Line, grid, and vector data, and maps for the airborne geophysical survey of the Moran Survey Area, Melozitna and Tanana quadrangles, central Alaska

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What does this data set describe?

Title:
Line, grid, and vector data, and maps for the airborne geophysical survey of the Moran Survey Area, Melozitna and Tanana quadrangles, central Alaska
Abstract:
This digital publication, GPR 2010-1, contains data produced from airborne geophysical surveys conducted in 2009 for the Moran survey area in the south-central Melozitna mining district, Melozitna and Tanana quadrangles, central Alaska. Aeromagnetic, electromagnetic (EM), and radiometric data were acquired by helicopter for about 653 sq miles. Fugro Airborne Survey's frequency-domain DIGHEM V system was used for the EM data. GPR 2010-1 includes (1) raw and processed linedata; (2) gridded, Google Earth, and Geotiff formats of the calculated linedata; (3) maps of the data; and (4) vector files of data contours and flight lines.
Supplemental_Information:
The airborne data were acquired and processed under contract between the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), and Stevens Exploration Management Corp. Fugro Airborne Surveys, the subcontractor, acquired and processed the data in 2009. A future publication will include the technical project report, interpretation map, and EM anomalies, as well as other files.

File 'gpr2010-001_readme.PDF' contains location figures, a table indicating which formats are available for each data type and associated map numbers, and much general information. File 'gpr2010-001_readme.PDF' also contains more complete information than this metadata for the supplemental information and completeness of data. Some detailed information about the data is given in the 'Entity_and_Attribute_Information' section of this metadata file. 'Moran-linedata.txt' gives information on the linedata in an easy-to-read format. All data are provided in NAD27, UTM zone 5N, except for Google Earth KMZ files, which are in Geographic Coordinate System (Simple Cylindrical projection) with a WGS84 datum. Besides NAD27, UTM zone 5N x and y coordinates, the linedata files also include latitude and longitude (Geographic Coordinate System with a WGS84 datum).

This publication, GPR2010-1, contains the following data types or files: LINEDATA (Geosoft binary GDB and Geosoft ASCII XYZ format), GRIDS, GEOTIFFS, GOOGLE EARTH FILES, VECTORS, and MAPS (PDF and HPGL/2 formats).

  1. How should this data set be cited?

    Burns, L.E., Fugro Airborne Surveys Corp., and Stevens Exploration Management Corp., 2010, Line, grid, and vector data, and maps for the airborne geophysical survey of the Moran Survey Area, Melozitna and Tanana quadrangles, central Alaska: Geophysical Report GPR 2010-1, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 DVD

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -153.90
    East_Bounding_Coordinate: -152.59
    North_Bounding_Coordinate: 65.47
    South_Bounding_Coordinate: 65.15

  3. What does it look like?

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

    Beginning_Date: Aug-2009
    Ending_Date: Feb-2010
    Currentness_Reference: publication date

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

    Geospatial_Data_Presentation_Form:
    raster digital data, tabular digital data, and vector digital data

  6. How does the data set represent geographic features?

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

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

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 5
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -153
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0

      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 25
      Ordinates (y-coordinates) are specified to the nearest 25
      Planar coordinates are specified in meters

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?

    Entity_and_Attribute_Overview:
    The linedata were divided into two separate database files for easier downloading. Both files, 'Moran_EM' and 'Moran_RAD', contain the same line numbers, fids, and locational data so that the files can be easily merged if wanted by the user. 'Moran_EM' contains magnetic and electromagnetic data, and 'Moran_RAD', the radiometric data. Both of these files are provided in Geosoft binary format (GRD) and in Geosoft ASCII XYZ format (XYZ). A text file ('Moran_Linedata.txt') contains some of the linedata information included in this metadata document, but in normal ASCII text format. Moran_Linedata.txt is included with each downloadable zip file.

    Each linedata file contains raw and processed linedata, and related calculated fields. Missing data are represented with the dummy variable '*'. Each of the 173 flight lines or partial flight lines (e.g. Line 10371, referred to as 'LINE' attribute) is associated with a 'DATE' (e.g. 2009/08/18), a 'FLIGHT (number)' (e.g. 29009), and a particular multi-record set of data. Each record represents data acquisition from one spatial location in the flight line. A total of 1,485,841 records are present in each data file.

    Entity_and_Attribute_Detail_Citation:
    L.E. Burns, Division of Geological & Geophysical Surveys and Fugro Airborne Surveys
    Moran_EM.GDB and Moran_EM.XYZ
    The file 'Moran_EM' contains raw and processed linedata and related calculated fields for locational, magnetic, and electromagnetic data. The file is provided in Geosoft binary grid (GRD) and Geosoft ASCII XYZ (XYZ) formats. Except for the 'LINE' attribute, all attributes, including 'DATE' and 'FLIGHT', are represented by one of the 49 data columns on each record. The 'LINE' and 'FLIGHT' attributes are discussed further in the attribute 'ID Cell'. (Source: L.E. Burns & Fugro Airborne Surveys)

    ID_CELL
    The 'ID CELL' occurs in the GDB file only; the contents of the 'ID CELL' are also present in the XYZ file. In the 'ID CELL' for this project, the 'LINE' attribute is followed by a colon followed by the 'FLIGHT' attribute, e.g. 'L10010:29010' and 'T19010:29017'. More than one line is typically flown on a particular date and flight; more than one flight may be flown on a particular date. Each ID-cell value will have an associated spreadsheet view consisting of a column for each of the 49 attributes. In the XYZ file, the 'LINE' and 'FLIGHT' attributes and the 'DATE' are present as header lines, one attribute per line, before each set of associated data, e.g.

      //Flight 29010
      //Date 2009/08/12
      Line 10010  (or 'Tie 10950', etc.)
      Followed by all records for points sampled along Line 10010.
         (Pattern is repeated for each line number).
    
    The 'ID CELL' content, particularly combined with the definitions below for this particular survey, provides information about the flight line layout. (Source: L.E. Burns & Fugro Airborne Surveys)

    Definitions of the 'LINE' and 'FLIGHT' attributes are listed below.

     LINE TYPES and SYMBOLS:
     Traverse lines – oriented nominally N-S (0 degrees);
     Tie lines      - oriented nominally E-W (90 degrees); and
     Border lines   - present inside and parallel the survey
                      tract border where traverse or tie lines
                      are not parallel to the border.
     Traverse lines – 'L' (GDB file); 'LINE' (XYZ file).
     Tie and border lines - 'T' (GDB file); 'TIE' (XYZ file).
     LINE NUMBERS
     In general, the traverse lines increase by 10 from west to
     east; the tie lines increase by 10 from north to south; and
     the border lines increase by 10 starting for this project
     in the south-central edge of the survey area and continuing in
     a clockwise direction until reaching the southeastern part.
    
     When more than one uninterrupted flight segment was needed
     to complete a planned flight line, the fifth digit is
     increased by '1' for each new flight version.
     MAIN LINE NUMBERS:
        Lowest Traverse Lines: L10010 (west)
        Highest Traverse Lines: L11520 (east)
        Lowest Tie Lines: T19010 (north)
        Highest Tie Lines: T19080 (south)
        Lowest Border Lines: T19090 (south-central, progressing)
        in clockwise direction)
        Highest Border Lines: T19130 (southeast)
    ------------------------------------------------------------
     'FLIGHT' DESIGNATORS
     The 5 digit flight designator consists of a two digit Fugro
     Dighem V system number (29 for this project) and a three
     digit flight identification number, e.g. '008'.
    

