64-4 Rare Earth Element (REE) Enrichment in Cretaceous Paleosols in Northwestern Iowa

Session: Emerging Voices in Soil and Paleosol Science (Posters)

Poster Booth No.: 127

Presenting Author:

Michelle Wikner

Authors:

Wikner, Michelle¹, Cramer, Bradley Douglas², Peate, David W.³, Meyer, Jessica R.⁴, Bancroft, Alyssa⁵, Tassier-Surine, Stephanie A.⁶, Smith, Rachel⁷

(1) University of Iowa - School of Earth, Environment, and Sustainability, Iowa City, IA, USA, (2) University of Iowa - School of Earth, Environment, and Sustainability, Iowa City, IA, USA, (3) University of Iowa - School of Earth, Environment, and Sustainability, Iowa City, IA, USA, (4) University of Iowa - School of Earth, Environment, and Sustainability, Iowa City, IA, USA, (5) Iowa Geological Survey - University of Iowa, Iowa City, IA, USA, (6) Iowa Geological Survey - University of Iowa, Iowa City, IA, USA, (7) Kansas Geological Survey - University of Kansas, Lawrence, KS, USA,

Abstract:

The Cretaceous strata preserved in northwestern Iowa begin with the Dakota Formation, which sits unconformably above Paleozoic carbonates of varying ages (Devonian-Pennsylvanian). A pronounced paleosol is identifiable at the base of the Cretaceous succession in the few drill cores that penetrate this interval, and additional paleosols are identified within the Nishnabotna and Woodbury members of the Dakota Formation. These paleosols are typically lateritic and deeply weathered with varying white or deep red intervals. As part of an ongoing NSF Established Program to Stimulate Competitive Research (EPSCoR) grant, these paleosols have become targets for investigation of Rare Earth Element (REE) resources.

 

After initial XRF core scanning of these units identified potential REE resources, bulk geochemistry of these intervals has been investigated using traditional open-vessel digestion ICP-MS geochemistry. The results demonstrate that some intervals of these paleosols contain greater than 8,000 ppm total REE and that they are particularly enriched with light REEs. The XRF core scanning served as an excellent prospecting tool for additional detailed geochemical research. Some, but not all, of the intervals of enriched REE were also visible in gamma ray logs of the cores. Ultimately, these intervals, some of which are greater than 30 feet thick, may prove to be significant future resources for REEs in the U.S. Midcontinent. The complete areal extent of these intervals and their REE distribution has not yet been fully evaluated and will require additional research in the future.

 

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-10656

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