Bedrock geologic map of the Liberty Bell area, Fairbanks A-4 Quadrangle, Bonnifield mining district, Alaska

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What does this data set describe?

Title:
Bedrock geologic map of the Liberty Bell area, Fairbanks A-4 Quadrangle, Bonnifield mining district, Alaska
Abstract:
Report of Investigation 2006-2, "Bedrock geologic map of the Liberty Bell area, Fairbanks A-4 Quadrangle, Bonnifield mining district, Alaska," is the bedrock geologic map of an approximately 131-square-mile area surrounding the Liberty Bell Mine. The geology of the Liberty Bell area, located in the northern Alaska Range foothills, comprises Devonian metasedimentary and meta-igneous rocks of the Totatlanika Schist and Keevy Peak formations, Cretaceous and Tertiary igneous rocks, and overlying unconsolidated Tertiary sedimentary rocks of the Usibelli Group and the younger Nenana Gravel.
Supplemental_Information:
The dataset is comprised of the 32 layers, which compose the bedrock geologic map and the inset map. All 32 layers are available as shape (*.shp) files. Ten additional Arc Export (*.e00) files of annotation are also available for presentational purposes. Attribute information for the 22 non-annotation layers (entities) is included in this metadata file under the "Entity_and_Attribute_Information" section. Each layer is listed and described in detail under its own heading starting at "Entity_Type_Label." Basic unit information is included in a text document, "RI2006-2_codeset.pdf."
  1. How should this data set be cited?

    Athey, J.E., Newberry, R.J., Werdon, M.B., Freeman, L.K., Smith, R.L., and Szumigala, D.J., 2006, Bedrock geologic map of the Liberty Bell area, Fairbanks A-4 Quadrangle, Bonnifield mining district, Alaska: Report of Investigation RI 2006-2 v 1.0.1, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:50,000, 98 pp.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -149.0000
    East_Bounding_Coordinate: -148.5000
    North_Bounding_Coordinate: 64.1250
    South_Bounding_Coordinate: 64.0000

  3. What does it look like?

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

    Beginning_Date: 2005
    Ending_Date: 2006
    Currentness_Reference: publication date

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

    Geospatial_Data_Presentation_Form: Map 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: 6
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -147.00000
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000064
      Ordinates (y-coordinates) are specified to the nearest 0.000064
      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?

    ArAr.shp
    Point locations for Ar-Ar radiometric age samples, table contains 7 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    STATIONNO
    Generic example of unique sample identifier: YearAAA999X: Year=4 digits of year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:404906
    Maximum:425415
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7097762
    Maximum:7109006
    Units:meters

    ArAr_Anno
    Unique label identifying a sample location on the map (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier, one blank value is not represented on the map

    Lithology
    Lithology from which the sample was taken (Source: Alaska Division of Geological & Geophysical Surveys)

    Brief description of the sample lithology

    border.shp
    Polygon outlining the Liberty Bell map area, table contains one object, table contains no attributes (Source: Alaska Division of Geological & Geophysical Surveys)

    clinker.shp
    Polygons outlining areas of burned coal and coal-fired sedimentary rocks, table contains 19 objects, table contains no attributes (Source: Alaska Division of Geological & Geophysical Surveys)

    coal.shp
    Point locations for coal data, table contains 21 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    STATIONNO
    Generic example of unique sample identifier: YearAAA999X: Year=4 digits of year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:413860
    Maximum:422738
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7098584
    Maximum:7111956
    Units:meters

    COMMENTS
    Description of sample locality (Source: Alaska Division of Geological & Geophysical Surveys)

    Description of sample locality

    COAL_ANNO
    Unique label identifying a sample location on the map (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    contacts.shp
    Polylines for metamorphic-stratigraphic, intrusive, and fault contacts, table contains 776 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    linetype
    Type of contact (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    boundaryLine segment of the map border
    concealed faultFault covered by Quaternary and/or Tertiary units
    contactMetamorphic-stratigraphic or intrusive contacts
    faultHigh-angle fault
    fault gp queriedFault inferred from geophysical data (Burns and others, 2002), where its existence or location is uncertain
    inferred faultFault interpreted from aerial photography and (or) geophysical data (Burns and others, 2002)
    questionable faultFault where significant motion is unknown or location is unknown or uncertain
    uncertain contactContact where location is uncertain

    dikepoints.shp
    Point locations for unmetamorphosed dikes, table contains 52 objects, symbolized by composition (Source: Alaska Division of Geological & Geophysical Surveys)

