253-7 Conodont Biostratigraphy and Taxonomy of the Type Mercer Limestone

Session: Conodonts from North America and Beyond - Honoring the Career of Dr. James E. Barrick

Presenting Author:

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Abstract:

The Pennsylvanian stratigraphy in the Appalachian basin comprises hundreds of localized lithostratigraphic units. This has resulted in the development of several stratigraphic frameworks that vary across state and physiogeographic boundaries. The spatial and temporal relationships between specific beds, members, or depositional sequences is not always clear, making regional correlations difficult. Because of this, only a few regionally mappable units are recognized despite the abundance of named lithostratigraphic units, making it difficult to characterize any specific rock or natural resource within these broadly defined intervals. Relating the broadly defined regionally mapped units with the finely subdivided local stratigraphies is a significant challenge. The “Mercer Formation” is an informally recognized interval in the upper part of the Pottsville Group consisting of clastic-dominated sequences of sand, silt, shale, coal, and limestone. The Upper Mercer and Lower Mercer limestones are considered regionally extensive marker beds in this interval, but their character and preservation is variable across the basin, making them difficult to recognize using lithology alone. Furthermore, only a single limestone is observed at the Mercer Limestone type locality, and it remains unclear whether the type limestone correlates to the Upper Mercer or Lower Mercer. Here we share preliminary results from our investigation of conodonts from the type Mercer Limestone locality in western Pennsylvania to determine its biostratigraphic properties and age. This is a necessary first step towards resolving the stratigraphy of the “Mercer Formation” and refining the Atokan-Desmoinesian conodont biostratigraphy in the basin. 

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

doi: 10.1130/abs/2025AM-8747

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