Geologic map of the Eagle A-1 Quadrangle, Fortymile mining district

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What does this data set describe?

Title:
Geologic map of the Eagle A-1 Quadrangle, Fortymile mining district
Abstract:
This geologic map was produced by merging a bedrock geologic map and a surficial geologic map of the Eagle A-1 Quadrangle. Surficial geologic units were determined by a combination of air photo interpretation and site-specific field investigations. Bedrock geologic units were determined by using a combination of airborne magnetic and electromagnetic surveys, several months of fieldwork, geochemical data, and laboratory investigations. These maps are the result of new field investigations by DGGS in 1999 and 2001.
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 "PIR2002-1_codeset.pdf." Layers include:
eaga1ages_2     age date locations
eaga1bedcont2     bedrock unit contact boundaries
eaga1compdike     dike strike orientations
eaga1compfld2     axial traces
eaga1compflt2     fault traces
eaga1compgeo3     uncoded contacts surrounding the surficial and bedrock units
eaga1compshr     uncoded contacts surrounding the exposed sheared bedrock units
eaga1dikes     dike composition and location
eaga1faultsym     fault orientation
eaga1foldsym     fold orientation
eaga1indmin     kyanite, staurolite, and tourmaline localities identified by thin section petrography
eaga1pingo     pingo locations
eaga1srfcont     contacts surrounding the surficial units
eaga1str     foliation and bedding structural information
  1. How should this data set be cited?

    Szumigala, D.J., Newberry, R.J., Werdon, M.B., Athey, J.E., Stevens, D.S.P., Flynn, R.L., Clautice, K.H., and Craw, P.A., 2002, Geologic map of the Eagle A-1 Quadrangle, Fortymile mining district: Preliminary Interpretive Report PIR 2002-1A.

    Online Links:

    Other_Citation_Details: 1 sheet, scale 1:63,360, 6 disks

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -141.504512
    East_Bounding_Coordinate: -141.000000
    North_Bounding_Coordinate: 64.250853
    South_Bounding_Coordinate: 63.999139

  3. What does it look like?

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

    Beginning_Date: 1999
    Ending_Date: 2002
    Currentness_Reference: publication date

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

    Geospatial_Data_Presentation_Form: map, 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: 0.9996
      Longitude_of_Central_Meridian: -141.000
      Latitude_of_Projection_Origin: 0.0
      False_Easting: 500000
      False_Northing: 0.0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000032
      Ordinates (y-coordinates) are specified to the nearest 0.000032
      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?

    eaga1ages_2.shp
    Point attribute table of age date locations (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPLE_NO
    Unique sample identifier (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    Generic example of unique sample identifier: YYAAA999X: YY=last two digits of year, AAA=geologist's initials (one to three characters), 999=unique station number, X=null or unique alpha character designating a sample was taken at the field station

    DATE
    Date sample was collected in the field. Date is only known for samples collected by Alaska Division of Geological & Geophysical Surveys. Date is in MM/DD/YY format. (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    Range of values
    Minimum:6/7/2000
    Maximum:8/27/2000
    Units:MM/DD/YY date

    EASTING
    Easting (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:478000
    Maximum:499904
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7101973
    Maximum:7120500
    Units:meters

    Lithology
    Brief description of samples (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    sample descriptions

    SYMBOL
    Symbol identifying age date location on maps PIR 2002-1A and PIR 2002-1B. (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    sample descriptions

    eaga1bedcont2.shp
    Attribute table of bedrock unit contacts. This attribute table is the final product of a merge between the bedrock geology and the surficial geology polygon coverages. This attribute table indicates whether a non-faulted bedrock contact will be visible or concealed underneath surficial deposits. (Source: Alaska Division of Geological & Geophysical Surveys)

    CODE
    line style coding of bedrock contacts, contact concealed where underneath surficial cover (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    0line not visible, faulted contact
    4bounding box
    7contact inferred
    9contact concealed

    SURFBED
    Indicates whether a particular line segment is or is not covered by surficial deposits (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Ssurficial, bedrock contact is covered by surficial deposits
    Bbedrock, bedrock contact is not covered by surficial deposits

    eaga1compdike.shp
    Attribute table of dike strike orientations. This attribute table is the final product of a merge between the bedrock dike strike orientations arc coverage and the surficial geology polygon coverage. This attribute table indicates whether a dike strike orientation arc segment would be visible or concealed underneath surficial deposits. (Source: Alaska Division of Geological & Geophysical Surveys)

    CODE
    line style coding of dike strike orientations (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    57Dikes