    STATION
    Generic example of unique sample identifier: YearAAA999X: Year=4 digits of year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:403538
    Maximum:425195
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7098018
    Maximum:7111450
    Units:meters

    TYPE
    Orientation of intrusion with respect to host rock, dike versus sill (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    ?Orientation of intrusion is unknown
    dikeIntrusion is oriented at an angle to the foliation of its host rock
    sill?Intrusion may be oriented parallel to the foliation of its host rock

    Description of sample locality

    NAME
    Description of lithology (Source: Alaska Division of Geological & Geophysical Surveys)

    Description of lithology

    MAP_ABBREV
    Unit abbreviation associated with dike (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:RI2006-2_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys (<http://www.dggs.dnr.state.ak.us/metadata/RI2006-2_codeset.pdf>)

    dikes_oriented_point.shp
    Point locations showing strike or trend of unmetamorphosed dikes, table contains 17 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    STATION
    Generic example of unique sample identifier: YearAAA999X: Year=2 digit year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:404906
    Maximum:424440
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7101536
    Maximum:7106648
    Units:meters

    TYPE
    Orientation of intrusion with respect to host rock, dike versus sill (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    ?Orientation of intrusion is unknown
    dikeIntrusion is oriented at an angle to the foliation of its host rock
    sill?Intrusion may be oriented parallel to the foliation of its host rock

    Description of sample locality

    STRIKE
    Angle of strike or trend of dike, strike and dip recorded using "right-hand rule"; trend recorded where dip is not measurable; trend recorded in horizontal plane of dip-direction (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:10
    Maximum:345
    Units:degrees

    DIP
    Dip of the dike (if known). Strike and dip recorded using "right-hand rule". "0" degrees refers to dikes without measured dip; there are no horizontal sills in this dataset. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:90
    Units:degrees

    NAME
    Description of lithology (Source: Alaska Division of Geological & Geophysical Surveys)

    Description of lithology

    MAP_ABBREV
    Unit abbreviation associated with dike (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:RI2006-2_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys (<http://www.dggs.dnr.state.ak.us/metadata/RI2006-2_codeset.pdf>)

    dikes_oriented_polyline.shp
    Polyline showing dike location, table contains 1 object (Source: Alaska Division of Geological & Geophysical Surveys)

    NAME
    Description of lithology (Source: Alaska Division of Geological & Geophysical Surveys)

    Description of lithology

    faultsymbol.shp
    symbols and text point locations depicting fault information and relative fault movement, table contains 71 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    TEXTSTRING
    Map text for fault plane relative movement, named faults, and queried faults; blank where no text is required (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DDown-thrown side of fault
    UUp-thrown side of fault
    Eva Creek FaultEva Creek Fault
    ?Location or continuation of fault is unknown

    Symbol
    Map symbol for fault plane relative movement; blank where no map symbol is required (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    right lateralRight-lateral movement
    left lateralLeft-lateral movement

    foldaxes.shp
    polylines following axial traces of major folds, table contains 55 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    TYPE
    Type of fold (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    AntiformAntiform
    Antiform?Possible antiform
    concealed synformSynform covered by Tertiary units
    Interp SynformSynform interpreted from aerial photography or long-distance observation
    Interp AntiformAntiform interpreted from aerial photography or long-distance observation
    SynformSynform
    Synform?Possible synform

    foldsymbol.shp
    Symbols and text point locations showing fold types and orientations, table contains 77 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    TEXTSTRING
    Map text and symbols for fold types, orientations, and queried folds (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    ?Location or continuation of fold axis is unknown
    antiformAntiform
    inset antiformAntiform that appears only in the inset map
    inset plunge arArrow showing direction of fold plunge, appears only in the inset map
    inset synformSynform that appears only in the inset map
    Plunge arrowArrow showing direction of fold plunge
    synformSynform
    synform?Possible synform

    hornfels.shp
    Polygons outlining areas of hornfels and metasomatic alteration, table contains 26 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    ID
    Type of polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    hornfelsLocations of hornfels and metasomatic alteration

    INSET_border.shp
    Polygon outlining the inset map area, table contains 1 object (Source: Alaska Division of Geological & Geophysical Surveys)

