14-4 Evaluating Critical Mineral Potential in Pennsylvania’s Marcellus Shale

Session: Linking Mineral Resources and the Geologic Framework of North America: The USGS Earth Mapping Resources Initiative (Earth MRI) and Related Activities

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The growing demand for rare earth elements (REEs) has underscored the need for domestic sources, as China currently dominates global REE supply. The exploration of domestic shale deposits, including the Marcellus Shale within Pennsylvania, has garnered increasing attention. This study investigates the geochemical trends of REEs and critical mineral distribution in the Marcellus Shale, with a focus on the relationship between REEs and selected elements with depositional conditions and the potential for REE extraction.

Preliminary findings indicate a relative enrichment in LREEs compared to HREEs, alongside a depletion of Mn and Co and elevated concentrations of elements such as Ba, Cd, Mo, V, U, and Zn. These trends may reflect depositional environments that were potentially anoxic or euxinic, influenced by both biological and physical factors. The Ce anomaly is used as an indicator for deoxygenation, and values from our samples align with low oxygen thresholds observed at other sites. We are exploring whether the sediment burial rate and its potential role in organic matter preservation contribute to the observed geochemical patterns.

While previous studies have explored REE extraction from shale deposits, methods applied to Marcellus Shale samples have demonstrated limited extraction efficiency, particularly for LREEs. These results suggest that REE extraction from black shales is a complex process, and a more detailed examination of black shale geochemistry may aid in identifying regions of the Marcellus Shale with enriched REE concentrations. Further research into the geochemical conditions driving these enrichments and optimizing extraction methods will be essential for evaluating the viability of these deposits as a potential REE source.

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

doi: 10.1130/abs/2025AM-11051

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