-MS). Data reductionand spot guidance by CL BSE PPL images will target the concordant points for the LU-HF analysis on amulti-collector ICP-MS. Furthermore, five critical samples will be analyzed for high-precision agedeterminations via chemical abrasion isotope dilution thermal ionization mass spectrometry, preformed atthe boise state isotope geology lab.at the end of the three-year cooperative agreement period, this project will result in the generation of newrock core descriptions integrated with petrographic, geochemical, and geochronologic data. A finaltechnical report will include a framework for mineral deposit genetic models with inferred tectonic andmagmatic processes (following ORE deposit types defined by the USGS), a mineral potential analysisincluding GIS coverages of mineral occurrence extent and relative enrichment, sampling methodologies, analytical data and results, and interpretations. The report will be made available to the public. In order to relieve dependence on foreign sources of critical minerals, geoscientists must conduct thefoundational research needed to identify domestic resources. This project will generate a wealth of newdata and interpretations that will benefit future academic research and exploratory investigations of criticalmineral resources of concealed precambrian basement rocks in the upper midcontinent region.