Bedrock Geologic Map of Vermont

Metadata also available as - [Outline] - [XML]

Frequently anticipated questions:

What does this data set describe?

Title: Bedrock Geologic Map of Vermont
The bedrock geology was mapped to study the geologic and tectonic history of the State of Vermont. The digital data are intended for use by all government, academic, commercial, or other agencies in need of digital geologic map information.
Additional contributions to the map were made by Norman L. Hatch, Jr., Douglas W. Rankin, Barry L. Doolan, Jonathan Kim, Charlotte J. Mehrtens, John N. Aleinikoff, and J. Gregory McHone. Digital cartography in Adobe Illustrator by Linda Masonic. GIS by Walsh and Gale. Topographic base maps from U.S. Geological Survey 1:100,000 Albany, MA-NY-VT, 1989; Claremont, NH-VT, 1985; Glens Falls, NY-VT, 1989; Keene, MA-NH-VT, 1986; Rutland, NH-VT, 1985; Ticonderoga, NY-VT, 1989; Lake Champlain North, VT-NH, 1981; Lake Champlain South, VT-NY, 1981; Mount Mansfield, VT, 1986; Montpelier, VT, 1986; Groveton, NH-VT-ME, 1988; and Mount Washington, NH-VT-ME, 1989. Printed map base projection and 10,000-meter grid, zone 18, Universal Transverse Mercator, 1927 North American Datum (NAD). In the Geographic Information System (GIS) database, the printed map was reprojected to the State Plane Coordinate System currently in use in Vermont, 1983 NAD. The printed map is accompanied by a GIS database, large format color sheets in Adobe Portable Document Format (PDF), and a Readme.txt file.
  1. How should this data set be cited?

    Ratcliffe, Nicholas M. , Stanley, Rolfe S. , Gale, Marjorie H. , Thompson, Peter J. , and Walsh, Gregory J. , 2011, Bedrock Geologic Map of Vermont: Scientific Investigations Map 3184, U.S. Geological Survey, Reston, Virginia.

    Online Links:

    Ratcliffe, N.M., Stanley, R.S., Gale, M.H., Thompson, P.J., and Walsh, G.J., 2011, Bedrock geologic map of Vermont: U. S. Geological Survey Scientific Investigations Map 3184, scale 1:100,000, 3 sheets.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -73.519802
    East_Bounding_Coordinate: -71.444478
    North_Bounding_Coordinate: 45.018809
    South_Bounding_Coordinate: 42.718156

  3. What does it look like?

  4. Does the data set describe conditions during a particular time period?

    Beginning_Date: 1989
    Ending_Date: 2011
    Currentness_Reference: publication date

  5. What is the general form of this data set?

    Geospatial_Data_Presentation_Form: Map

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set. It contains the following vector data types (SDTS terminology):

      • Complete chain (32,125)

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: State Plane Coordinate System 1983
      SPCS_Zone_Identifier: 4400
      Scale_Factor_at_Central_Meridian: 0.999964
      Longitude_of_Central_Meridian: -72.500000
      Latitude_of_Projection_Origin: 42.500000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000100
      Ordinates (y-coordinates) are specified to the nearest 0.000100
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

  7. How does the data set describe geographic features?

    The geologic data layers in the GIS database of this report include, 1) CONTAX (contacts) - Polygon and arc data layers of bedrock geologic map units, contacts, and faults, including a polygon attribute table, 2) DIKES - Arc data layers of dikes, and 3) GEOCHRONO - Point data layer of U-Pb zircon geochronology sample locations.
    Entity_and_Attribute_Detail_Citation: <>

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)

  2. Who also contributed to the data set?

    Additional contributions to the map were made by Norman L. Hatch, Jr., Douglas W. Rankin, Barry L. Doolan, Jonathan Kim, Charlotte J. Mehrtens, John N. Aleinikoff, and J. Gregory McHone. Digital cartography in Adobe Illustrator by Linda Masonic (USGS). Geographic Information System (GIS) database by Walsh and Gale.