    SURFBED
    Indicates whether a particular line segment is or is not covered by surficial deposits (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Ssurficial, arc segment is covered by surficial deposits
    Bbedrock, arc segment is not covered by surficial deposits

    eaga1compfld2.shp
    Attribute table of axial traces. This attribute table is the final product of a merge between the bedrock axial traces arc coverage and the surficial geology polygon coverage. This attribute table indicates whether an axial trace will be visible or concealed underneath surficial deposits. (Source: Alaska Division of Geological & Geophysical Surveys)

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

    ValueDefinition
    antianticline
    synsyncline
    overantioverturned anticline
    oversynoverturned syncline

    CODE
    Line style coding of axial traces, trace concealed where underneath surficial cover (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    35anticline or syncline, approximately located
    38anticline or syncline, concealed

    SURFBED
    Indicates whether a particular line segment is or is not covered by surficial deposits (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Ssurficial, segment of axial trace is covered by surficial deposits
    Bbedrock, segment of axial trace is not covered by surficial deposits

    eaga1compflt2.shp
    Attribute table of fault traces. This attribute table is the final product of a merge between the bedrock fault traces arc coverage and the surficial geology polygon coverage. This attribute table indicates whether a fault trace will be visible or concealed underneath surficial deposits. (Source: Alaska Division of Geological & Geophysical Surveys)

    CODE
    Line style coding of fault traces, trace concealed where underneath surficial cover (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    12Fault, approximately located
    15Fault, concealed
    18Thrust fault, approximately located
    22Thrust fault, concealed

    SURFBED
    Indicates whether a particular line segment is or is not covered by surficial deposits (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Ssurficial, segment of fault trace is covered by surficial deposits
    Bbedrock, segment of fault trace is not covered by surficial deposits

    eaga1compgeo3.shp
    Attribute table of the surficial and bedrock units (Source: Alaska Division of Geological & Geophysical Surveys)

    UNIT
    bedrock and surficial map unit labels (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:PIR2002-1_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys

    MAT
    materials map unit labels (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:PIR2002-1_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys

    eaga1compshr.shp
    Polygon attribute table of sheared bedrock units (Source: Alaska Division of Geological & Geophysical Surveys)

    UNIT
    bedrock unit designator (Source: Alaska Division of Geological & Geophysical Surveys, PIR 2002-1a and PIR 2002-1b)

    ValueDefinition
    shr_Ts(sheared) SEDIMENTARY ROCKS (Tertiary) - Poorly- to well-indurated, nonmarine sedimentary rocks of Tertiary age, as established by pollen (Foster, 1976; Foster and Igarashi, 1990).
    shr_pMsg(sheared) SCHIST AND PARAGNEISS (Pre-Mississippian) Mixed unit characterized by abundant aluminous metasedimentary rocks.

    eaga1dikes.pat
    Point attribute table of dike composition and location (Source: Alaska Division of Geological & Geophysical Surveys)

    STATION
    Unique sample identifier (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    Generic example of unique sample identifier: YY(YY)AAA999X: YY=last two digits of year or complete 4 digit year, AAA=geologist’s initials (one to three characters), 999=unique station number, X=null or unique alpha character designating a sample was taken at the field station

    TYPE
    A number designating the composition of a dike (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    1Diabase, equivalent to eTd (Tertiary)
    6Aplitic to pegmatitic; interpreted to be the latest phase of Jurassic, equivalent to Jga intrusions (Jurassic)
    7Felsic to intermediate granitic; equivalent to Jurassic intrusions (Jurassic), equivalent to Jg
    11Foliated; may either be syn-Jurassic deformation, or part of the pre-Mississippian amphibolite-facies metamorphic rocks
    13Rhyolite, equivalent to lKf (Cretaceous)
    14Hornblendite; equivalent to Jh (Jurassic)
    16Basalt, equivalent to lTb (Tertiary)

    EASTING
    Easting (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:475893
    Maximum:498930
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7096891
    Maximum:7124037
    Units:meters

    eaga1faultsym.shp
    Point attribute table of fault orientation symbols (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol style coding of fault orientation (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    7Bearing of dip of fault

    eaga1foldsym.shp
    Point attribute table of fold orientation symbols (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol style coding of fold orientation (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    22Anticline
    23Syncline
    26Overturned syncline
    27Overturned anticline
    39Arrow indicating plunging direction of fold axis