    Type
    Type of polygon (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    borderLocation of inset map area

    INSET_foldaxes.shp
    Polylines on the inset map following axial traces of folds, table contains 8 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    TYPE
    Type of fold (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    antiformAntiform
    synformSynform

    INSET_RAAstructurepoints.shp
    Point locations of RAA structural measurements (Freeman and others, 1987), table contains 234 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    ANGLE
    Strike of plane in "right-hand rule", where north is 0 and degrees increase clockwise to 359 degrees (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:359
    Units:degrees

    DIP
    Degrees that a plane is inclined relative to horizontal, horizontal being 0 degrees, vertical being 90 degrees; always 90 degrees clockwise from strike (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:90
    Units:degrees

    ID
    Type of structure measurement to plot, to which the orientation data apply (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    faultFault, measurement from major fault in contacts table
    fault comMinor fault, measurement from probable minor fault, not associated with a fault in the contacts table
    fold axisMinor fold axis
    foliationFoliation
    h foliationHorizontal foliation
    jointjoint
    noshowStructural measurement not shown on the inset map, see attribute "structure" for the type of measurement
    v jointvertical joint
    veinvein

    REMARKS
    Description of measurement or lithology (Source: Alaska Division of Geological & Geophysical Surveys)

    Description of measurement or lithology

    EAST
    UTM Zone 6, NAD 27 (see Spatial_Reference_Information) (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:-148.87379
    Maximum:-148.84285
    Units:degrees

    NORTH
    UTM Zone 6, NAD 27 (see Spatial_Reference_Information) (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:64.0444
    Maximum:64.05839
    Units:degrees

    Structure
    Type of structure measurement, to which the orientation data apply, not all of these data are plotted on the inset map (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    faultFault, measurement from major fault in contacts table
    fault comMinor fault, measurement from probable minor fault, not associated with a fault in the contacts table
    fold axisMinor fold axis
    foliationFoliation
    h foliationHorizontal foliation
    jointjoint
    v jointvertical joint
    v veinVertical vein
    veinvein

    metadikes.shp
    Point locations for metamorphosed dikes, table contains 28 objects, symbolized by composition (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPNO
    Generic example of unique sample identifier: YearAAA999X: Year=4 digits of year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:405785
    Maximum:426621
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7099694
    Maximum:7111652
    Units:meters

    TYPE
    Type of lithology (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:RI2006-2_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys (<http://www.dggs.dnr.state.ak.us/metadata/RI2006-2_codeset.pdf>)

    paly.shp
    Point locations for pollen data, table contains 15 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPNO
    Generic example of unique sample identifier: YearAAA999X: Year=4 digits of year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. Two (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:405456
    Maximum:424592
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7098096
    Maximum:7111956
    Units:meters

    POL_ANNO
    Unique label identifying a sample location on the map (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier

    Lithology
    Short description of sample lithology (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    coalCoal
    shaleShale
    siltstoneSiltstone
    silty sandstoneSilty sandstone

    polygons.shp
    Polygons outlining bedrock units, table contains 270 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    UNIT
    Bedrock unit labels (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:RI2006-2_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys (<http://www.dggs.dnr.state.ak.us/metadata/RI2006-2_codeset.pdf>)

    structurepoints.shp
    Point locations of structural measurements, table contains 788 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    STATIONNO
    Generic example of unique sample identifier: YearAAA999X: Year=4 digit year of sample collection, AAA=geologist's initials (one to three characters), 999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials are: JEA - Jennifer Athey, LF - Lawrence Freeman, MBW - Melanie Werdon, RN - Rainer Newberry, Z - Dave Szumigala. (Source: Alaska Division of Geological & Geophysical Surveys)

    Unique sample identifier. Two blank values are fault measurements from Freeman and others (1987); values "air photo" indicate structure data interpreted from aerial photographs.

