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Point dataset representing the topography of the surface beneath the Newark-Gettysburg basin in southeast Pennsylvania prepared at an intended-use scale of 1:250,000. The dataset is to be used as a predictor of the bottom of the Newark-Gettysburg basin for mapping, modeling, and/or decision making. Elevations presented as Z values in the point files are relative to the North American Vertical Datum of 1988 (NAVD88) in feet. The point density in the dataset corresponds to the confidence in the modeled surface; areas with a higher point density communicate a greater confidence in the elevations modeled at those locations.
The geodatabase (DR25-02_Mesozoic3D.gdb) contains two points feature classes: 1) InputPoints, which includes data points use to construction the model, and 2) ModeledSurfacePoints, which represents the modeled base of the Newark-Gettysburg basin. |
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Point dataset representing the topography of the surface beneath the Newark-Gettysburg basin in southeast Pennsylvania prepared at an intended-use scale of 1:250,000. The dataset is to be used as a predictor of the bottom of the Newark-Gettysburg basin for mapping, modeling, and/or decision making. Elevations presented as Z values in the point files are relative to the North American Vertical Datum of 1988 (NAVD88) in feet. The point density in the dataset corresponds to the confidence in the modeled surface; areas with a higher point density communicate a greater confidence in the elevations modeled at those locations.
The geodatabase (DR25-02_Mesozoic3D.gdb) contains two points feature classes: 1) InputPoints, which includes data points use to construction the model, and 2) ModeledSurfacePoints, which represents the modeled base of the Newark-Gettysburg basin. |
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Author Contributions: Elizabeth M. Cushman – model construction; geospatial analysis; geospatial data preparation. Morgen C. Baker – geospatial analysis; geospatial data preparation. Craig M. Ebersole – model construction; geospatial analysis; geospatial data preparation. Alfred C. Guiseppe – seismic reflection data interpretation; model construction; geospatial data analysis. Acknowledgements: HUS&T conducted digitization and georeferencing of source data for the model input. Arm Group, LLC acquired, reprocessed, and provided an interpretation of the seismic reflection profile. Ellen R. Fehrs of PaGS assisted with preparation and attribution of the digitized cross section points. Christopher W. Oest of PaGS provided thoughtful insight to morphology of the Newark-Gettysburg basin that helped the authors conceptually form the final topography of the modeled surface. |
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<DIV STYLE="text-align:Left;"><DIV><P><SPAN>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&amp;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.</SPAN></P></DIV></DIV> |
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<DIV STYLE="text-align:Left;"><DIV><P><SPAN>The data for the geologic units and structures contained in the geodatabase may be used provided that credit for the original (unaltered) data is given to the Pennsylvania Bureau of Geological Survey, Department of Conservation and Natural Resources. Users shall clearly indicate the source of the data. Users who modify the data in any way are obligated to describe the types of modifications they have made. Users are not to misrepresent these Pennsylvania Bureau of Geological Survey (or PaGS) data, nor to imply that changes they (users) have made were approved by the PaGS.These data are public information and, as such, the data may be used as a reference source and may be interpreted by organizations, agencies, units of government, or others based on needs; however, each user is responsible for the appropriate application of the data. Federal, state, or local regulatory bodies are not to reassign to PaGS any authority for the decisions they make using these data.The data are not meant for site-specific analysis at scales finer (i.e., larger, more detailed) than 1:250,000. Users are not to misrepresent the data by presenting any at scales for which it is not intended, nor to imply that presentation at such scales is approved by the PaGS.Not for commercial resale.Distribution LiabilityThese data files and accompanying documentation are provided "as is," and the user assumes the entire risk as to their quality and performance.The Commonwealth of Pennsylvania makes no guarantee or warranty concerning the accuracy of information contained in the geographic data or accompanying documentation. The Commonwealth of Pennsylvania further makes no warranties, either expressed or implied, as to any other matter whatsoever, including, without limitation, the completeness or condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user.Although these data have been processed successfully on a computer system at the Department of Conservation and Natural Resources, the Commonwealth of Pennsylvania makes no warranty, expressed or implied, regarding the use of the data files or accompanying documentation on any other computer system, nor does the act of distribution constitute any such warranty.Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the Commonwealth of Pennsylvania government or any agency thereof.The user shall save the Commonwealth of Pennsylvania harmless and indemnify it from any suits, claims, or actions arising out of the use of or any defect in the data files or accompanying documentation. The Commonwealth of Pennsylvania assumes no legal liability for the accuracy, completeness, or usefulness of the data files and accompanying documentation. In no event shall the Commonwealth of Pennsylvania have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data.</SPAN></P></DIV></DIV> |
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Surface Topography Beneath the Newark-Gettysburg Basin, Pennsylvania |
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["DEM","Geology","Pennsylvania","Mesozoic Basin","Pennsylvania Geological Survey","PAGS","DCNR","Department of Conservation and Natural Resources","elevation","environment","geoscientificInformation"] |
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en-US |
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150000000 |
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