  3. To whom should users address questions about the data?

    U.S. Geological Survey
    Attn: Gregory J. Walsh
    P.O. Box 628
    Montpelier, Vermont 05601

    802-828-4528 (voice)
    802-828-4465 (FAX)

Why was the data set created?

The bedrock geology was last mapped at a statewide scale 50 years ago at a scale of 1:250,000 (Doll and others, 1961). The 1961 map was compiled from 1:62,500-scale or smaller maps. The current map was created to integrate more detailed (1:12,000- to 1:24,000-scale) modern mapping with the theory of plate tectonics to provide a framework for geologic, tectonic, economic, hydrogeologic, and environmental characterization of the bedrock of Vermont.

How was the data set created?

  1. From what previous works were the data drawn?

  2. How were the data generated, processed, and modified?

    Date: 2011 (process 1 of 1)
    The geology was compiled at 1:100,000-scale from source maps ranging from 1:12,000- to 1:250,00-scale. The line and polygon data were first drafted with pen and ink on stable-base mylar greenlines of the 1:100,000-scale topographic base maps. Mylar greenlines were scanned and auto-vectorized in Adobe Illustrator. Film positive separates of the published topographic base maps were scanned and mosaicked in Illustrator. Illustrator line work was converted to Autocad DXF vector files and imported to Arc/Info version 9.3. Point data were heads-up digitized. Attribute data were compiled in Excel and joined with the shapefiles in ArcMap. Line and polygon data were edited in Arc/Info and converted to shapefiles. In ArcMap, layer files were created from the shapefiles. In ArcToolbox, Google Earth KMZ files were created from the layer files. Cartography was done in Adobe Illustrator CS4.

    Person who carried out this activity:

    Gregory J. Walsh
    U.S. Geological Survey
    P.O. Box 628
    Montpelier, Vermont 05601

    802-828-4528 (voice)
    802-828-4465 (FAX)

    Hours_of_Service: 0900 to 1700 Eastern Standard Time
    Data sources produced in this process:
    • Ratcliffe and others (2011)

  3. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    All attributes digitized during the creation process were verified by displaying the lines and points in the database with respect to the USGS 30 x 60 minute topographic base map (1:100,000 scale), but no formal tests were performed.

  2. How accurate are the geographic locations?

    The data were delineated on USGS 30 x 60 minute topographic maps at 1:100,000 scale. The horizontal accuracy of solid lines and points is considered "approximate" and dotted lines are considered "concealed", according to the terminology set forth in the FGDC Digital Cartographic Standard for Geologic Map Symbolization (2006) <>

  3. How accurate are the heights or depths?

    The data were delineated on a USGS 30 x 60 minute topographic maps at 1:100,000 scale. Therefore, the vertical accuracy of the base map is assumed to be within National Map Accuracy Standards. Vertical accuracy of the geologic data was not tested.

  4. Where are the gaps in the data? What is missing?

    The geologic contacts were delineated on USGS 1:100,000-scale topographic base maps from published and unpublished observations. The features in the database are not based on legal parcels or definitions.

  5. How consistent are the relationships among the observations, including topology?

    These data are believed to be logically consistent, though no tests were performed. Geometry is topologically clean.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Although all data released in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Use_Constraints: none

  1. Who distributes the data set? (Distributor 1 of 1)

    U.S. Geological Survey - Information Services
    Box 25286, Denver Federal Center
    Denver, Colorado 80225

    1-888-ASK-USGS (voice)

    Hours_of_Service: 0900 to 1700 Mountain Standard Time
  2. What's the catalog number I need to order this data set?

    USGS Scientific Investigations Map 3184

  3. What legal disclaimers am I supposed to read?

    These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product or process disclosed in this report, and represents its use would not infringe privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data and related materials. Reference therein to any specific commercial product, process, or related service by trade name, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.

  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 08-Mar-2012
Metadata author:
Attn: Gregory J. Walsh
P.O. Box 628
Montpelier, Vermont 05601

802-828-4528 (voice)

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)

Generated by mp version 2.9.14 on Thu Mar 08 11:32:24 2012