    EASTING
    Easting (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:402492
    Maximum:426708
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 6, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7097691
    Maximum:7112149
    Units:meters

    ID
    Type of structural measurement (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    air photoBedding measurement interpreted from aerial photography
    axial planeMinor axial plane of isoclinal and open folds, outcrop and suboutcrop scale
    beddingFault, measurement from major fault in contacts table
    faultFault, measurement from major fault in contacts table
    fold axisMinor fold axis, outcrop and suboutcrop scale
    foliationFoliation
    h beddingHorizontal bedding
    h foliationHorizontal foliation
    obs folFoliation observed from a distance, STATIONNO is the station from which the observation was made
    v faultVertical fault
    v foliationVertical foliation

    TREND
    Angle of strike or trend. strike and dip recorded using "right-hand rule"; trend recorded in horizontal plane of dip-direction (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:359
    Units:degrees

    DIP
    Dip or plunge (if known). Strike and dip recorded using "right-hand rule". Fold axis with "0" degree dip means dip was not measured. (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:90
    Units:degrees

    subsurfacepluton.shp
    Polyline showing extent of subsurface pluton as determined by the presence of hornfels, intrusions, alteration, and aeromagnetic highs (Burns and others, 2002). Table contains 7 objects, table contains no attributes (Source: Alaska Division of Geological & Geophysical Surveys)

    subsurfaceplutonsymbol.shp
    Point locations related to the subsurface pluton, table contains 2 objects (Source: Alaska Division of Geological & Geophysical Surveys)

    TEXTSTRING
    Point locations for query symbols (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    pluton queriedLocation or continuation of subsurface pluton trace is unknown

    xsection.shp
    Polyline trace of the cross section, table contains 1 object (Source: Alaska Division of Geological & Geophysical Surveys)

    NAME
    Name of the cross section (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    AA'Cross section A to A'


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?

    This project is part of the Alaska Airborne Geophysical/Geological Mineral Inventory Program funded by the Alaska State Legislature and managed by State of Alaska, Department of Natural Resources (DNR), Division of Geological & Geophysical Surveys (DGGS). Partial funding for the geologic mapping, geochronologic dates, and geochemical analyses performed for this project was also provided through the U.S. Geological Survey STATEMAP Program under award number 05HQAG0025 and the State of Alaska's General Fund. Coal energy analyses were provided by the federal National Coal Resource Database System.

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


Why was the data set created?

The Liberty Bell bedrock geologic map was produced from field work in 2005 by mineral-resource personnel from the Alaska Division of Geological & Geophysical Surveys and the University of Alaska Fairbanks. The purpose of the project is to provide 1:50,000-scale geologic mapping of a portion of the Liberty Bell airborne geophysical survey area. The helicopter-based survey included aeromagnetic and electromagnetic data which were released by DGGS in 2002. The geophysical survey and geologic mapping are part of the Alaska Airborne Geophysical/Geological Mineral Inventory Program, a special multi-year investment by the State of Alaska to expand Alaska's geologic and mineral resources knowledge base, catalyze future private-sector mineral exploration and development, and guide state planning.


How was the data set created?

  1. From what previous works were the data drawn?

    Burns and others, 2002 (source 1 of 11)
    Burns, L.E., Surveys, Fugro Airborne , and Stevens Exploration Management Corp., 2002, Plot files of the airborne geophysical survey data of the Liberty Bell area, western Bonnifield mining district, central Alaska: Geophysical Report GPR 2002-6, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 CD-ROM
    Type_of_Source_Media: CD-ROM
    Source_Contribution:
    The geophysical datasets in this publication were used throughout the Liberty Bell mapping project. Prior to field work, the geophysical data were used to identify locations of geophysically inferred faults and potential unit boundary locations. Unusual anomalies were noted for follow-up investigation in the field. Printed copies of the geophysical data, overlain by topography, were carried by geologists in the field to help determine the geologic cause for variations in the geophysical data along their traverses. During map compilation, geophysical data were useful for extending mapped contacts and faults through regions covered by vegetation or surficial deposits.

    Athey and others, 2005 (source 2 of 11)
    Athey, J.E., Werdon, M.B., Newberry, R.J., Szumigala, D.J., Freeman, L.K., and Lessard, R.R., 2005, Major-oxide, minor-oxide, and trace-element geochemical data from rocks collected in the Liberty Bell area, Fairbanks A-4 Quadrangle, Alaska in 2005: Raw Data File RDF 2005-5, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 29 pp.
    Type_of_Source_Media: paper
    Source_Contribution:
    This report contains major-oxide, minor-oxide, and trace-element geochemical data from rocks collected by DGGS in the Liberty Bell area. These data are used to suggest possible protoliths of metamorphosed and altered rocks, identify types of alteration, and assign trace-element indicated tectonic settings to igneous and meta-igneous rocks. Ore element geochemistry is used to evaluate the mineral-resource potential of the Liberty Bell area.

