Geologic Map Database of the Washington DC Area Featuring Data From Three 30 X 60 Minute Quadrangles: Frederick, Washington West, and Fredericksburg

Online link https://geo-nsdi.er.usgs.gov/metadata/open-file/01-227/metadata.faq.html
Description The Washington DC Area geologic map database (DCDB) provides geologic map information of areas to the NW, W, and SW of Washington, DC to various professionals and private citizens who have uses for geologic data. Digital, geographically referenced, geolo
Originators Davis, Adam M.; Southworth, C. Scott; Schindler, J. Stephen; and Reddy, James E.
Publication U.S. Geological Survey Open-File Report 01-227

Related topics

States or counties

Overview of attributes

>The following is a brief description of the data layers, tables, and their associated
>attributes that are used in this report.
>
>GEOLOGIC DATA:
>BEDROCK - Polygon data layer of bedrock geologic map units
>  BEDROCK.PAT items:
>    MAPUNIT - Bedrock geologic map unit code
>    COA_ID - Compound object archive identifier, map unit names and descriptions -
>             a data linkage hub in North American Data Model (NADM) 4.3
>
>FAULT - Line data layer of geologic faults and folds
>  FAULT.AAT items:
>    SYMBOL - Symbol number from FAULT.LIN or ALCNEW61.LIN linesets, used for plotting
>    SYMBOL-ARC - Symbol number from GDS1.LIN lineset, used for plotting
>    FEATURE - Geologic Data Systems (GDS) assigned feature description
>    ELEVATION - GDS assigned attribute
>    TYPE - Type of fault
>      TYPE Code  Description
>         AC      Anticline
>         AF      Antiform
>        ARO      Arrow showing movement along strike-slip fault
>         FZ      Fault zone
>          N      Normal fault
>         NT      Normal fault re-activated as thrust fault
>         OT      Overturned thrust fault
>         SC      Syncline
>         SF      Synform
>         SS      Strike-slip fault
>          T      Thrust fault
>         TA      Thermal aureole
>         UF      Unclassified fault
>        ULF      Unclassified linear feature
>    CODE - Identifies fault segments which are overlaid by surficial deposits
>           (CODE = 2).  Used for plotting.  Relevant only for those faults which
>           lie within the boundary of the USGS Frederick 1:100000-scale map.
>    QUAD - Identifies the USGS 1:100000-scale map to which the feature belongs
>      QUAD
>      Code  Description
>       FB - Fredericksburg
>       FK - Frederick
>       WW - Washington West
>
>NEAT - Line data layer of map neatline
>
>SINK - Point data layer of sinkhole locations
>  SINK.PAT items:
>    MAPUNIT - Set to 'Sinkhole'
>
>STRUCTURE - Point data layer of geologic structure
>  STRUCTURE.PAT items:
>    DIP - Dip value (planar data) or plunge value (linear data)
>    STRIKE_ANG - GDS assigned angle measured from North
>    AZIMUTH - Angle measured from North in right-hand rule (planar data).
>              Routines used to digitize the geologic structure symbols that
>              lie within the boundaries of the USGS Frederick and Washington
>              West 1:100000-scale maps (item QUAD equal to 'FK' and 'WW',
>              respectively) resulted in the azimuth value for those symbols to
>              be calculated based on a northern trend (270<=azimuth<=90).
>              Southern trending azimuth values (90<azimuth<270) for structure
>              symbols associated with the Frederick and Washington West maps
>              were translated to their northern trend equivalents.  If necessary,
>              the southern trending azimuth values for these symbols can be
>              restored using the item SYMB_ANG and the following equations:
>                For 180<SYMB_ANG<=270,
>                  azimuth = AZIMUTH + 180
>                For 270<SYMB_ANG<360,
>                  azimuth = AZIMUTH - 180
>    TYPE - Type of geologic structure.  Relevant for geologic structure data
>           that lies within the boundaries of the USGS Frederick and Washington West
>           1:100000-scale maps (item QUAD equal to 'FK' and 'WW')
>      TYPE Code  Description
>        AGE      Sample site for U-Pb isotopic technique for age date
>         HB      Horizontal bed
>        I1C      Inclined first-generation Paleozoic cleavage and (or) schistosity
>        I2C      Inclined second-generation Paleozoic cleavage and (or) schistosity
>        IEF      Inclined early foliation
>         IB      Inclined bed
>         IF      Inclined Middle Proterozoic foliation
>        IMP      Inclined mylonitic and phyllonitic foliations
>        IPF      Inclined phyllonitic foliation
