DCNR - Surface Topography Beneath the Newark-Gettysburg Basin, Pennsylvania [Pennsylvania]
Pennsylvania Spatial Data Access (PASDA) · 2025 Full Details
Full Details
- Title
- DCNR - Surface Topography Beneath the Newark-Gettysburg Basin, Pennsylvania [Pennsylvania]
- Description
- PaGS created a new subsurface geologic dataset based on existing borehole data, a re-interpreted seismic reflection profile, and previously published non-digital products through digitization of cross section traces and extraction of XYZ data from cross sections. The generated digital surface represents the base of the Mesozoic consolidated rock units within the Newark-Gettysburg basin. PaGS and Harrisburg University of Science and Technology (HUS&T) georeferenced and digitized 66 interpretive geologic cross sections that cross the boundary of the Newark-Gettysburg basin. The cross sections were retrieved from 22 publications by various authors from PaGS and USGS dated between 1931 to 2025. The cross sections were digitized into polylines and subsequently georeferenced by first georeferencing the scanned versions of the source maps, matching the start and end of each cross section to its corresponding transect line on the map (horizontal georeference), and then by performing a transformation calculation to assign Z values to the endpoints of the digitized cross section (vertical georeference). The polylines were then converted into points with XYZ coordinates. Each point from the digitized cross sections was attributed with publication source information and contact type (e.g., unconformity, fault, etc.). Arm Group, LLC provided a dataset of XYZ locations of the data shots and the elevations of the interpreted base of the Gettysburg basin from a reprocessed seismic reflection dataset originally collected in 1974 across the Gettysburg basin (Transect Line 1410-P-4). PaGS prepared a 3D model surface of the base of the Newark-Gettysburg basin in ESRI ArcPro version 3.1.4 by combining the point data from the 66 interpretive geologic cross sections, 2 available borehole logs, and 1 seismic reflection profile. For geologic cross sections not interpreted to bottom of the basin, the interpreted unconformity beneath the Triassic sedimentary units in each geologic cross section was extended in a linear fashion to ?20,000 feet or to a depth corresponding to a similar extension on the opposing side of the basin. Contour lines at 1,000-foot intervals were constructed in a 3D space between the interpreted geologic cross sections, extrapolated unconformity lines, and the interpreted seismic reflection data to create a model "scaffolding". Two borehole logs were available to constrain the contour placement; one borehole extended below the unconformity and is the sole empirical subsurface input point for the model. A total of 8,169 points (surface and subsurface) were used as inputs for this modeling effort. Four tiered natural neighbor interpolations at varying grid cell sizes were performed using the constructed contour lines as inputs: "Tier 1" represents the confidence in the empirical data used in the project with a grid cell size of 40 feet; "Tier 2" represents the confidence in the interpreted data and resolution of the surficial geologic mapping with a grid cell size of 400 feet; "Tier 3" represents the confidence in the model space between the interpreted data points with a grid cell size of 800 feet; and "Tier 4" represents the confidence in the extrapolated data and model space between extrapolated data points with a grid cell size of 1,600 feet. Data points were extracted from each raster with the corresponding Z values of each cell attributed to the points. The resulting modeled surface is a point dataset with varying horizontal grids and was constructing by merging: Tier 1 points within 400 feet of the borehole data; Tier 2 points within 4,000 feet of the surficial border of Mesozoic formations and within 4,000 feet of the interpretive geologic cross sections or seismic transect; Tier 3 points within 8,000 feet of the contour lines directly connecting the geologic cross sections and seismic transect; and Tier 4 points located outside of the Tiers 1, 2, and 3 buffer zones.
- Creator
- Pennsylvania Department of Conservation and Natural Resources
- Publisher
- Pennsylvania Spatial Data Access (PASDA)
- Date Issued
- 2025
- Access Rights
- Public
- Format
- File
- Language
- English
- Date Added
- November 16, 2025
- Provenance Statement
- The metadata for this resource was last retrieved from PASDA on 2025-11-16.
Location
Links
Cite and Reference
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Citation
Pennsylvania Department of Conservation and Natural Resources (2025). DCNR - Surface Topography Beneath the Newark-Gettysburg Basin, Pennsylvania [Pennsylvania]. Pennsylvania Spatial Data Access (PASDA). https://www.pasda.psu.edu/uci/DataSummary.aspx?dataset=2253 (dataset) -
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