    Dusel-Bacon and others, 2004 (source 3 of 11)
    Dusel-Bacon, Cynthia, Wooden, J.L., and Hopkins, M.J., 2004, U-Pb zircon and geochemical evidence for bimodal mid-Paleozoic magmatism and syngenetic base-metal mineralization in the Yukon-Tanana terrane, Alaska: Geological Society of America Bulletin v. 116, n. 7, Geological Society of America, Boulder, CO, USA.

    Other_Citation_Details: p. 989-1015
    Type_of_Source_Media: paper
    Source_Contribution:
    This publication contains age and geochemical data for samples from the Devonian Totatlanika Schist and Keevy Peak Formation.

    Freeman and others, 1987 (source 4 of 11)
    Freeman, L.K., Hanneman, N.L., and Flanders, R.W., 1987, Liberty Bell Joint Venture Report of 1987 Exploration.

    Type_of_Source_Media: paper
    Source_Contribution:
    This RAA company report contains a geologic description of the Liberty Bell property, geologic maps, and geochemical data. These data were used to supplement DGGS mapping and interpretations. Geologic detail and structural measurements in the immediate mine area (inset map) are largely from 1:2,400-scale RAA mapping.

    Leopold and Liu, 1994 (source 5 of 11)
    Leopold, E.B., and Liu, Gengwu, 1994, A long pollen sequence of Neogene age, Alaska Range: Quaternary International v. 22/23.

    Other_Citation_Details: p. 103-140
    Type_of_Source_Media: paper
    Source_Contribution:
    This publication contains pollen sample data and environmental interpretations for the Usibelli Group and Nenana Gravel. These data were compared to pollen counts from this study.

    Ridgway and others, 1999 (source 6 of 11)
    Ridgway, K.D., Trop, J.M., and Jones, D.E., 1999, Petrology and provenance of the Neogene Usibelli Group and Nenana Gravel: Implications for the denudation history of the central Alaska Range: Journal of Sedimentary Research v. 69, no. 6.

    Other_Citation_Details: p. 1262-1275
    Type_of_Source_Media: paper
    Source_Contribution:
    This report contains multiple data types and interpretations (pollen, composition, provenance, paleocurrent directions, etc.) for the Suntrana Creek section of the Usibelli Group and Nenana Gravel. These data were compared to data from this study.

    Triplehorn, 1976 (source 7 of 11)
    Triplehorn, D.M., 1976, Clay mineralogy and petrology of the coal-bearing group near Healy: Geologic Report GR 52, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Other_Citation_Details: 14 pp.
    Type_of_Source_Media: paper
    Source_Contribution:
    This report contains clay compositions for the Usibelli Group formations in Suntrana Creek. Clay compositions from the study area were compared to these data.

    Wahrhaftig, 1970 (source 8 of 11)
    Wahrhaftig, Clyde, 1970, Geologic Map of the Fairbanks A-4 Quadrangle, Alaska: Geologic Quadrangle Map GQ-810.

    Other_Citation_Details: 1 sheet
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution:
    This map contains the only published detailed bedrock geology that covers the study area. This map was used as a reference for the geology and unit descriptions.

    Wahrhaftig, 1968 (source 9 of 11)
    Wahrhaftig, Clyde, 1968, Schists of the central Alaska Range: Bulletin B 1254-E.

    Other_Citation_Details: 22 pp.
    Type_of_Source_Media: paper
    Source_Contribution:
    This publication contains descriptions of the Devonian Totatlanika Schist and Keevy Peak Formation. Rocks in the study area were compared to these descriptions.

    Wahrhaftig and others, 1969 (source 10 of 11)
    Wahrhaftig, Clyde, Wolfe, J.A., Leopold, E.B., and Lanphere, M.A., 1969, The coal-bearing group in the Nenana Coal Field, Alaska: Bulletin B 1274-D.

    Other_Citation_Details: p. D1-D30
    Type_of_Source_Media: paper
    Source_Contribution:
    This publication contains information (composition, paleocurrent directions, pollen, etc.) for the Tertiary Usibelli Group and Nenana Gravel in the Nenana Coal Field. This information was used to interpret data generated from this study and compare data between other areas of the Nenana Coal Field.