    X_NAD27z5N
    easting NAD27 (UTM Zone 5N) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:458130.23
    Maximum:519205.96
    Units:m

    Y_NAD27z5N
    northing NAD27 (UTM Zone 5N) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:7225239.02
    Maximum:7260818.41
    Units:m

    FID
    Fiducial increment; the time in tenths of seconds from the start to the end of the particular flight. Sampling typically occurred at each fiducial for almost all items in the database. (Source: Fugro Airborne Surveys)

    The attribute measurement resolution is 0.1 second. The values increase from the beginning of a flight to the end. Only FIDs during production flights are included in the database.

    LAT_WGS84
    latitude WGS84 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:65.1520411
    Maximum:65.4713032
    Units:degrees

    LON_WGS84
    longitude WGS84 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-153.9005963
    Maximum:-152.5855291
    Units:degrees

    FLIGHT
    First two digits are Fugro's EM bird identification number for the bird used for this job, i.e., '29'. The last three digits represent the flight numbers associated with this project. A flight number is the number of the helicopter flight from home base to home base associated with this project. The flights are numbered from the beginning of the project to the end. Only those flight numbers containing acquisition of final data measurements are included in the database. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:29005
    Maximum:29053
    Units:flight

    DATE
    range of flight dates (yyyy/mm/dd) for production flights (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:2009/08/11
    Maximum:2009/08/29
    Units:day

    ALTBIRD
    bird height above surface, measured with laser altimeter (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:14.14
    Maximum:203.63
    Units:m

    GPSZ
    bird height above spheroid. The GPSZ (or GPS-Z) value is primarily dependent on the number of available satellites. Although post-processing of GPS data will yield X and Y accuracies on the order of 1 meter, the accuracy of the Z value is usually much less, sometimes in the +/-20 meter range. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:96.00
    Maximum:1146.00
    Units:m

    DTM
    Digital terrain/elevation model (NAD27 UTM Zone 5N); data in m. Elevation calculation used for the digital elevation model is directly dependent on the accuracy of the two input parameters, ALTBIRD and GPSZ. The ALTBIRD value may be unreliable in areas of heavy tree cover, where the altimeter reflects the distance to the tree canopy rather than the ground. Although post-processing of GPS data will yield X and Y accuracies on the order of 1 meter, the accuracy of the Z value (GPSZ) is usually much less, sometimes in the +/-20 meter range. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:60.69
    Maximum:1108.24
    Units:m

    DIURNAL_FILT
    measured diurnal ground magnetic intensity; measured every 1.0 second (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:56491.01
    Maximum:56633.30
    Units:nT

    DIURNAL_COR
    diurnal correction - base removed (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-53.49
    Maximum:17.90
    Units:nT

    MAG_RAW
    total magnetic field - spike rejected (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55623.17
    Maximum:58782.73
    Units:nT

    MAG_LAG
    total magnetic field - corrected for lag (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55623.17
    Maximum:58689.14
    Units:nT

    MAG_DIU
    total magnetic field - diurnal variation removed (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55613.92
    Maximum:58690.93
    Units:nT

    IGRF
    international geomagnetic reference field for location and date (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:56644.99
    Maximum:56817.36
    Units:nT

    MAG_RMI
    residual magnetic intensity - IGRF removed, then leveled - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1193.84
    Maximum:1940.91
    Units:nT

    MAGIGRF
    mag_rmi with constant added back - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:55549.19
    Maximum:58683.94
    Units:nT

    CPI900_FILT
    900 Hz horizontal coplanar coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-151.83
    Maximum:1018.13
    Units:ppm

    CPQ900_FILT
    900 Hz horizontal coplanar coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-3.44
    Maximum:480.13
    Units:ppm

    CXI1000_FILT
    1000 Hz vertical coaxial coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-38.04
    Maximum:284.24
    Units:ppm

    CXQ1000_FILT
    1000 Hz vertical coaxial coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-5.49
    Maximum:119.65
    Units:ppm

    CXI5500_FILT
    5500 Hz vertical coaxial coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-28.2
    Maximum:367.05
    Units:ppm

    CXQ5500_FILT
    5500 Hz vertical coaxial coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-12.79
    Maximum:161.76
    Units:ppm

    CPI7200_FILT
    7200 Hz horizontal coplanar coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-87.56
    Maximum:1087.90
    Units:ppm

    CPQ7200_FILT
    7200 Hz horizontal coplanar coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:1.17
    Maximum:570.75
    Units:ppm

    CPI56K_FILT
    56 kHz horizontal coplanar coil-pair in-phase - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-25.01
    Maximum:1347.64
    Units:ppm

    CPQ56K_FILT
    56 kHz horizontal coplanar coil-pair quadrature - unlevelled (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-3.59
    Maximum:1085.73
    Units:ppm

    CPI900
    900 Hz horizontal coplanar coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-150.55
    Maximum:1015.33
    Units:ppm

    CPQ900
    900 Hz horizontal coplanar coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.25
    Maximum:480.05
    Units:ppm

    CXI1000
    1000 Hz vertical coaxial coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-35.36
    Maximum:280.50
    Units:ppm

    CXQ1000
    1000 Hz vertical coaxial coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-0.46
    Maximum:119.57
    Units:ppm

    CXI5500
    5500 Hz vertical coaxial coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-27.40
    Maximum:367.77
    Units:ppm

    CXQ5500
    5500 Hz vertical coaxial coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1.24
    Maximum:170.25
    Units:ppm

    CPI7200
    7200 Hz horizontal coplanar coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-87.44
    Maximum:1087.83
    Units:ppm

    CPQ7200
    7200 Hz horizontal coplanar coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-0.21
    Maximum:570.76
    Units:ppm

    CPI56k
    56 kHz horizontal coplanar coil-pair in-phase - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-19.98
    Maximum:1347.88
    Units:ppm

    CPQ56k
    56 kHz horizontal coplanar coil-pair quadrature - final (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.35
    Maximum:1085.97
    Units:ppm

    RES900
    apparent resistivity - 900 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.50
    Maximum:1325.00
    Units:ohm·m

    RES7200
    apparent resistivity - 7200 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:1.41
    Maximum:10750.00
    Units:ohm·m

    RES56K
    apparent resistivity - 56 kHz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:4.05
    Maximum:60000.00
    Units:ohm·m

    DEP900
    apparent depth - 900 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-79.09
    Maximum:270.15
    Units:m

    DEP7200
    apparent depth - 7200 Hz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-85.12
    Maximum:125.30
    Units:m

    DEP56K
    apparent depth - 56 kHz (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-96.81
    Maximum:40.61
    Units:m

    DIFI
    difference function in-phase; based on CXI5500 & CPI7200 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-28.84
    Maximum:110.27
    Units:unitless

    DIFQ
    difference function quadrature; based on CXQ5500 & CPQ7200 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-12.04
    Maximum:57.01
    Units:unitless

    CPPL
    coplanar powerline monitor (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.00
    Maximum:0.00
    Units:unitless

    CXSP
    coaxial spherics monitor (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.00
    Maximum:0.00
    Units:unitless

    CPSP
    coplanar spherics monitor (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.00
    Maximum:0.00
    Units:unitless

    Moran_RAD.GDB and Moran_RAD.XYZ
    The file 'Moran_RAD' contains raw and processed linedata and related calculated fields for locational and radiometric data. The linedata file is provided in Geosoft binary grid (GRD) and Geosoft ASCII XYZ (XYZ) formats. Except for the 'LINE' attribute, all attributes, including 'DATE' and 'FLIGHT', are represented by one of the 31 data columns on each record. The 'LINE' and 'FLIGHT' attributes are discussed further in the attribute 'ID Cell'. (Source: L.E. Burns & Fugro Airborne Surveys)

    ID_CELL
    The 'ID CELL' occurs in the GDB file only; the contents of the 'ID CELL' are also present in the XYZ file. In the 'ID CELL' for this project, the 'LINE' attribute is followed by a colon followed by the 'FLIGHT' attribute, e.g. 'L10010:29010' and 'T19010:29017'. More than one line is typically flown on a particular date and flight; more than one flight may be flown on a particular date. Each ID-cell value will have an associated spreadsheet view consisting of a column for each of the 31 attributes (30 in the XYZ file). In the XYZ file, the 'LINE' and 'FLIGHT' attributes and the 'DATE' are present as header lines, one attribute per line, before each set of associated data, e.g.

