Surficial-Geologic Map of the Eagle A-2 Quadrangle, Fortymile mining district, Alaska

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Frequently-anticipated questions:


What does this data set describe?

Title:
Surficial-Geologic Map of the Eagle A-2 Quadrangle, Fortymile mining district, Alaska
Abstract:
The Alaska Division of Geological & Geophysical Surveys (DGGS) has conducted 1:63,360-scale geologic mapping of the Eagle A-2 Quadrangle (270 square miles; equivalent to four 7.5-minute quadrangles). The area is part of the 100-year old Fortymile mining district and is located in eastern Alaska near the Alaska-Yukon border. This map illustrates the distribution of a variety of unconsolidated deposits and undifferentiated bedrock in the Eagle A-2 Quadrangle, Fortymile mining district. It was prepared by the interpretation of 1:63,360-scale, false-color, infrared aerial photographs taken from July 1978 through August 1981 and is locally verified by ground observations during field visits. The results should be considered reconnaissance in nature. The dominant unconsolidated deposit is colluvium, which mantles most surfaces other than the tops of ridges and those areas immediately adjacent to streams. Three levels of stream terrace can be traced along major drainages at elevations of roughly 200, 100, and 30 meters above modern streams. A fourth low terrace is limited to the southwest part of the map area. Pleistocene mammalian remains have been recovered from ice-rich organic silt and muck overlying placer gravels in many valleys.
Supplemental_Information:
The layers listed below are present as ArcGIS shape files. Attribute information for the following 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 "Entity_Type_Label." Basic unit information is also included in the unit code set file "PIR2001-3_codeset.pdf." Layers include:
fmpingos     pingo locations
fmsurfgeo2     surficial geologic units
  1. How should this data set be cited?

    Pinney, D.S., 200105, Surficial-Geologic Map of the Eagle A-2 Quadrangle, Fortymile mining district, Alaska: Preliminary Interpretive Report PIR 2001-3C, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:63,360

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -142.00902346
    East_Bounding_Coordinate: -141.49552824
    North_Bounding_Coordinate: 64.25256429
    South_Bounding_Coordinate: 63.9974188

  3. What does it look like?

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

    Beginning_Date: 1999
    Ending_Date: 2001
    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: 7
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -141.000000
      Latitude_of_Projection_Origin: 0.000000
      False_Easting: 500000.000000
      False_Northing: 0.000000

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000205
      Ordinates (y-coordinates) are specified to the nearest 0.000205
      Planar coordinates are specified in Meters

      The horizontal datum used is D_Clarke_1866.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6,378,206.400000.
      The flattening of the ellipsoid used is 1/294.978698.

  7. How does the data set describe geographic features?

    fmsurfgeo2.shp
    Object type is vector, there are 1013 rows associated with this entity, and the entity values refer to surficial geologic units (Source: Alaska Division of Geological & Geophysical Surveys)

    TEMP
    This meaning of this attribute is unknown. (Source: Alaska Division of Geological & Geophysical Surveys)

    The description is not from any specific domain

    UNIT
    surficial geologic unit labels, any unit ending with a "?" indicates uncertainty (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    lakepolygons defining a lake

    Formal codeset
    Codeset Name:PIR2001-3_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys

    SUNIT
    surficial geologic unit labels, any unit ending with a "?" indicates uncertainty (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    lakepolygons defining a lake

    Formal codeset
    Codeset Name:PIR2001-3_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys

    SURFBED
    what portions of contacts are under surficial cover as opposed to exposed bedrock (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Ssurficial deposit
    Bbedrock deposit

    JUSTBED
    quaternary and generalized bedrock unit labels (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    BXbedrock

    Formal codeset
    Codeset Name:PIR2001-3_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys

    fmpingos.shp
    Object type is point, there are 2 rows associated with this entity, and the entity values refer to pingo locations (Source: Alaska Division of Geological & Geophysical Surveys)

    TEMP
    attribute describing the object pingo (Source: Alaska Division of Geological & Geophysical Surveys)

    The description is not from any specific domain

    UNIT
    attribute describing the object pingo (Source: Alaska Division of Geological & Geophysical Surveys)

    The description is not from any specific domain

    SUNIT
    attribute describing the object pingo (Source: Alaska Division of Geological & Geophysical Surveys)

    The description is not from any specific domain

    SURFBED
    what portions of contacts are under surficial cover as opposed to exposed bedrock (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    SFluvial and glaciofluvial gravel, sand, and silt. Chiefly (estimated >80 percent) clean sand and gravel. Grain size, sorting and degree of stratification are variable.


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 was also provided by the U.S. Geological Survey, National Cooperative Geologic Mapping Program, under STATEMAP award number 00HQAG0071 under the NCGM STATEMAP program for FY2000. 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?

    State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
    GIS Data Manager/Cartographer
    3354 College Road
    Fairbanks, AK 99709-3707

    (907) 451-5029 (voice)
    (907) 451-5050 (FAX)
    dggspubs@alaska.gov

    Contact_Instructions:
    You may view our web site at <http://www.dggs.dnr.state.ak.us> for the latest information on available data. Please e-mail your questions and data requests when possible since our web site and e-mail address will remain current even if our phone number and mailing address change.


Why was the data set created?

This project, resulting map, geospatial data are intended to provide a geologic map and a geologic interpretation of the Fortymile mining district at 1:63,360 scale. Previous published 1:63,360 scale geologic maps of this area have been reconnaissance-level maps or only covered portions of the quadrangle. Mapping at 1:63,360 scale (or more detailed) is needed to identify critical geologic features that may relate to more regional structures or geologic units. These detailed observations are also critical to test or use in tectonic models. This map also provides a geologic base in which to interpret geochemical results from the concurrent DGGS rock sampling program.


