DIGITAL PRESERVATION OF PALEOZOIC ROCKS AND NEW METHODS FOR ANALYSIS, PRESERVATION, AND FUTURE REINTERPRETATION OF SEDIMENTARY ENVIRONMENTS

Many key stratigraphic type sections within the Central and Northern Appalachians were first documented approximately a century ago. These type sections serve as the basis for the interpretation of sedimentary environments and the stratigraphic framework throughout the region. Significant outcrop degradation over the last century has left many l type sections unrecognizable or inaccessible, limiting the ability to use these type sections to reconcile stratigraphic inconsistencies. The loss of these critical data impacts a wide range of geologists and presents challenges to the ongoing efforts in the larger geologic mapping community.

Structure from Motion (SfM) photogrammetry of outcrops facilitates preservation of historic type sections and compliments measured section descriptions when new reference sections are established. SfM allows the preservation of key outcrops in their current state through high-resolution 3D models. These models provide the means to visualize and inspect stratigraphic sections from unique perspectives, and the data can be readily exported to point clouds and used to make orthomosaics. These data facilitate detailed outcrop mapping including the collection of quantitative data that can be integrated with geospatial mapping software.

We present new 3D outcrop data from Middle Silurian and middle Upper Devonian strata of the Central and North-Central Appalachian Basin. Middle Silurian sites include key intervals from the McKenzie Formation and Williamsport Sandstone. Sites from the middle Upper Devonian strata include the Brallier and Foreknobs Formations and their stratigraphic equivalents, the Lock Haven Formation, and the Irish Valley Member of the Catskill Formation. Models were collected with both ground- and aerial-based methods and demonstrate an accessible and viable means to produce reliable digital representations of important historic exposures. Additionally, we will demonstrate how these digital data are used both to record new reference sections that redefine the Brallier/Foreknobs interval in the central portion of the Appalachian Basin and to investigate their along-strike variability moving north.