      //Flight 29010
      //Date 2009/08/12
      Line 10010  (or 'Tie 10950', etc.)
      Followed by all records for points sampled along Line 10010.
         (Pattern is repeated for each line number).
    
    The 'ID CELL' content, particularly combined with the definitions below for this particular survey, provides information about the flight line layout. (Source: L.E. Burns & Fugro Airborne Surveys)

    Definitions of the 'LINE' and 'FLIGHT' attributes are listed below.

     LINE TYPES and SYMBOLS:
     Traverse lines – oriented nominally N-S (0 degrees);
     Tie lines      - oriented nominally E-W (90 degrees); and
     Border lines   - present inside and parallel the survey
                      tract border where traverse or tie lines
                      are not parallel to the border.
     Traverse lines – 'L' (GDB file); 'LINE' (XYZ file).
     Tie and border lines - 'T' (GDB file); 'TIE' (XYZ file).
     LINE NUMBERS
     In general, the traverse lines increase by 10 from west to
     east; the tie lines increase by 10 from north to south; and
     the border lines increase by 10 starting for this project
     in the south-central edge of the survey area and continuing in
     a clockwise direction until reaching the southeastern part.
    
     When more than one uninterrupted flight segment was needed
     to complete a planned flight line, the fifth digit is
     increased by '1' for each new flight version.
     MAIN LINE NUMBERS:
        Lowest Traverse Lines: L10010 (west)
        Highest Traverse Lines: L11520 (east)
        Lowest Tie Lines: T19010 (north)
        Highest Tie Lines: T19080 (south)
        Lowest Border Lines: T19090 (south-central, progressing
        in clockwise direction)
        Highest Border Lines: T19130 (southeast)
    ------------------------------------------------------------
     'FLIGHT' DESIGNATORS
     The 5 digit flight designator consists of a two digit Fugro
     Dighem V system number (29 for this project) and a three
     digit flight identification number, e.g. '008'.
    

    X_NAD27z5N
    easting NAD27 (UTM Zone 5N) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:458130.23
    Maximum:519205.96
    Units:m

    Y_NAD27z5N
    northing NAD27 (UTM Zone 5N) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:7225239.02
    Maximum:7260818.41
    Units:m

    FID
    Fiducial increment; the time in tenths of seconds from the start to the end of the particular flight. Sampling typically occurred at each fiducial for almost all items in the database. (Source: Fugro Airborne Surveys)

    The attribute measurement resolution is 0.1 second. The values increase from the beginning of a flight to the end. Only FIDs during production flights are included in the database.

    LAT_WGS84
    latitude WGS84 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:65.1520411
    Maximum:65.4713032
    Units:degrees

    LON_WGS84
    longitude WGS84 (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-153.9005963
    Maximum:-152.5855291
    Units:degrees

    FLIGHT
    First two digits are Fugro's EM bird identification number for the bird used for this job, i.e., '29'. The last three digits represent the flight numbers associated with this project. A flight number is the number of the helicopter flight from home base to home base associated with this project. The flights are numbered from the beginning of the project to the end. Only those flight numbers containing acquisition of final data measurements are included in the database. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:29005
    Maximum:29053
    Units:flight

    DATE
    flight date (yyyy/mm/dd) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:2009/08/11
    Maximum:2009/08/29
    Units:day

    ALTRAD
    helicopter height above surface from radar altimeter (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:42.40
    Maximum:202.60
    Units:m

    DTM
    Digital terrain/elevation model (NAD27 UTM Zone 5N); data in m. Elevation calculation used for the digital elevation model is directly dependent on the accuracy of the two input parameters, ALTBIRD and GPSZ. The ALTBIRD value may be unreliable in areas of heavy tree cover, where the altimeter reflects the distance to the tree canopy rather than the ground. Although post-processing of GPS data will yield X and Y accuracies on the order of 1 meter, the accuracy of the Z value (GPSZ) is usually much less, sometimes in the +/-20 meter range. (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:60.69
    Maximum:1108.24
    Units:m

    TC_RAW
    raw total counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:123
    Maximum:4448
    Units:counts

    Th_RAW
    raw thorium counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0
    Maximum:190
    Units:counts

    U_RAW
    raw uranium counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:1
    Maximum:150
    Units:counts

    K_RAW
    raw potassium counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:5
    Maximum:369
    Units:counts

    U_UP
    raw upward looking uranium (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0
    Maximum:21
    Units:counts

    Cosmic
    cosmic counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:59.58
    Maximum:116.76
    Units:cps (counts per second)

    EffectiveHeight
    effective height at STP (standard temperature and pressure) (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:37.14
    Maximum:202.92
    Units:m

    LIVETIME
    live time (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:999
    Maximum:999
    Units:ms (millisecond)

    KPA
    barometric pressure (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:87.28
    Maximum:100.09
    Units:kPa (kilopascal)

    TEMP_EXT
    external temperature in Celsius (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:2.0
    Maximum:17.2
    Units:°C

    TC_cc
    corrected total counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-58.82
    Maximum:3917.05
    Units:cps (counts per second)

    Th_cc
    corrected thorium counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-4.98
    Maximum:175.32
    Units:cps (counts per second)

    U_cc
    corrected uranium counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.87
    Maximum:18.64
    Units:cps (counts per second)

    K_cc
    corrected potassium counts (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-15.53
    Maximum:255.51
    Units:cps (counts per second)

    eU
    uranium concentration (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-2.08
    Maximum:19.49
    Units:ppm

    eTh
    thorium concentration (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-1.32
    Maximum:46.38
    Units:ppm

    percentK
    potassium concentration (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-0.27
    Maximum:4.39
    Units:%

    ratio_eU_percentK
    uranium/potassium concentration ratio (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.01
    Maximum:286.70
    Units:ppm/%

    ratio_eTh_percentK
    thorium/potassium concentration ratio (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.02
    Maximum:396.92
    Units:ppm/%

    ratio_eU_eTh
    uranium/thorium concentration ratio (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:0.00
    Maximum:136.41
    Units:ppm/ppm

    nadr
    natural air absorbed dose rate (Source: Fugro Airborne Surveys)

    Range of values
    Minimum:-6.33
    Maximum:193.22
    Units:nGy/h (nanogray / hour)

    Spec256_DOWN
    radiometric spectrum; present in the GDB file, but not the XYZ file. (Source: Fugro Airborne Surveys)

    The radiometric spectrum for each sample point is in the form of an array.

    GPR2010-1GridsGRD.zip and GPR2010-1ERS.zip
    The zip files contain the nineteen grids and supporting files for this publication in either Geosoft binary float (GRD) format or ER Mapper (ERS) format. Each grid is in NAD27 datum, UTM Zone 5N, and has a 25m cell size with x and y in meters. Grid files are listed below as attributes.
    
    
    Two supporting files, a Geosoft projection file (GI) and a Geosoft v7-produced metadata file (XML), are included for each Geosoft grid file. The Geosoft grid is viewable (or importable into other software) without using these supported files. When using Geosoft, the GI file automatically sets the projection of the grid if the GI file is placed in the same directory as the grid file (GRD). Setting the projection can also be done manually in Geosoft without the GI file.
    