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

    ValueDefinition
    antianticline
    synsyncline
    overantioverturned anticline
    oversynoverturned syncline

    eaga1indmin.shp
    Point attribute table of kyanite, staurolite, and tourmaline localities identified by thin section petrography (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPLE_NO
    Unique sample identifier (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    Generic example of unique sample identifier: (YY)YYAAA999X: (YY)YY=last two digits of year or complete 4 digit year, AAA=geologist’s initials (one to three characters), 999=unique station number, X=null or unique alpha character designating a sample was taken at the field station; some sample identifiers have “–M/DD” at the end of the identifier, which indicates the date the sample was collected

    EASTING
    Easting (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:475609
    Maximum:498703
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7098732
    Maximum:7123509
    Units:meters

    Mineral
    Indicator mineral that was identified by thin section petrography (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    kyanitekyanite
    staurolitestaurolite
    tourmalinetourmaline

    TYPE
    Symbol showing location on maps PIR 2002-1a and PIR 2002-1b of indicator minerals that were identified by thin section petrography. (Source: Alaska Division of Geological & Geophysical Surveys and others (see Source information))

    ValueDefinition
    Kkyanite
    Sstaurolite
    Ttourmaline

    eaga1pingo.shp
    Point attribute table of pingo locations (Source: Alaska Division of Geological & Geophysical Surveys)

    CODE
    Symbol style coding of pingo (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    52Pingo

    eaga1srfcont.shp
    Attribute table of the surficial units (Source: Alaska Division of Geological & Geophysical Surveys)

    JUSTBED
    surficial map unit labels, exposed bedrock areas designated as "BX" (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:PIR2002-1_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys

    eaga1str.shp
    Point attribute table of foliation and bedding structural information (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPLE_NO
    Unique sample identifier (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of unique sample identifier: YYYYAAA999X: YYYY=complete 4 digit year, AAA=geologist’s initials (one to three characters), 999=unique station number, X=null or unique alpha character designating a sample was taken at the field station

    YEAR
    Year the sample was collected (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:1999
    Maximum:2001
    Units:year

    GEOINI
    Initials of the geologist collecting the sample (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    DSDavid Szumigala
    JEAJennifer Athey
    JGJesse Grady
    KCKaren Clautice
    MBWMelanie Werdon
    RNRainer Newberry
    WMWalt Munly
    ZDavid Szumigala

    STANO
    Field station identifier (Source: Alaska Division of Geological & Geophysical Surveys)

    Station number unique for a geologist for one calendar year

    SAMPID
    Sample identifier at a field station (Source: Alaska Division of Geological & Geophysical Surveys)

    Sample identifier unique for a field station number

    EASTING
    Easting (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:475775
    Maximum:499955
    Units:meters

    NORTHING
    Northing (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:7096872
    Maximum:7124495
    Units:meters

    BEARING
    Strike of plane, where north is 0 and degrees increase clockwise to 360, always 90 degrees counter-clockwise from dip direction (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

    Range of values
    Minimum:0
    Maximum:360
    Units:degrees

    DIP
    Degrees that a plane is inclined relative to horizonal, horizontal being 0 degrees, vertical being 90 degrees; always 90 degrees clockwise from strike (Source: UTM Zone 7, NAD 27 (see Spatial_Reference_Information))

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

    TYPE
    Type of structure that has the orientation data (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    folfoliation
    vertfolvertical foliation
    flatfolhorizontal foliation
    bedbedding

    SYMBOL
    symbol style coding of structural data (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    1Strike and direction of dip of beds
    9Strike and direction of dip of foliation
    10Strike of vertical foliation
    11Horizontal foliation


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?

    The geologic work was funded by the Alaska State Legislature through a Capital Improvement Project (Alaska Airborne Geophysical/Geological Mineral Inventory Program) and the general fund and through the U.S. Geological Survey STATEMAP program under U.S. Department of the Interior, U.S. Geological Survey, National Cooperative Geologic Mapping Program assistance award 01HQAG0054. 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. DGGS student interns and volunteers providing field assistance include Bryan A. Finseth (1999), Mark Mccrary (1999), J.C.Grady (2000), W.C. Munley (2000), and M.R. Johnson (2001). Milton A. Wiltse provided technical review of the maps. Jessica Mayer provided assistance with surficial geologic studies.

  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
    USA

    (907) 451-5029 (voice)
    (907) 451-5050 (FAX)
    dggspubs@dnr.state.ak.us

    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?

The resulting map and data are intended to provide a geologic map and a geologic interpretation of the Fortymile mining district at 1:63,360 scale. Previously published geologic maps at a 1:63,360 scale of this area have been reconnaissance-level maps or only covered portions of the quadrangle. Mapping at 1:63,360 scale or greater detail 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?