>         MA      Minor antiform
>         OB      Overturned bed
>         QM      Quarry or mine
>        RAD      Greater than 200 pCi/L of soil gas radon
>        V1C      Vertical first-generation Paleozoic cleavage and (or) schistosity
>        V2C      Vertical second-generation Paleozoic cleavage and (or) schistosity
>         VB      Vertical bed
>        VEF      Vertical early foliation
>         VF      Vertical Middle Proterozoic foliation
>        VMP      Vertical mylonitic and phyllonitic foliations
>    SUB_TYPE - Type of quarry mine
>      SUB_TYPE
>        Code    Description
>         Ag     Silver
>         Au     Gold
>          C     Chromite
>         Cu     Copper
>          D     Diabase
>          F     Hematite, limonite, and iron-ore
>          L     Limestone
>          M     Marble
>         Mg     Magnetite
>         Mn     Manganese
>         Pb     Lead
>          S     Building stone
>         Sl     Slate
>         Zn     Zinc
>    SYMB_ANG - Standard Cartesian angle measured from East.  Used for plotting.
>    DIPDIR - Direction of dip (planar data) or trend (linear data) measured from North
>    SYMBOL - Symbol number from the LOUDOUN_AP.MRK markerset or the MPLY.LIN lineset,
>             used for plotting
>    FEATURE - Type of geologic structure.  Relevant for geologic structure data that
>              lies within the boundary of the USGS Fredericksburg 1:100000-scale
>              map (item QUAD equal to 'FB')
>    GROUP - GDS assigned attribute
>    METHOD - GDS assigned attribute
>    SOURCE - GDS assigned attribute
>    DIP_DIR - GDS assigned attribute
>    SYMB_ARC - Symbol number from the GDS1.MRK markerset, used for plotting
>    QUAD - Identifies the USGS 1:100000-scale map to which the structure data belongs
>      QUAD
>      Code  Description
>       FB - Fredericksburg
>       FK - Frederick
>       WW - Washington West
>
>SURFICIAL - - Polygon data layer of surficial geologic map units
>  SURFICIAL.PAT items:
>    MAPUNIT - Surficial geologic map unit code
>    COA_ID - Compound object archive identifier, map unit names and descriptions -
>             a data linkage hub in North American Data Model (NADM) 4.3
>
>BASE DATA:
>POLBND - Net data layer of state and county boundaries:
>  POLBND.AAT items:
>    POLBND-ID
>      TYPE - State or county boundary
>  POLBND.PAT items:
>    STATE_NAME - State in which county resides
>    CNTY_NAME - County name
>    STATE_FIPS - State FIPS code (character field)
>    CNTY_FIPS - County FIPS code (character field)
>    FIPS - FIPS code for state/county (character field)
>    MAJOR# - DLG code
>    MINOR# - DLG code
>      Major DLG  Minor DLG
>        Code       Code     Description
>         91        ---      State FIPS code (integer field)
>         92        ---      County FIPS code (integer field)
>
>ROADS - Line data layer of major highways
>  ROADS.AAT items:
>    MAJOR# - DLG code
>    MINOR# - DLG code
>      Major DLG  Minor DLG
>        Code       Code     Description
>        170        201      Primary route, class 1, undivided
>        170        203      Primary route, class 1, divided
>        170        204      Primary route, class 1, one way
>        170        205      Secondary route, class 2, undivided
>        170        207      Secondary route, class 2, divided
>        170        209      Road or street, class 3
>        170        210      Road or street, class 4
>        170        401      Traffic circle
>        170        402      Cloverleaf or interchange
>        170        607      Underpassing
>        170        617      Business route
>        172        ---      Interstate route number
>        173        ---      U.S. route number
>        174        ---      State route number
>
>TOPO - Line data layer of elevation contours
>  TOPO.AAT items:
>    MAJOR# - DLG code
>    MINOR# - DLG code
>      Major DLG  Minor DLG
>        Code       Code     Description
>         20        20O      Contour (index or intermediate)
>         20        201      Carrying contour
>         20        204      Amended contour
>         20        208      Closure line
>         20        611      Depression
>         24        ---      Elevation in whole meters
>    TYPE - Type of contour: index (Index) or intermediate (Inter),
>           used for plotting
>
>HYDRO - Polygon data layer of major water bodies
>  HYDRO.PAT items:
>    RINGS_OK - Attribute assigned by the Chesapeake Bay Program
>    RINGS_NOK - Attribute assigned by the Chesapeake Bay Program
>    FEATURE - Type of hydrologic feature (stream, pond, marsh, etc.)

http://pubs.usgs.gov/of/2001/of01-227/of01227.pdf