    Yesilyurt, 1996 (source 11 of 11)
    Yesilyurt, Suleyman, 1996, Geology, geochemistry, and mineralization of the Liberty Bell gold mine area, Alaska:.

    Other_Citation_Details: p. 1281-1316.
    This is part of the following larger work.

    (ed.), A.R. Coyner , and (ed.), P.L. Fahey , 1996, Geology and Ore Deposits of the American Cordillera: Symposium Proceedings: Geological Society of Nevada, Reno/Sparks, Nevada.

    Other_Citation_Details: April 1995
    Type_of_Source_Media: paper
    Source_Contribution:
    This report contains detailed information about mineralization and alteration at the Liberty Bell Mine. It also contains age data and compositional data. This information was used to supplement DGGS data related to Liberty Bell mineralization.

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

    Date: 2005 (process 1 of 3)
    Field work - During the summer of 2005 DGGS conducted a three-week field mapping project to provide geologic ground truth for an airborne geophysical survey flown in the Liberty Bell area in 2001 (Burns and others, 2002). DGGS efforts are focused on determining the geologic framework of the Liberty Bell area, and its potential for hosting lode mineral deposits. Field work for bedrock investigations, including ridge traverses and examination of riverbank exposures, was conducted for approximately 105 person-days during July 2005. Field notes and rock samples were collected at approximately 1,405 stations throughout the southern Fairbanks A-4 Quadrangle. Plots of an orthorectified air photo mosaic were used to find outcrops in the field and identify linear features that may have geologic significance. Plots of airborne magnetic and resistivity data (Burns and others, 2002) overlain with standard USGS raster topography were used daily in the field to help identify geologic contacts, units, and faults. At most field stations, magnetic susceptibility data were collected to help identify magnetic units. Bedrock mappers recorded observations on 1:50,000-scale topographic base maps of 15-minute quadrangles that were enlarged from a scale of 1:63,360. In the evenings, each geologist's observations were compiled onto a single Mylar base map. Field stations were located using handheld Garmin 12XL GPS units. Field station notes and downloaded GPS location data were entered into a Microsoft Access 2000 database.

    Data sources used in this process:

    • Burns and others, 2002
    • U.S. Geological Survey, Digital Raster Graphic (DRG), Fairbanks A-4

    Date: 2006 (process 2 of 3)
    Laboratory data - Paleozoic rocks and younger, unmetamorphosed igneous rocks were primarily defined by chemical composition, examination of hand samples, and petrography. Approximately 280 samples were analyzed for major-and minor-oxide and trace elements by a commercial analytical laboratory (Athey and others, 2005) and the University of Alaska Fairbanks (RI 2006-2 text, appendix A). These data are used to suggest possible protoliths of metamorphosed and altered rocks, identify types of alteration, and assign trace-element indicated tectonic settings to igneous and meta-igneous rocks. Unit descriptions are also based on the petrographic examination and modal analysis of 169 thin sections. Six 40Ar/39Ar ages (RI 2006-2 text, table 5; appendix B) were used to constrain timing of igneous events, mineralization, and metamorphism in the Liberty Bell Mine area. (Liberty Bell Mine area is defined as the western, rounded portion of the area outlined on sheet RI 2006-2 as underlain by the subsurface pluton [see "Map Symbols"]; area is outlined in figure "Location Map of the Liberty Bell Mine area and hill VABM Coal" on sheet RI 2006-2. The area coincides with a donut-shaped, aeromagnetic high [Burns and others, 2002]). Tertiary units were differentiated by a combination of sand grain composition, clay composition, and palynology. Sixty grain mounts of Tertiary sand were point-counted (RI 2006-2 text, appendix C) in order to compare sand composition. Clay compositions were determined by X-ray diffraction for sixty-five samples of unconsolidated rock (RI 2006-2 text, appendix D). Pollen was identified and counted in fifteen samples of fine-grained Tertiary sedimentary rock and coal (RI 2006-2 text, appendix E). To evaluate the mineral-resource potential of the Liberty Bell area, 116 samples of visibly mineralized rock, or rock exhibiting features associated with mineralization, were analyzed for geochemical trace elements (Athey and others, 2005). To evaluate the energy-resource potential of the Liberty Bell area, twenty-one coal samples were analyzed for energy values (proximate and ultimate analyses, BTU, etc.) and trace-elements of their ash (RI 2006-2 text, appendix F). The composition of a placer gold sample was determined by X-ray fluorescence (RI 2006-2 text, table 6).