    
    Each ER Mapper grid consists of two files, a header (projection) file (.ERS) and a data file (no extension). Both ER Mapper files are necessary to view a grid or to convert it to another software format. (Source: Fugro Airborne Surveys)

    Moran_magigrf
    Total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); magnetic value in nanoTeslas (nT). (Source: Fugro Airborne Surveys)

    Grid file

    Moran_cvg
    Calculated vertical gradient (first vertical derivative 'dz') of the total magnetic field with IGRF removed; dz in nT/m. (Source: Fugro Airborne Surveys)

    Grid file

    Moran_analytic_signal
    Analytic signal calculated from the total magnetic field with IGRF removed (nT/m) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_tilt_derivative
    Tilt derivative of the total magnetic field with IGRF removed (degrees) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_res56k
    Apparent coplanar resistivity for 56,000 (56k) Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    Grid file

    Moran_res7200
    Apparent coplanar resistivity for 7200 Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    Grid file

    Moran_res900
    Apparent coplanar resistivity for 900 Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. (Source: Fugro Airborne Surveys)

    Grid file

    Moran_dtm
    Digital terrain or elevation model (m) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_K_cc
    Corrected thorium counts (cps) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_Th_cc
    Corrected thorium counts (cps) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_U_cc
    Corrected uranium counts (cps) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_TC_cc
    Corrected total counts (cps) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_percentK
    Percent potassium (%) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_eTh
    Equivalent thorium (ppm) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_eU
    Equivalent uranium (ppm) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_ratio_eTh_percentK
    Equivalent thorium / percent potassium ratio (ppm/%) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_ratio_eU_percentK
    Equivalent uranium / percent potassium ratio (ppm/%) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_ratio_eU_eTh
    Equivalent uranium / equivalent thorium ratio (ppm/%) (Source: Fugro Airborne Surveys)

    Grid file

    Moran_nadr
    Natural air absorbed dose rate [nGy/h (nanogray per hour)] (Source: Fugro Airborne Surveys)

    Grid file

    GPR2010-1TIFS_NAD27_z5N.zip
    The zip file 'GPR2010-1TIFS_NAD27_z5N.zip' contains Geotiffs in NAD27, UTM Zone 5N. Each of the 19 grids and a radiometric ternary image is represented in Geotiff (TIF) format. The images shown in 15 of the Geotiffs are the same images used on the maps in this publication; no maps were made of the other 5 images. Map numbers are given below for the appropriate Geotiff attribute definition; the correlation between Geotiff image and map number is also given in 'gpr2010_001_readme.pdf'. (Source: Fugro Airborne Surveys)

    Moran_magigrf
    Total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); magnetic value in nanoTeslas (nT). Map numbers GPR2010-1-1A, 1B, 2A, and 2B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_cvg
    Calculated vertical gradient (first vertical derivative 'dz') of the total magnetic field with IGRF removed; dz in nT/m. Map numbers GPR2010-1-3A and 3B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_analytic_signal
    Analytic signal calculated from the total magnetic field with IGRF removed (nT/m). Map numbers GPR2010-1-10A, 10B, 11A, and 11B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_tilt_derivative
    Tilt derivative of the total magnetic field with IGRF removed (degrees). Map numbers GPR2010-1-12A, 12B, 13A, and 13B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_res56k
    Apparent coplanar resistivity for 56,000 (56k) Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. Map numbers GPR2010-1-4A, 4B, 5A, and 5B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_res7200
    Apparent coplanar resistivity for 7200 Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. Map numbers GPR2010-1-6A, 6B, 7A, and 7B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_res900
    Apparent coplanar resistivity for 900 Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. Map numbers GPR2010-1-8A, 8B, 9A, and 9B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_dtm
    Digital terrain or elevation model (m); no map produced. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_K_cc
    Corrected potassium counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_Th_cc
    Corrected thorium counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_U_cc
    Corrected uranium counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_TC_cc
    Corrected total counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_percentK
    Percent potassium (%). Map numbers GPR2010-1-20A, 20B, 21A, and 21B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_eTh
    Equivalent thorium (ppm). Map numbers GPR2010-1-22A, 22B, 23A, and 23B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_eU
    Equivalent uranium (ppm). Map numbers GPR2010-1-24A, 24B, 25A, and 25B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_ratio_eTh_percentK
    Equivalent thorium / percent potassium ratio (ppm/%). Map numbers GPR2010-1-14A, 14B, 15A, and 15B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_ratio_eU_percentK
    Equivalent uranium / percent potassium ratio (ppm/%). Map numbers GPR2010-1-16A, 16B, 17A, and 17B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_ratio_eU_eTh
    Equivalent uranium / equivalent thorium ratio (ppm/%). Map numbers GPR2010-1-18A, 18B, 19A, and 19B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_nadr
    Natural air absorbed dose rate [nGy/h (nanogray per hour)]. Map numbers GPR2010-1-26A, 26B, 27A, and 27B. (Source: Fugro Airborne Surveys)

    Geotiff file

    Moran_ternary
    Radiometric ternary image; percent K = x axis (horizontal); equivalent Th = y axis (perpendicular horizontal axis shown at an angle), and equivalent U = z axis (vertical). Map numbers GPR2010-1-28A and 28B. (Source: Fugro Airborne Surveys)

    Geotiff file

    GPR2010-1KMZS_WGS84.zip
    The zip file 'GPR2010-1KMZS_WGS84.zip' contains Google Earth KMZ files in Geographic Coordinate System (Simple Cylindrical projection) with a WGS84 datum. Each of the 19 grids and a radiometric ternary image is included. The images shown in 15 of the KMZ files are the same images used on the maps in this publication; no maps were made of the other 5 images. Map numbers are given below for the appropriate KMZ attribute definition; the correlation between KMZ image and map number is also given in 'gpr2010_001_readme.pdf'. (Source: Fugro Airborne Surveys)

    Moran_magigrf
    Total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); magnetic value in nanoTeslas (nT). Map numbers GPR2010-1-1A, 1B, 2A, and 2B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_cvg
    Calculated vertical gradient (first vertical derivative 'dz') of the total magnetic field with IGRF removed; dz in nT/m. Map numbers GPR2010-1-3A and 3B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_analytic_signal
    Analytic signal calculated from the total magnetic field with IGRF removed (nT/m). Map numbers GPR2010-1-10A, 10B, 11A, and 11B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_tilt_derivative
    Tilt derivative of the total magnetic field with IGRF removed (degrees). Map numbers GPR2010-1-12A, 12B, 13A, and 13B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_res56k
    Apparent coplanar resistivity for 56,000 (56k) Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. Map numbers GPR2010-1-4A, 4B, 5A, and 5B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_res7200
    Apparent coplanar resistivity for 7200 Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. Map numbers GPR2010-1-6A, 6B, 7A, and 7B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_res900
    Apparent coplanar resistivity for 900 Hz.; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m. Map numbers GPR2010-1-8A, 8B, 9A, and 9B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_dtm
    Digital terrain or elevation model (m); no map produced. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_K_cc
    Corrected potassium counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_Th_cc
    Corrected thorium counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_U_cc
    Corrected uranium counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_TC_cc
    Corrected total counts (cps); no map produced. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_percentK
    Percent potassium (%). Map numbers GPR2010-1-20A, 20B, 21A, and 21B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_eTh
    Equivalent thorium (ppm). Map numbers GPR2010-1-22A, 22B, 23A, and 23B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_eU
    Equivalent uranium (ppm). Map numbers GPR2010-1-24A, 24B, 25A, and 25B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_ratio_eTh_percentK
    Equivalent thorium / percent potassium ratio (ppm/%). Map numbers GPR2010-1-14A, 14B, 15A, and 15B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_ratio_eU_percentK
    Equivalent uranium / percent potassium ratio (ppm/%). Map numbers GPR2010-1-16A, 16B, 17A, and 17B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_ratio_eU_eTh
    Equivalent uranium / equivalent thorium ratio (ppm/%). Map numbers GPR2010-1-18A, 18B, 19A, and 19B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_nadr
    Natural air absorbed dose rate [nGy/h (nanogray per hour)]. Map numbers GPR2010-1-26A, 26B, 27A, and 27B. (Source: Fugro Airborne Surveys)