How was the data set created?

  1. From what previous works were the data drawn?

    Naeser and others, 1982 (source 1 of 3)
    Naeser, N.D., Westgate, J.A., Hughes, O.L., and Pewe, T.L., 1982, Fission-track ages of late Cenozoic distal tephra beds in the Yukon Territory and Alaska: Canadian Journal of Earth Sciences Vol. 19, Canadian Journal of Earth Sciences, Canada.

    Other_Citation_Details: p. 2167-2178
    Type_of_Source_Media: paper
    Source_Contribution: See this publication cited in the Process Step section below

    Yeend, 1996 (source 2 of 3)
    Yeend, Warren, 1996, Gold placers of the historical Fortymile River region, Alaska: U.S. Geological Survey Bulletin 2125, United States Government Printing Office, Washington D.C., Maryland.

    Other_Citation_Details: 74 p., 1 sheet
    Type_of_Source_Media: paper
    Source_Contribution: See this publication cited in the Process Step section below

    Werdon and others, 2001 (source 3 of 3)
    Werdon, M.B., Newberry, R.J., and Szumigala, D.J., 2001, Geologic map of the Eagle A-1 Quadrangle, Fortymile mining district, Alaska: Preliminary Interpretive Report PIR 2001-3A, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 1 sheet
    Type_of_Source_Media: paper, online, CD-ROM
    Source_Contribution: See this publication cited in the Process Step section below

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

    Date: 2000 (process 1 of 3)
    Fieldwork- Fieldwork for surficial investigations, including traverses, road cut investigations, and river exposures, was conducted for 50 person-days during the months of June through August in 1999 and 2000. Field notes and sediment samples were collected throughout the quadrangle for surficial investigations. Surficial mapping involved using Yeend (1996) on a regular basis for checking placer geology and general units. Surficial mappers recorded observations on 1:50,000 scale (nominal) color-infrared aerial photographs and 1:63,360 scale topographic base maps. Stations located using air photos and hand held GPS devices with location precision varying from +/-3 to 15 meters.

    Data sources used in this process:

    • Yeend, 1996

    Date: 2000 (process 2 of 3)
    Laboratory data compilation- Laboratory analyses were performed on radiocarbon samples and gold-bearing gravel samples from June 1999 intermittently through April 2001. Unanalyzed radiocarbon and tephra samples are currently stored at the DGGS office in Fairbanks. Final storage for most samples generated by this study will be at the DGGS Geologic Material Center (GMC) in Eagle River, Alaska.

    Date: 2000 (process 3 of 3)
    Geologic map compilation- Surficial geologic map was compiled using field notes from fieldwork process step (above), analytical results from laboratory data compilation process step (above), and all known geologic data from previous work in quadrangle. The main sources of existing data include Yeend (1996), Naeser and others (1982), and Werdon and others (2001). Geologic map contacts were delineated by photo interpretation of 1:50,000-scale color-infrared aerial photographs onto clear acetate overlays. The contacts were transferred from the overlays onto paper USGS 1:63,360 topographic base maps using a zoom transfer scope, and the contacts were then digitized using ArcEdit. Line work was edited using ArcEdit, and polygon topology generated and unit designations assigned using ArcInfo and ArcEdit. ArcPlot was used to generate plot files using DGGS-standard symbology, and the Arc graphics files were converted into .eps files for export to Adobe Illustrator for final cartographic assembly.

    Data sources used in this process:

    • Naeser and others, 1982
    • Werdon and others, 2001
    • Yeend, 1996

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

    Werdon, M.B., Newberry, R.J., Szumigala, D.J., and Pinney, D.S., 200105, Geologic Map of the Eagle A-2 Quadrangle, Fortymile mining district, Alaska: Preliminary Interpretive Report PIR 2001-3A, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (DGGS), Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:63,360
    Werdon, M.B., Newberry, R.J., and Szumigala, D.J., 200105, Geologic Map of the Eagle A-2 Quadrangle, Fortymile mining district, Alaska 2001: Preliminary Interpretive Report PIR 2001-3B, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:63,360
    Pinney, D.S., 200105, Engineering-geologic Map of the Eagle A-2 Quadrangle, Fortymile mining district, Alaska 2001: Preliminary Interpretive Report PIR 2001-3D, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:63,360
    Yeend, Warren, 1996, Gold placers of the historical Fortymile River region, Alaska: U.S. Geological Survey Bulletin 2125, United States Government Printing Office, Washington D.C., Maryland.

    Other_Citation_Details: 74 p., 1 sheet


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

  1. How well have the observations been checked?

    This compilation for the surficial geologic information was done on a one-to-one scale, paper map of the USGS topographic base for each of the 1:63,360 scale USGS topographic bases included in the map area. Geologic data included in the compilation are the field maps and notes from this project as well as photo interpretation of 1:50,000 (nominal) scale color-infrared aerial photographs and data from other sources as noted in the "Sources Cited" section.

  2. How accurate are the geographic locations?

    Surficial mappers recorded observations on 1:50,000 scale (nominal) color-infrared aerial photographs and 1:63,360 scale topographic base maps.

  3. How accurate are the heights or depths?

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

    This data set includes geospatial data about geologic units, age and pingo locations.

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

    Polygon topology present. Polygon topology present on appropriate data; others are line, point, or annotation data and do not require topologic relationships.


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.

  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?

    Preliminary Interpretive Report 2001-3C

  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: 05-Jan-2009
Metadata author:
State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys
Metadata Manager
3354 College Road
Fairbanks, AK 99709-3707
USA

907-451-5039 (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 14:29:36 2008