    Data sources used in this process:

    • Athey and others, 2005
    • Burns and others, 2002

    Date: 2006 (process 3 of 3)
    Digital Cartography - The final compilation of the bedrock geologic map data on Mylar and the RAA Liberty Bell Mine map (Freeman and others, 1987) were scanned as high-resolution tiff files. The files were imported into MapInfo Professional 8.0, and geographically registered in UTM coordinates (see spatial reference information section below). Geologic unit polygons were digitized 'on-screen' by tracing geologic contacts; each polygon was attributed with appropriate supporting information. The geologic polygon and polyline layers were imported into ArcGIS 9.1 geodatabase format using ArcCatalog 9.1. Spatially registered point data for the map were made in MapInfo Professional 8.0 from Microsoft Excel and Access 2000 files and converted into ArcGIS 9.1 geodatabase format using ArcCatalog 9.1. Editing and quality control checks took place at every process step. Final geologic feature and attribute editing was completed in ArcGIS 9.1. Map text was created in Microsoft Word 2000. Final map layout, editing, and printing were accomplished using CorelDRAW 10.0.

    Data sources used in this process:

    • U.S. Geological Survey, Digital Raster Graphic (DRG), Fairbanks A-4
    • Freeman and others, 1987

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

    Athey, J.E., Werdon, M.B., Newberry, R.J., Szumigala, D.J., Freeman, L.K., and Lessard, R.R., 2005, Major-oxide, minor-oxide, and trace-element geochemical data from rocks collected in the Liberty Bell area, Fairbanks A-4 Quadrangle, Alaska in 2005: Raw Data File RDF 2005-5, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 29 pp.
    Burns, L.E., Surveys, Fugro Airborne , and Stevens Exploration Management Corp., 2002, Plot files of the airborne geophysical survey data of the Liberty Bell area, western Bonnifield mining district, central Alaska: Geophysical Report GPR 2002-6, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 CD-ROM
    Wahrhaftig, Clyde, 1970, Geologic Map of the Fairbanks A-4 Quadrangle, Alaska: Geologic Quadrangle Map GQ-810, U.S. Geological Survey, Washington, DC, USA.

    Other_Citation_Details: 1 sheet, scale 1:63,360


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

  1. How well have the observations been checked?

    Location data for geologic point data sets were downloaded from Garmin 12XL GPS units into a Microsoft Access database. Field notes were manually entered into the database. Spatial data attributes were either queried directly from the database or attached to the objects using MapInfo Professional 7.5 and ArcGIS 9.1. Attributes were verified for consistency and completeness during the creation of the metadata. Geologic data used in the compilation are the field maps and notes from this project as well as data from other sources as noted in the "Source_Information" section.

  2. How accurate are the geographic locations?

    DGGS location data and estimated position errors were downloaded from Garmin 12XL GPS units into an Access database. Sample numbers and locations with selected data were queried from the database or brought into an Excel spreadsheet and then spatially registered and analyzed in MapInfo Professional 7.5 and 8.0. The horizontal positional accuracies of field stations not measured by DGGS are unknown, but methodology presumably varies widely from precise local grid measurements (~20 m error) to less accurate topography and altimeter-style mapping (~100 m error).

  3. How accurate are the heights or depths?

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

    This dataset includes information about geologic units, age sample locations, structural features, structural measurements, dike locations, hornfels locations, pollen sample locations, and coal sample locations.

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

    Topology is present on appropriate polygon and line data sets; others are point data sets.


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 hardcopies 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.

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

    State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
    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.dnr.state.ak.us>) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
  2. What's the catalog number I need to order this data set?

    Report of Investigation 2006-2

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

    Please check the MapInfo web site (<http://www.mapinfo.com/>) for the latest documentation on importing ESRI shape files.


Who wrote the metadata?

Dates:
Last modified: 06-May-2008
Last Reviewed: 06-May-2008
To be reviewed: 15-Feb-2009
Metadata author:
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
c/o Jennifer Athey
DGGS Minerals Section Geologist
3354 College Road
Fairbanks, AK 99709-3707
USA

907-451-5010 (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 Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.9.6 on Tue May 06 14:29:39 2008