    Foster, 1969 (source 1 of 10)
    Foster, H.L., 1969, Reconnaissance geology of the Eagle A-1 and A-2 quadrangles, Alaska: U.S. Geological Survey Bulletin B 1271-G, United States Government Printing Office, Washington D.C., USA.

    Online Links:

    Other_Citation_Details: p. G1-G30, 1 sheet, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle. See this publication cited in the Process Step section below.

    Flynn and Newberry, 2001 (source 2 of 10)
    Flynn, R.L., and Newberry, R.J., 2001, Geology of the Boundary area, Eagle A-1 Quadrangle, east-central Alaska: U.S. Geological Survey EDMAP program U.S. Geological Survey EDMAP program, under assistance Award No. 00HQAG0061, Flynn, R.L., Fairbanks, AK, USA.

    Other_Citation_Details:
    1 sheet, 1:25,000 scale. Part of Geology M.S. thesis work at University of Alaska, Fairbanks.
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 25000
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle and contribute to the general geologic understanding of the area. See this publication cited in the Process Step section below.

    Day and others, 2002 (source 3 of 10)
    Day, W.C., Aleinikoff, J.N., and Gamble, B.M., 2002, Geochemistry and age constraints on metamorphism and deformation of the Fortymile River area, eastern Yukon-Tanana Upland, Alaska: U.S. Geological Survey Professional Paper P 1662, U.S. Geological Survey, Washington D.C., USA.

    Online Links:

    Other_Citation_Details: p. 4-18
    This is part of the following larger work.

    Wilson, F.H. (ed.), and Galloway, J. (ed.), Unknown, Studies by the U.S. Geological Survey in Alaska, 2000: U.S. Geological Survey Professional Paper P 1662, U.S. Geological Survey, Washington D.C., USA.

    Online Links:

    Other_Citation_Details: 149 pp.
    Type_of_Source_Media: paper
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle and contribute to the general geologic understanding of the area. See this publication cited in the Process Step section below.

    DGGS PDF 1999-9 (source 4 of 10)
    Burns, L.E., Dighem, and Stevens Exploration Management Corp., 1999, CD-ROM containing profile and gridded data and section lines of 1998 geophysical survey data for part of the Fortymile mining district, Alaska, southern Eagle and northern Tanacross quadrangles: Public Data File PDF 99-9, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska, USA.

    Online Links:

    Other_Citation_Details: 2 CD-ROMs
    Type_of_Source_Media: CD-ROM
    Source_Contribution:
    Geologic maps published by DGGS using data from this CD-ROM were referred to frequently during geologic mapping. A list of the geologic maps available is included in a cross-reference publication. See this publication cited in the Process Step section below.

    Yeend, 1996 (source 5 of 10)
    Yeend, W.E., 1996, Gold placers of the historical Fortymile River region, Alaska: U.S. Geological Survey Bulletin B 2125, U.S. Geological Survey, Washington D.C., USA.

    Online Links:

    Other_Citation_Details: 75 pp., 1 sheet, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution: See this publication cited in the Process Step section below

    Werdon and others, 2000 (source 6 of 10)
    Werdon, M.B., Szumigala, D.J., Newberry, R.J., Grady, J.C., and Munly, W.C., 2000, Major oxide, minor oxide, trace element, rare-earth element, and geochemical data from rocks collected in Eagle and Tanacross quadrangles, Alaska in 2000: Raw Data File RDF 2000-4, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 29 p., 3 sheets, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle and contribute to the general geologic understanding of the area. See this publication cited in the Process Step section below.

    Szumigala and others, 2000 (source 7 of 10)
    Szumigala, D.J., Newberry, R.J., Werdon, M.B., Finseth, B.A., Pinney, D.S., and Flynn, R.L., 2000, Major oxide, minor oxide, trace element, and geochemical data from rocks collected in a portion of the Fortymile mining district, Alaska, 1999: Raw Data File RDF 2000-1, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 24 p., 2 sheets, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle and contribute to the general geologic understanding of the area. See this publication cited in the Process Step section below.

    Szumigala and others, 2002 (source 8 of 10)
    Szumigala, D.J., Werdon, M.B., Newberry, R.J., Athey, J.E., Clautice, K.H., Flynn, R.L., Grady, J.C., Munly, W.C., and Johnson, M.R., 2002, Major oxide, minor oxide, trace element, rare-earth element, trace geochemical, and coal quality data from rocks collected in Eagle and Tanacross quadrangles, Alaska in 1999, 2000, and 2001: Raw Data File RDF 2002-1, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 35 p., 1 sheet, scale 1:63,360
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle and contribute to the general geologic understanding of the area. See this publication cited in the Process Step section below.

