NEW DIGITAL SURFICIAL GEOLOGIC MAP COMPILATION OF MASSACHUSETTS

The U.S. Geological Survey, in cooperation with the Commonwealth of Massachusetts Office of the State Geologist and Executive Office of Energy and Environmental Affairs, is engaged in a comprehensive effort to produce a statewide digital surficial geologic map at a 1:24,000-scale level of accuracy. The new map products revise previous digital surficial geology layers (MassGIS, 1999) that were compiled on base maps at regional scales of 1:125,000 and 1:250,000. The purpose of this project is to provide fundamental geologic data for the evaluation of natural resources, hazards, and land information within the Commonwealth of Massachusetts. The surficial geology of the state is being compiled and published in ten regional sections (available online at http://pubs.usgs.gov/of/2006/1260); sections A through E in eastern Massachusetts have been published and the remaining sections are targeted for completion by 2010.

The geologic map files represent simplified lithic materials units in ArcGIS shapefiles, in which map units are arranged in a series of layers according to superposition. Visualize the till and bedrock outcrops as the bottom layer. The succeeding layer shows the continuous extent of coarse- and fine-grained stratified meltwater deposits. Postglacial map units, such as floodplain alluvium and swamp deposits, overlie the older materials and are included in the top layer. The availability of a continuous digital data layer of the complete distribution of glacial meltwater deposits allows for increased capabilities for ground-water and surface-water modeling, as well as sand and gravel resource volume calculations.

The map products also include descriptive text, .pdf format files for printing individual quadrangles, 1:24,000 scale topographic base maps (raster), an ArcGIS map document (.mxd), and FGDC-compliant metadata for all layers.