    KMZ file

    Moran_ternary
    Radiometric ternary image; percent K = x axis (horizontal); equivalent Th = y axis (perpendicular horizontal axis shown at an angle), and equivalent U = z axis (vertical). Map numbers GPR2010-1-28A and 28B. (Source: Fugro Airborne Surveys)

    KMZ file

    Entity_and_Attribute_Overview:
    Data contours produced from the grids are provided as vector files for thirteen of the grids. These vector files are shown on the maps without topography. Additional vector files included are the flight path and Alaska Section Grid for the map area. These fifteen vector files are distributed into three zip files ('GPR2010-1Vectors1of3_Mag', 'GPR2010-1Vectors2of3_ResEtAl', and 'GPR2010-1Vectors3of3_Rad') for smaller downloads. Each of these zip files has a separate 'Detailed_Entity' section.

    All vector files are provided in Autocad DXF format, v2000, except for the flight path. All of the alphanumeric–appearing characters in the DXF files are alphanumeric characters, which are shifted when imported into any version of MapInfo Professional, Geosoft, and presumably other GIS programs. To provide alphanumeric characters in appropriate places for the critical flight path and Range labels in GIS programs besides Autocad, we are providing the flight path file (name starts with 'Moran_fp_') as an ESRI shape (SHP) file and the text part of the Alaska Section Grid file ('Moran_SecGrid.dxf') as a MapInfo Professional table (TAB) file. The text part of the section grid DXF file is also included. The alphanumeric numbers for the data contours for all the maps are shifted about 0.05 miles [80 m; 0.05 inches at map scale (1:63,360-scale)] to the right and up from where they should be when looked at with the number right-side-up. The files are understandable upon examination, and were not corrected.

    Entity_and_Attribute_Detail_Citation:
    L.E. Burns, Division of Geological & Geophysical Surveys and Fugro Airborne Surveys
    GPR2010-1Vectors1of3_Mag.zip
    Zip file contains contours for three (magigrf, analytic signal, and tilt derivative) of the four magnetic or derivative magnetic grids. Contours for the fourth type of magnetic grid, the first vertical derivative, were not produced. All files in this zip file, '…1 of 3…', are in Autocad DXF, v. 2000 format. The alphanumeric numbers for the contours are shifted about 0.05 inches at map scale to the right and up, and should be viewed carefully. (Source: Fugro Airborne Surveys)

    Moran_magigrf
    Total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); magnetic value in nanoTeslas (nT); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_analytic_signal
    Analytic signal of the total magnetic field with IGRF removed; value in nanoTeslas (nT/m); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_tilt_derivative
    Tilt derivative of the total magnetic field with IGRF removed; value in degrees; DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    GPR2010-1Vectors2of3_ResEtAl.zip
    Zip file contains vectors of data contours in Autocad DXF format for three resistivity grids (56,000 Hz, 7200 Hz, and 900 Hz). The alphanumeric numbers for the data contours are shifted about 0.05 inches at map scale to the right and up, and should be viewed carefully. The other files in this zipped file are for the flight path ('Moran_fp_Z' where Z = digits) or the Alaska (township/range) Section Grid ('Moran_SecGrid_X, where X = letters). When importing either of these files from DXF v 2000 to MapInfo Professional, Geosoft, and presumably other programs, the text was shifted to the left. This problem was solved in a different way for each file. The DXF file Moran_SecGrid contains four layers needed to complete an overlay of the township-range grid for the map areas. The GRIDTEXT layer in that DXF file shifts the text to the left, and though included here as part of the dxf, is also included as a corrected MapInfo Professional TAB file. The flight path file was imported by Fugro Airborne Surveys into MapInfo Professional and each individual layer was painstakingly moved. The flight path was then exported into ESRI SHAPE file format, and now consists of 4 shape files and 16 supporting files, all 20 of which start with 'Moran_FP_'. The flight path is not included on any map in this publication, but may be used as an overlay or printed by itself. (Source: Fugro Airborne Surveys)

    Moran_res56k
    Apparent coplanar resistivity for 56,000 (56k) Hz; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m; DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_res7200
    Apparent coplanar resistivity for 7200 Hz; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m; DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_res900
    Apparent coplanar resistivity for 900 Hz; calculated using a pseudo-layer half-space model; apparent resistivity in ohm-m; DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_fp_1
    One of four ESRI SHAPE files containing information about the flight path. This file contains all flight lines. (Source: Fugro Airborne Surveys)

    vector file containing lines for all flight lines

    Moran_fp_3
    One of four ESRI SHAPE files containing information about the flight path. This file contains tic marks and associated alphanumeric numbers, for fiducial marks (FIDs) ending in '00' and '50' as well as tic marks for beginning and ending FIDs regardless of the FID value. Lyn Vanderstarren of Fugro Airborne surveys manually corrected the placement of the text. (Source: Fugro Airborne Surveys)

    vector file containing lines and numbers for major FIDs and beginning and ending FIDs

    Moran_fp_2
    One of four ESRI SHAPE files containing information about the flight path. This file contains tic marks for fiducial marks (FIDs) ending in '10', '20', '30', '40', '60', '70', '80', and '90'. These fiducial tics are not labeled with any numbers. (Source: Fugro Airborne Surveys)

    vector file containing lines for minor FIDs

    Moran_fp_1001
    One of four ESRI SHAPE files containing information about the flight path. This file contains individual alphanumeric characters which form the line numbers and flight numbers. Between each line number and associated flight number, a '<' or '>' points in the direction of flight. Lyn Vanderstarren of Fugro Airborne surveys manually corrected the placement of the text. (Source: Fugro Airborne Surveys)

    vector file containing alphanumeric characters

    Moran_SecGrid
    Alaska PLSS Section Grid (original file name 'pls_section') for the map areas in DXF, v. 2000 format.; reprojected to NAD27, UTM Zone 5N, and modified by Fugro Airborne Surveys for line width, color, township and range numbers for the maps, and map borders. A text layer with alphanumeric characters is included, but can be turned off if the text is offset to the left in the GIS view. The text is also provided in a MapInfo TAB file, described as the next attribute. (See the vector 'Overview_Description' for explanation.) (Source: Alaska Department of Natural Resources - Land Records Information Section; L.E. Burns, Division of Geological & Geophysical Surveys; and Fugro Airborne Surveys)

    vector file containing alphanumeric characters shifted slightly to the left and down, and lines in the correct places

    MORAN_SECGRID_GRIDTEXT
    The alphanumeric text layer for the Alaska PLSS Section Grid for the map areas in MapInfo Professional TAB format. Range labels were shifted by hand to the right for proper viewing in MapInfo Professional and Geosoft. (See the vector 'Overview_Description' for more explanation.) (Source: Alaska Department of Natural Resources - Land Records Information Section; L.E. Burns, Division of Geological & Geophysical Surveys; and Fugro Airborne Surveys)

    file containing alphanumeric characters

    GPR2010-1Vectors3of3_Rad.zip
    Zip file contains contours for the seven radiometric grids. These files are in Autocad DXF, v. 2000 format. The alphanumeric numbers for the contours are shifted about 0.05 inches at map scale to the right and up, and should be viewed carefully. (Source: Fugro Airborne Surveys)

