14 Traditional and Innovative Methods of Interpreting Sedimentary Environments: Examples from the Appalachian Basin (Posters)

Thursday, 20 March 2025
1:00 PM - 5:00 PM
Shenandoah ABC

TRADITIONAL AND INNOVATIVE OUTCROP ANALYSIS IN THE APPALACHIAN BASIN

Paper number: 14-2
Program: Theme Sessions
Time: 1:00 PM – 5:00 PM

Authors

Abstract

The Ordovician Juniata Formation is exposed as a roadcut along US Route 322 in Potters Mills, Pennsylvania. Interpretations of the depositional environment here have historically varied from fluvial to shallow marine with more recent interpretations suggesting it represents a transition from shallow marine to fluvial setting. Recent road construction has exposed fresh surfaces along the existing roadcut and provide an opportunity for a renewed perspective on the depositional environments expressed in this exposure. Bedding is inclined at the northern and southern fringes of the exposure and allows easy access for stratigraphic description. However, as bedding flattens in the central portion of the exposure, across the axis of a second-order syncline, access to the youngest strata in this exposure becomes impossible. Within this vertical section, there are repeated packages of fining-upward successions, where closer inspection is needed to assess the environment of deposition. We address this accessibility problem with the use of a Mavic 2 Enterprise Advance unmanned aerial vehicle (UAV) equipped with a high-resolution camera system capable of capturing 48 megapixel color images with an additional 640x512 thermal resolution camera with ±2 °C accuracy. These photographs allow for qualitative description of features including stratal surfaces and sedimentary structures, including evidence of cross bedding, trace fossils, and soft-sediment deformation. In areas where vegetation obscured bedding, thermal imaging was employed to help differentiate between different bedding surfaces. The outcrop faces south, south-east and was being warmed by the sun as the outcrop was flown in the early morning. Additionally, beds can be counted and their thicknesses measured in order to perform quantitative stacking pattern analysis, which provides insight into base level trends at the time of deposition. This ultimately aids in discerning a terrestrial from a marginal marine depositional setting. Utilizing the UAV allows us to obtain both quantitative and qualitative information that would otherwise remain tantalizingly just out of reach for study.

Geological Society of America Abstracts with Programs. Vol. 57, No. 2

doi: 10.1130/abs/2025SE-408664

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