Acid Generation Potential in Sevier Shale Roadcuts: Weathering Stages and Acidity Evolution

Abstract

This study investigates the relationship between field-observable characteristics and geochemical properties of the Ordovician-aged Sevier Shale to develop practical guidelines for roadside reclamation. When left non-vegetated after excavation, Sevier Shale frequently causes erosion, acid drainage, and water quality degradation. Samples collected from various weathering stages across Northeast Tennessee were analyzed for visual indicators (color, texture), field reactions (HCl, H₂O₂), and laboratory parameters (pH, electrical conductivity). Previous research suggested that the results should reveal significant correlations between weathering intensity, indicated by color changes from dark gray/blue to yellowish-brown, and geochemical properties, including acidity and salinity. The transformation from pyrite-rich fresh shale to oxidized material generates sulfuric acid while producing gypsum, creating complex mineral transformations that influence vegetation establishment or lack thereof. This research results should provide reclamation needs with field-applicable methods to identify problematic shale material, allowing for targeted treatment strategies during roadcut stabilization and reclamation projects which can also be confirmed with laboratory results. The findings should establish a practical assessment framework to improve the long-term management of disturbed Sevier Shale sites throughout the Appalachian region.

Start Time

16-4-2025 9:00 AM

End Time

16-4-2025 10:00 AM

Room Number

272

Presentation Type

Oral Presentation

Presentation Subtype

Research-in-Progress

Presentation Category

Science, Technology and Engineering

Faculty Mentor

Daniel Johnson

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Apr 16th, 9:00 AM Apr 16th, 10:00 AM

Acid Generation Potential in Sevier Shale Roadcuts: Weathering Stages and Acidity Evolution

272

This study investigates the relationship between field-observable characteristics and geochemical properties of the Ordovician-aged Sevier Shale to develop practical guidelines for roadside reclamation. When left non-vegetated after excavation, Sevier Shale frequently causes erosion, acid drainage, and water quality degradation. Samples collected from various weathering stages across Northeast Tennessee were analyzed for visual indicators (color, texture), field reactions (HCl, H₂O₂), and laboratory parameters (pH, electrical conductivity). Previous research suggested that the results should reveal significant correlations between weathering intensity, indicated by color changes from dark gray/blue to yellowish-brown, and geochemical properties, including acidity and salinity. The transformation from pyrite-rich fresh shale to oxidized material generates sulfuric acid while producing gypsum, creating complex mineral transformations that influence vegetation establishment or lack thereof. This research results should provide reclamation needs with field-applicable methods to identify problematic shale material, allowing for targeted treatment strategies during roadcut stabilization and reclamation projects which can also be confirmed with laboratory results. The findings should establish a practical assessment framework to improve the long-term management of disturbed Sevier Shale sites throughout the Appalachian region.