    Moran_percentK
    Percent potassium (%); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_eTh
    Equivalent thorium (ppm); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_eU
    Equivalent uranium (ppm); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_ratio_eTh_percentK
    Equivalent thorium / percent potassium ratio (ppm/%); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_ratio_eU_percentK
    Equivalent uranium / percent potassium ratio (ppm/%); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_ratio_eU_eTh
    Equivalent uranium / equivalent thorium ratio (ppm/%); DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Moran_nadr
    Natural air absorbed dose rate [nGy/h (nanogray per hour)]; DXF, v. 2000 format. (Source: Fugro Airborne Surveys)

    vector file containing numbers shifted slightly to the right and up, and lines in the correct places

    Entity_and_Attribute_Overview:
    Maps are provided in PDF and HPGL/2 format, and are distributed into five zip files for shorter downloads. Map type (PDF vs HPGL2) and the range of included maps numbers are stated in each zip file name. The HPGL/2 files have brighter and more gradational colors and sharper topography than the Adobe Acrobat files. See 'Technical_Prerequisites' section for more information on printing HPGL/2 maps.

    Two map sheets, labeled 'A' and 'B', are needed to cover the survey area at a scale of 1:63,360 (inch-to-a-mile). Twenty-eight different maps (56 map sheets) are included in this publication. Bounding coordinates for the sheets are given immediately below.

    ** 'A' maps – Part of Melozitna Quadrangle ******

       West, -154.00
       East, -153.25
       North, 65.50
       South, 65.13
    
    ** 'B' maps - Parts of Melozitna and Tanana quadrangles *******
       West, --153.25
       East, -152.50
       North, 65.50
       South, 65.13
    
    Authors and titles of the maps are like the example given below:

    Burns, L.E., Fugro Airborne Surveys Corp., and Stevens Exploration Management Corp., 2010, Total magnetic field of the Moran Survey Area, south-central Melozitna mining district, central Alaska, parts of Melozitna and Tanana quadrangles: Alaska Division of Geological & Geophysical Surveys Geophysical Report 2010-1-1A, 1 sheet, scale 1:63,360.

    Most geophysical images are placed on two maps; one with topography and one with data contours and no topography. A table clearly showing information about the maps (numbers, type of image, and whether topography or data contours are included) is located in 'gpr2010_001_readme.pdf' included with this publication.

    Entity_and_Attribute_Detail_Citation:
    L.E. Burns, Division of Geological & Geophysical Surveys, and Fugro Airborne Surveys
    GPR2010-1MapsAsPDFS_1-14.zip, GPR2010-1MapsAsPDFS_15-28.zip, GPR2010-1MapsAsHPGL2_1-9.zip, GPR2010-1MapsAsHPGL2_10-19.zip, and GPR2010-1MapsAsHPGL2_20-28.zip
    Zip file names indicate the map numbers and format included in the zip file. (Source: Fugro Airborne Surveys)

    GPR2010-1-1A
    Western map; total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); includes topography; magnetic value in nanoTeslas (nT). Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-1B
    Eastern map; total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); includes topography; magnetic value in nanoTeslas (nT). Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-2A
    Western map; total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); includes data contours; magnetic value in nanoTeslas (nT). Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-2B
    Eastern map; total magnetic field with IGRF removed (i.e., residual magnetic field with constant added back in); includes data contours; magnetic value in nanoTeslas (nT). Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-3A
    Western map; calculated vertical gradient (first vertical derivative 'dz') of the total magnetic field with IGRF removed; includes topography; dz in nT/m. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-3B
    Eastern map; calculated vertical gradient (first vertical derivative 'dz') of the total magnetic field with IGRF removed; includes topography; dz in nT/m. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-4A
    Western map; apparent coplanar resistivity for 56,000 (56k) Hz.; includes topography. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-4B
    Eastern map; apparent coplanar resistivity for 56,000 (56k) Hz.; includes topography. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-5A
    Western map; apparent coplanar resistivity for 56,000 (56k) Hz.; includes data contours. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-5B
    Eastern map; apparent coplanar resistivity for 56,000 (56k) Hz.; includes data contours. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-6A
    Western map; apparent coplanar resistivity for 7200 Hz.; includes topography. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-6B
    Eastern map; apparent coplanar resistivity for 7200 Hz.; includes topography. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-7A
    Western map; apparent coplanar resistivity for 7200 Hz.; includes data contours. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-7B
    Eastern map; apparent coplanar resistivity for 7200 Hz.; includes data contours. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-8A
    Western map; apparent coplanar resistivity for 900 Hz.; includes topography. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-8B
    Eastern map; apparent coplanar resistivity for 900 Hz.; includes topography. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-9A
    Western map; apparent coplanar resistivity for 900 Hz.; includes data contours. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-9B
    Eastern map; apparent coplanar resistivity for 900 Hz.; includes data contours. Apparent resistivity (in ohm m) calculated using a pseudo-layer half-space model. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_1-9.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-10A
    Western map; analytic signal calculated from the total magnetic field with IGRF removed (nT/m); includes topography. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-10B
    Eastern map; analytic signal calculated from the total magnetic field with IGRF removed (nT/m); includes topography. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-11A
    Western map; analytic signal calculated from the total magnetic field with IGRF removed (nT/m); includes data contours. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-11B
    Eastern map; analytic signal calculated from the total magnetic field with IGRF removed (nT/m); includes data contours. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-12A
    Western map; tilt derivative of the total magnetic field with IGRF removed (degrees); includes topography. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-12B
    Eastern map; tilt derivative of the total magnetic field with IGRF removed (degrees); includes topography. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-13A
    Western map; tilt derivative of the total magnetic field with IGRF removed (degrees); includes data contours. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-13B
    Eastern map; tilt derivative of the total magnetic field with IGRF removed (degrees); includes data contours. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-14A
    Western map; equivalent thorium / percent potassium ratio (ppm/%); includes topography. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-14B
    Eastern map; equivalent thorium / percent potassium ratio (ppm/%); includes topography. Map contained in GPR2010-1MapsAsPDF_1-14.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-15A
    Western map; equivalent thorium / percent potassium ratio (ppm/%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-15B
    Eastern map; equivalent thorium / percent potassium ratio (ppm/%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-16A
    Western map; equivalent uranium / percent potassium ratio (ppm/%); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-16B
    Eastern map; equivalent uranium / percent potassium ratio (ppm/%); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-17A
    Western map; equivalent uranium / percent potassium ratio (ppm/%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-17B
    Eastern map; equivalent uranium / percent potassium ratio (ppm/%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-18A
    Western map; equivalent uranium / equivalent thorium ratio (ppm/%); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-18B
    Eastern map; equivalent uranium / equivalent thorium ratio (ppm/%); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-19A
    Western map; equivalent uranium / equivalent thorium ratio (ppm/%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-19B
    Eastern map; equivalent uranium / equivalent thorium ratio (ppm/%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_10-19.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-20A
    Western map; percent potassium (%); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-20B
    Eastern map; percent potassium (%); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-21A
    Western map; percent potassium (%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-21B
    Eastern map; percent potassium (%); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-22A
    Western map; equivalent thorium (ppm); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-22B
    Eastern map; equivalent thorium (ppm); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-23A
    Western map; equivalent thorium (ppm); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-23B
    Eastern map; equivalent thorium (ppm); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-24A
    Western map; equivalent uranium (ppm); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-24B
    Eastern map; equivalent uranium (ppm); includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-25A
    Western map; equivalent uranium (ppm); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-25B
    Eastern map; equivalent uranium (ppm); includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-26A
    Western map; natural air absorbed dose rate [nGy/h (nanogray per hour)]; includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-26B
    Eastern map; natural air absorbed dose rate [nGy/h (nanogray per hour)]; includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-27A
    Western map; natural air absorbed dose rate [nGy/h (nanogray per hour)]; includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-27B
    Eastern map; natural air absorbed dose rate [nGy/h (nanogray per hour)]; includes data contours. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-28A
    Western map; radiometric Ternary image; includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format

    GPR2010-1-28B
    Eastern map; radiometric Ternary image; includes topography. Map contained in GPR2010-1MapsAsPDF_15-28.zip and GPR2010-1MapsAsHPGL2_20-28.zip. (Source: Fugro Airborne Surveys)

    map in PDF and HPGL/2 format


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?

