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

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Frequently anticipated questions:


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 v. 1.0.1, Bedrock geologic map of the Liberty Bell area, Fairbanks A-4 Quadrangle, Bonnifield mining district, Alaska, provides 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. The complete report, geodatabase, and ESRI fonts and style files are available from the DGGS website: http://doi.org/10.14509/15026.
Supplemental_Information:
This geodatabase is organized according to the AK GeMS mapping schema Hendricks, M.D., Ekberg, P.G., Athey, J.E., Wyatt, W.C., Willingham, A.L., and Naibert, T.J., 2021, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 170, 10 p. https://doi.org/10.14509/30669. The distribution package includes ESRI fonts and style files, along with usage instructions. Further documentation of the symbology is provided by Ekberg, P.G., Hendricks, M.D., and Athey, J.E., 2021, AK GeMS symbology: A description of the AK GeMS style file: Alaska Division of Geological & Geophysical Surveys Miscellaneous Publication 169, 7 p. https://doi.org/10.14509/30584
  1. How might 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, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 98 p., 1 sheet, scale 1:50,000
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -149.008974
    East_Bounding_Coordinate: -148.493298
    North_Bounding_Coordinate: 64.131002
    South_Bounding_Coordinate: 63.993979
  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:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: geodatabase
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a vector data set.
    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
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.000000
      False_Northing: 0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest .00000001
      Ordinates (y-coordinates) are specified to the nearest .00000001
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD27.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.40000000037.
      The flattening of the ellipsoid used is 1/294.978698199999997.
  7. How does the data set describe geographic features?
    liberty_bell_bedrock_ak_gems_db_pkg
    Geodatabase, layer files, style files, and fonts (Source: Alaska Division of Geological & Geophysical Surveys)
    liberty_bell_bedrock_gems_db_pkg
    Geodatabase, layer files, style files, and fonts (Source: Alaska Division of Geological & Geophysical Surveys)
    liberty_bell_bedrock_gems_shapefile_pkg
    Shapefiles and open data files (Source: Alaska Division of Geological & Geophysical Surveys)

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. Geologic map conversion to the GeMS standard was funded by the USGS National Cooperative Geologic Mapping Program under StateMap award number G20AC00367, 2020, and the State of Alaska General Fund. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.
  3. To whom should users address questions about the data?
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    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 website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.

Why was the data set created?

The geologic map of the Liberty Bell mine area provides 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?
    Athey, J.E. and others, 2005 (source 1 of 5)
    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, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 29 p
    Type_of_Source_Media: paper
    Source_Contribution: Laboratory data compilation
    Ekberg, P.G. and others, 2021 (source 2 of 5)
    Ekberg, P.G., Hendricks, M.D., and Athey, J.E., 2021, AK GeMS symbology: A description of the AK GeMS style file: Miscellaneous Publication MP 169, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 7 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
    Fugro Airborne Surveys and others, 2018 (source 3 of 5)
    Surveys, Fugro Airborne, Stevens Exploration Management Corp., Burns, L.E., and Graham, G.R.C., 2018, Electromagnetic and magnetic airborne-geophysical survey of the Liberty Bell area, western Bonnifield mining district, Alaska (data compilation): Geophysical Report GPR 2018-10, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 12 p
    Type_of_Source_Media: paper
    Source_Contribution: Geologic mapping
    Hendricks, M.D. and others, 2021 (source 4 of 5)
    Hendricks, M.D., Ekberg, P.G., Athey, J.E., Wyatt, W.C., Willingham, A.L., and Naibert, T.J., 2021, AK GeMS data dictionary: A description of the Alaska geologic mapping schema: Miscellaneous Publication MP 170, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
    U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020 (source 5 of 5)
    U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020, GeMS (Geologic Map Schema) - A standard format for the digital publication of geologic maps: Techniques and Methods TM 11-B10, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 1 p
    Type_of_Source_Media: paper
    Source_Contribution: GIS analysis and digital cartography
  2. How were the data generated, processed, and modified?
    Date: 2005 (process 1 of 4)
    Geologic mapping - 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. Fieldwork 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. Data sources used in this process:
    • Fugro Airborne Surveys and others, 2018
    Date: 2005 (process 2 of 4)
    Laboratory data compilation - 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 and the University of Alaska Fairbanks. 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 were used to constrain timing of igneous events, mineralization, and metamorphism in the Liberty Bell Mine area. The area coincides with a donut-shaped, aeromagnetic high. Tertiary units were differentiated by a combination of sand grain composition, clay composition, and palynology. Sixty grain mounts of Tertiary sand were point-counted in order to compare sand composition. Clay compositions were determined by X-ray diffraction for sixty-five samples of unconsolidated rock. Pollen was identified and counted in fifteen samples of fine-grained Tertiary sedimentary rock and coal. 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. 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. The composition of a placer gold sample was determined by X-ray fluorescence. Data sources used in this process:
    • Athey, J.E. and others, 2005
    Date: 2006 (process 3 of 4)
    Geologic map compilation - The conceptual framework for the regional geology incorporates key ideas from preexisting literature. A comprehensive bibliographic reference list of prior work used to identify and delineate rock units and structural elements is provided in the accompanying report. The map and report received technical review and editing by several scientists familiar with the subject matter. The authors incorporated the reviewers' suggestions into the final draft.
    Date: 2022 (process 4 of 4)
    GIS analysis and digital cartography - This data distribution package's geologic and geographic features were organized and attributed according to the AK GeMS geologic mapping schema. The data were then programmatically transformed to provide download options in three formats: (1) an AK GeMS data package that includes the complete AK GeMS database and associated files, (2) a GeMS data package that is a conversion of the AK GeMS database into the base GeMS standard published by the USGS, and (3) a shapefile data package that includes two simple shapefile representations of the data. Data sources used in this process:
    • Ekberg, P.G. and others, 2021
    • Hendricks, M.D. and others, 2021
    • U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020
  3. What similar or related data should the user be aware of?
    Staff, DGGS, and Athey, J.E., 2006, Alaska GeoSurvey News - Geologic ground-truth inventory Liberty Bell, western Bonnifield mining district geophysical tract: Newsletter NL 2006-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p

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

  1. How well have the observations been checked?
    This data release provides legacy geospatial data converted to the GeMS and AK GeMS specifications. Attribute fields within each feature class are populated using corresponding applicable values from the GeMS and AK GeMS specifications. When known, certainty in attribute interpretation is indicated in the relevant fields. Attribute accuracy varies throughout the map and is scale-dependent.
  2. How accurate are the geographic locations?
    This data release provides legacy geospatial data converted to the GeMS and AK GeMS specifications. The data include descriptive fields within each feature class and accompanying orientation and location confidence lookup tables to record the originating authors' degree of confidence in the location of features. Certainty in feature boundaries or location varies throughout the map.
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
    This publication is part of a DGGS Report of Investigations (RI). An RI is the completed product of original research and analysis, and RIs use professional cartography and undergo rigorous peer review, editing, and revision.
  5. How consistent are the relationships among the observations, including topology?
    All polygon features were topologically validated according to the AK GeMS geologic mapping schema specifications.

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 is 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. The 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. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data 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 or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  1. Who distributes the data set? (Distributor 1 of 1)
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    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 website (https://www.dggs.alaska.gov) 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? RI 2006-2 v. 1.0.1
  3. What legal disclaimers am I supposed to read?
    The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data 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 or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 22-Mar-2022
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Attn: Simone Montayne
Metadata Manager
3354 College Road
Fairbanks, AK
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
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.50 on Mon Mar 21 17:15:18 2022