PROGRESS TOWARDS A COMPILATION OF SURFICIAL MAP UNITS IN THE DELAWARE RIVER BASIN

The U.S. Geoframework initiative of the U.S. Geological Survey is tasked with constructing seamless geologic maps from existing datasets across the country. As part of this effort, we are working to compile and generalize disparate geologic maps in the Delaware River Basin. In doing so, we have created a generalized classification strategy of surficial map units to reconcile differences across state lines. This strategy consists of (1) compiling already generalized datasets (e.g., New York at 1:250,000 scale) and converting them to a Geologic Map Schema (GeMS) geodatabase format with extended attributes, (2) compiling more detailed datasets (e.g., New Jersey at 1:100,000 scale and parts of Pennsylvania at 1;100,00 and 1:24,000 scale) of surficial map units into more generalized map unit names, and (3) joining these revised and consistent datasets. Here, we present the first step of this strategy in the context of New York State. Five digitized 1:250,000 scale map sheets were retrieved from the New York State Museum webpage and imported into a GIS software that was used to edit and compile map units and their descriptions. Manual techniques and automated GIS routines were used to check and correct errors in the original geospatial data using the original published maps for reference. Map unit descriptions were first compiled into a spreadsheet to construct a relational table containing descriptions for each map unit in GIS. The resultant product is a GeMS-compliant geodatabase for New York state that will be incorporated into a common database of the US Geoframework surficial geology compilation. Presently, we are working to compile additional datasets in New Jersey and the eastern and northeastern regions of Pennsylvania as part of the second step listed above. These compilations draw from existing 1:100,000 and 1:24,000 scale surficial geologic maps, which are being generalized to be consistent with the broader geologic descriptions of the New York geologic dataset. Taken together, these compilations represent a significant step toward a unified geologic framework for the Delaware River Basin at 1:250,000 scale and provide a conceptual workflow for compilation and generalization in other regions.