    Funding was provided by the Alaska State Legislature as part of the DGGS Airborne Geophysical/Geological Mineral Inventory (AGGMI) program.

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


Why was the data set created?

The survey was part of the Alaska Airborne Geophysical/Geological Mineral Inventory project funded by the Alaska State Legislature and managed by State of Alaska, Department of Natural Resources (DNR), Division of Geological & Geophysical Surveys (DGGS). The project seeks to catalyze private-sector mineral development investment. The project delineates mineral zones on Alaska state lands that: 1) have major economic value; 2) can be developed in the short term to provide high quality jobs for Alaska; and 3) will provide economic diversification to help offset the loss of Prudhoe Bay oil revenue.


How was the data set created?

  1. From what previous works were the data drawn?

    Akima, 1970 (source 1 of 3)
    Akima, H., 1970, A new method of interpolation and smooth curve fitting based on local procedures: Journal of the Association of Computing Machinery v. 7, no. 4.

    Online Links:

    • None

    Type_of_Source_Media: paper
    Source_Contribution:
    Fugro Airborne Surveys used a modification of this method while making grids.

    IAEA TECDOC-1363, 2003 (source 2 of 3)
    International Atomic Energy Agency, 2003, Guidelines for radioelement mapping using gamma ray spectrometry data: IAEA-TECDOC (Technical document) 1363.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    The radon detection system was calibrated following methods outlined in IAEA-TECDOC-1363.

    ADNR-LRIS, 1995 (source 3 of 3)
    Alaska Department of Natural Resources - Land Records Information Section, 1995, Alaska PLSS Section Grid: State of Alaska, Department of Natural Resources, Division, Land Records Information Section (LRIS), <http://mapper.landrecords.info/> (Anchorage, Alaska).

    Online Links:

    Other_Citation_Details: ESRI shape file format
    Type_of_Source_Media: online
    Source_Contribution:
    The downloaded section grid file, built from original protraction diagram data, was used as a starting point for the section grid digital file included in GPR2010-1 and used on the maps without topography and is provided in digital format in this publication. Minor formatting modifications were made to the file. The publication date given above reflects the current metadata file for the Alaska PLSS Section Grid.

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

    Date: 2009 (process 1 of 7)
    The airborne geophysical data were acquired with a DIGHEM(V) Electromagnetic (EM) system, Radiation Solutions RS-500 gamma-ray spectrometer, and a Fugro D1344 cesium magnetometer with a Scintrex CS3 cesium censor between August 11th to August 29th, 2009. The EM and magnetic sensors were flown at a height of 100 feet. The gamma-ray spectrometer was flown at a height of 200 feet. In addition, the survey recorded data from radar and laser altimeters, GPS navigation system, 50/60 Hz monitors, and video camera.
    
    
    Flights were performed with an AS350B-3 Squirrel helicopter at a mean terrain clearance of 200 feet along N-S (0 degrees) survey flight lines with one-quarter mile line spacing. Tie lines were flown perpendicular to the flight lines at intervals of approximately 3 miles.
    
    
    A Novatel OEM4-G2L Global Positioning System was used for navigation and flight path recovery. The helicopter position was derived every 0.5 seconds (2 Hz); the ground GPS base station data were collected at 0.1 second (10 Hz) intervals. The use of the differentially-corrected base station data results in a positional accuracy of better than one meter. The positional xy data are interpolated from 2 Hz to 10 Hz. Flight path positions were projected onto the Clarke 1866 (UTM zone 5) spheroid, 1927 North American datum using a central meridian (CM) of 153 degrees, a north constant of 0, and an east constant of 500,000.

    Date: 2009 (process 2 of 7)
    The total magnetic field data were acquired with a sampling interval of 0.1 seconds, and were (1) corrected for measured system lag (EM linedata field 'mag_lag'), (2) corrected for diurnal variations by subtraction of the digitally recorded base station magnetic data (EM linedata field 'mag_diu'), (3) adjusted for regional variations using date of flight and altimeter-adjusted IGRF, (4) leveled to the tie line data resulting in the final residual magnetic intensity (EM linedata field 'mag_rmi'), (5) increased by a constant to provide an IGRF-corrected total magnetic field column (EM linedata field 'magigrf') and (6) interpolated onto a regular 80-m grid using a modified Akima (1970) technique.
    
    
    The total magnetic field data were subjected to three processing algorithms for producing derivative grids. The vertical gradient algorithm enhances the response of magnetic bodies in the upper 500 m and attenuates the response of deeper bodies. The resulting (calculated) vertical gradient grid ('Moran-cvg') provides better definition and resolution of near-surface magnetic units. It also identifies weak magnetic features that may not be evident in the total field data.
    
    
    Analytic signal is the total amplitude of all directions of magnetic gradient calculated from the sum of the squares of the three orthogonal gradients. Mapped highs in the calculated analytic signal of the magnetic parameter locate the anomalous source body edges and corners (e.g., contacts, fault/shear zones, basement fault block boundaries or lithologic contacts, etc.). Analytic signal maxima are located directly over faults and contacts, regardless of structural dip, and independently of the direction of the induced and/or remanent body magnetizations.
    
    
    The calculated magnetic tilt derivative is the angle between the horizontal gradient and the total vertical gradient, which is useful for identifying the depth and type of magnetic source. The tilt angle is positive over the source, crosses through zero at, or near, the edge of a vertical sided source, and is negative outside the source zone. It responds equally well to shallow and deep sources and is able to resolve deeper sources that may be masked by larger responses caused by shallower sources.
    
    
    All magnetic grids were then resampled from the 80-m cell size down to a 25-m cell size using a modified Akima (1970) technique to produce the maps and final grids contained in this publication.

    Data sources used in this process:

    • Akima, 1970

    Date: 2009 (process 3 of 7)
    The DIGHEM V EM system measured inphase and quadrature components at five frequencies. Two vertical coaxial-coil pairs operated at 1070 (1000) and 5503 (5500) Hz while three horizontal coplanar-coil pairs operated at 925 (900), 7094 (7200), and 55,640 (56,000) Hz. EM data were sampled at 0.1 second intervals. The EM system responds to bedrock conductors, conductive overburden, and cultural sources. The EM inphase and quadrature data were drift corrected using base level data collected at high altitude (areas of no signal). Along-line filters are applied to the data to remove spheric spikes. The data were inspected for variations in phase, and a phase correction was applied to the data if necessary. Apparent resistivities were then calculated from the inphase and quadrature data for all coplanar frequencies based on a pseudo-layer half-space model. Manual leveling of the inphase and quadrature of each coil pair, based on the resistivity data and comparisons to the data from the other frequencies, was performed. Automated micro-leveling is carried out in areas of low signal. The EM data were interpolated onto a regular 80-m grid using a modified Akima (1970) technique. The resulting grids were subjected to a 3x3 Hanning filter and resampled to a 25-m cell size before contouring and map production.

