7 Geologic mapping in the digital age: products, workflows, and methodologies (Posters)

This session will highlight geologic maps and their derivatives, showcasing products that leverage innovative digital methods and workflows, novel application of remote sensing data, and integration of advanced data processing techniques.

Sunday, 22 March 2026
8:00 AM - 12:00 PM
CCC, Ballroom C

Building a 3D Geologic Framework from Mixed-Resolution Data: Digital Mapping of the Newark–Gettysburg Basin Subsurface

Paper number: 7-2
Program: Technical Sessions
Time: 8:00 AM – 8:00 AM

Authors

Abstract

Advances in digital geologic mapping increasingly enable the integration of legacy interpretations with modern datasets to produce new derivative products that extend the value of historic work. We present a digital workflow for constructing a three-dimensional geologic surface representing the base of Mesozoic consolidated rock units within the Newark–Gettysburg Basin of southeastern Pennsylvania, developed as part of an ongoing effort to build a statewide 3D geologic framework.

The modeled surface was generated using a combination of digitized interpretive geologic cross sections, limited borehole data, and a reprocessed seismic reflection profile. Sixty-six cross sections from 22 Pennsylvania Geological Survey (PaGS) and U.S. Geological Survey publications dating from 1931 to 2025 were georeferenced and digitized. A two-step georeferencing approach was applied, consisting of horizontal alignment of cross-section traces to mapped transects and vertical transformation to assign elevation values, allowing extraction of XYZ point data. These points were attributed with source metadata and interpretive features such as unconformities and faults. Additional subsurface constraints were provided by two borehole logs and a reinterpreted seismic reflection profile across the Gettysburg Basin.

Using ArcGIS Pro, more than 8,000 input points were combined to construct a 3D model surface. Where cross sections did not extend to the basin floor, unconformities were extrapolated to depth using geologically consistent assumptions. A contour-based “scaffolding” approach and tiered natural neighbor interpolations were employed to explicitly represent varying levels of data density, resolution, and interpretive confidence across the basin. The final product consists of nearly 97,000 points representing the modeled basin base at multiple spatial resolutions.

This work demonstrates a reproducible digital methodology for transforming non-digital geologic interpretations into modern 3D mapping products. The resulting dataset highlights the continued relevance of legacy geologic mapping when combined with contemporary GIS workflows and provides a foundation for future refinement using new mapping, seismic, and borehole data.

Geological Society of America Abstracts with Programs. Vol. 58, No. 2

doi: 10.1130/abs/2026NE-411165

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