    Data sources used in this process:

    • Akima, 1970

    Date: 2009 (process 4 of 7)
    The gamma-ray spectrometry data were recorded at a 1.0 second sample rate using a Radiation Solutions RS-500 gamma-ray spectrometer. It was configured with 16.8L (1024 cubic inches) of main (downward) NaI crystal detector, and 4.2L (256 cubic inches) of upward looking (radon) detector. After application of Noise Adjusted Singular Value Decomposition to the spectra, counts from the main detector were recorded in five windows corresponding to thorium (2410-2810 keV), uranium (1660-1860 keV), potassium (1370-1570 keV), total radioactivity (400-2815 keV) and cosmic radiation (3000->6000 keV). Counts from the radon detector were recorded in the radon window (1660-1860 keV). The radon detection system was calibrated following methods outlined in IAEA Report 1363. After removal of the background, the data were corrected for spectral interferences, changes in temperature, pressure, and departures from the planned survey elevation of 200 feet. The data were then converted to standard concentration units which were interpolated to a 100 m grid using a minimum curvature technique. All grids were then resampled from the 100 m cell size down to a 25 m cell size to produce the maps and final grids contained in this publication.

    Data sources used in this process:

    • IAEA TECDOC-1363, 2003

    Date: 2009 (process 5 of 7)
    The digital elevation/terrain model was produced from the differentially corrected GPS-Z data (EM linedata field 'GPSZ') and the laser altimeter data (EM linedata field 'ALTBIRD') measured in the bird. Both the GPSZ and ALTBIRD data were then checked for spikes, which were removed manually. The ALTBIRD data were despiked and then filtered using a 13 median filter, followed by a 13 Hanning filter. The corrected altimeter was then subtracted from the GPSZ data to produce profiles of the height above mean sea level along the survey lines. The data were manually leveled to remove any errors between lines. After all leveling, the data were DC shifted to match the local maps, in this case, NAD27. The 80-m DEM grid was then resampled to a 25-m cell size to produce the DEM grid contained in this publication.

    Date: 2010 (process 6 of 7)
    DGGS downloaded the Alaska PLSS Section Grid shapefile in fall 2009 and cut the file to fit the map sheets for this publication using MapInfo Professional. Fugro Airborne Surveys modified the formatting of the file using AutoCad, changing township and range line widths and colors, and added township and range labels. The modified file was then used as overlays on maps without topography. An additional format (MapInfo Professional tab file) of the township and range labels is provided because the text in the original dxf file is offset to the left when imported into most GIS programs.

    Data sources used in this process:

    • ADNR-LRIS, 1995

    Date: 2009 (process 7 of 7)
    The HPGL/2 files were created with HP Designjet 5000 printer driver v5.32 and plot on some plotters, but not all plotters correctly. The Adobe Acrobat format files were created with Adobe Acrobat Distiller 9.0 from Postscript files.

  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?

    Survey contracts specified the conditions and specifications under which these data were collected. Altimeter, heading, lag, and frequent EM calibrations were done. More information will be available in the project report to be published in the future.

  2. How accurate are the geographic locations?

    The helicopter position was derived every 0.5 seconds using post-flight differential positioning to an accuracy of better than 1 m.

  3. How accurate are the heights or depths?

    The radar altimeter ('ALTRAD') had a stated resolution of 0.3 meter, and an accuracy better than 10% of the flying height, i.e. better or equal to 4 meters for this survey. The ALTRAD value may be unreliable in areas of heavy tree cover, where the altimeter reflects the distance to the tree canopy rather than the ground.

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

    The linedata were distributed into two linedata files for ease of download. 'Moran_EM' contains magnetic and electromagnetic data; 'Moran_RAD' contains radiometric data. A maximum of 1,485,841 records (sampling points) were recorded for the magnetic and electromagnetic data, all of which were sampled at 0.1 second intervals. Most of the radiometric data were sampled every 1.0 seconds and hence have a maximum number of data points of 148,586. Few values are missing from the databases. The file 'gpr2010-001_readme.PDF' contains detailed information about how many dummy variables are present for each channel in the databases. A short summary is given here.

    Missing mag values occur in three different places in the survey area; 2 near the end of a border line or end of an overlapping tie line, and the third gap (Line 11110) was due to despiking. The magnetic gap on Line 11110 occurred for lagged magnetic data between fiducial marks (FIDs) 6862.7 and 6868.0. The length of the gap is about 150 m long for the magnetic values, and is larger than the footprint of the system; hence the magnetic data was not splined. Missing values in the apparent resistivity (res56k, res7200, and res900) and associated calculated 'depth' (dep56k, dep7200, and dep900) are due to calculations being meaningless, generally caused by increase in altitude. Only 2 values were missing from a few of the radiometric channels. A little over 9,000 are missing from the radiometric ratios because these are not calculated where the data values are too small for the ratios to be meaningful.

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

    Data for this survey were collected by a single subcontractor (Fugro Airborne Surveys) who was responsible for collecting and processing the data. All the data were collected with the same instruments (magnetometers, electromagnetic bird and sensors, gamma ray spectrometer, altimeters, and navigational system).


How can someone get a copy of the data set?

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

Access_Constraints:
This report, map and/or dataset are available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Use_Constraints:
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way the user is obligated to describe the types of modifications the user has made. User specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS).

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

    State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS)
    Natural Resource Technician
    3354 College Road
    Fairbanks, AK 99709-3707
    USA

    907-451-5020 (voice)
    907-451-5050 (FAX)
    dggspubs@alaska.gov

    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our Web site (<http://www.dggs.alaska.gov>) for the latest information on available data. Please contact us using the e-mail address above whenever possible.
  2. What's the catalog number I need to order this data set?

    Geophysical Report 2010-1

  3. What legal disclaimers am I supposed to read?

    The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product.

  4. How can I download or order the data?

  5. Is there some other way to get the data?

    Custom views or processing may be requested. Please contact Laurel Burns by phone (907-451-5021), e-mail (laurel.burns@alaska.gov), or fax (907-451-5050) to discuss custom processing availability, fees, and turnaround time.

  6. What hardware or software do I need in order to use the data set?

    Software with ability to use, import, or convert Geosoft float GRD, Geosoft binary GDB or ASCII XYZ files, Autocad DXF files, ESRI Shape files, MapInfo Professional TAB files, Adobe Acrobat PDF, Google Earth files, and text files. Free downloadable interfaces to view or convert the gridded and dxf files are available at the Geosoft Web site (<http://www.geosoft.com>; Oasis Montaj viewer). The KMZ files can be dragged and dropped into the 'My Places' folder of the free downloadable 'Google Earth' software. Freeware software 'printfile' (<http://www.lerup.com/printfile/>) prints HPGL/2 files easily on compatible printers. The HPGL/2 files have brighter colors and sharper topography than the PDF maps and should be used for printing when possible. The PDF format maps are the only maps digitally viewable in this publication.


Who wrote the metadata?

Dates:
Last modified: 04-May-2010
Last Reviewed: 04-May-2010
To be reviewed: 06-Apr-2011
Metadata author:
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS)
Geophysicist (Laurel Burns)
3354 College Road
Fairbanks, AK 99709-3707
USA

907-451-5021 (voice)
907-451-5050 (FAX)
dggspubs@alaska.gov

Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays.
Contact_Instructions:
Please contact us through the e-mail address above whenever possible.
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)


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