    Newberry and others, 1998 (source 9 of 10)
    Newberry, R.J., Layer, P.W., Solie, D.N., and Burleigh, R.E., 1998, New 40Ar/39Ar dates for intrusions and mineral prospects in the eastern Yukon-Tanana Terrane, Alaska - regional patterns and significance: U.S. Geological Survey Professional Paper P 1595, U.S. Geological Survey, Washington D.C., USA.

    Online Links:

    Other_Citation_Details: p. 131-159
    This is part of the following larger work.

    Gray, J.E. (ed.), and Riehle, J.R. (ed.), 1998, Geologic studies in Alaska by the USGS, 1996: U.S. Geological Survey Professional Paper P 1595, U.S. Geological Survey, Washington D.C., USA.

    Online Links:

    Other_Citation_Details: 200 p.
    Type_of_Source_Media: paper
    Source_Contribution:
    These data were used to further define the geologic units in the Eagle A-1 Quadrangle and contribute to the general geologic understanding of the area. See this publication cited in the Process Step section below.

    Digital Raster Graphic (DRG), Eagle A-1 (source 10 of 10)
    USGS, 19970808, Digital Raster Graphic (DRG), Eagle A-1: None None, USGS, Reston, VA, USA.

    Online Links:

    Type_of_Source_Media: online
    Source_Contribution:
    This topography was used in the publication as a base for the sample location points. This topography appears as a transparent overlay on the printed geologic maps.

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

    Date: 2001 (process 1 of 7)
    Fieldwork - During the summers of 1999 through 2001 DGGS conducted a geologic field mapping project to provide geologic ground truth for airborne geophysical surveys flown in the Fortymile mining district in 1998. DGGS efforts are focused on determining and understanding the geologic framework of the Fortymile mining district, especially with respect to placer gold and lode mineral deposits. Fieldwork for bedrock investigations, including ridge traverses, roadcut investigations, and river exposures, was conducted for 374 person-days during the months of June through August in 1999 - 2001. Field notes and rock samples were collected at more than 3,880 stations throughout the quadrangle for bedrock investigations. Sixty person-days were spent on field investigations for the surficial geology. Bedrock mapping involved using Burns and others (1999) on a daily basis for checking geologic contacts and units. Bedrock mappers recorded observations on 1:50,000-scale topographic maps of the quadrangle. Stations were located using handheld GPS devices with location precision varying from ±3 to 15 meters. 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, 1999
    • Digital Raster Graphic (DRG), Eagle A-1

    Date: 2001 (process 2 of 7)
    Fieldwork - Fieldwork for surficial investigations, including traverses, roadcut investigations, and river exposures, was conducted for 60 person-days during the months of June through August in 1999 - 2001. 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 co-registered acetate overlays on 1:50,000-scale (nominal) color-infrared aerial photographs, and directly on 1:63,360-scale topographic base maps. Stations were located using air photos and handheld GPS devices with location precision varying from ±3 to 15 meters.

    Data sources used in this process:

    • Yeend, 1996
    • Digital Raster Graphic (DRG), Eagle A-1

    Date: 2002 (process 3 of 7)
    Laboratory data compilation - Laboratory analyses were performed on rock samples collected during the fieldwork process step from July 1999 intermittently through April 2002. Published geochemical and age results are found in Newberry and others (1998), Szumigala and others (2000, 2002), Werdon and others (2000), Flynn and Newberry (2001), Layer and others (in prep.), and Day and others (in press). Unpublished laboratory results include petrographic work on thin sections and modal analysis of rock slabs stained for plagioclase and potassium feldspar. Results from major-oxide and trace-element geochemistry of igneous and metamorphic rocks were used to calculate CIPW Norms for use in classifying rocks according to established petrologic nomenclature. Thin section and some other analytical data were entered into Microsoft Access 2000 databases. Thin sections produced by this study are currently stored at the DGGS office in Fairbanks, Alaska. Rock samples, including geochemical sample pulps and rock hand samples from most field stations, are currently stored at the DGGS office in Fairbanks. Final storage for most rock samples generated by this study will be at the DGGS Geologic Materials Center (GMC) in Eagle River, Alaska.

    Data sources used in this process:

    • Newberry and others, 1998
    • Szumigala and others, 2000
    • Szumigala and others, 2002
    • Werdon and others, 2000
    • Flynn and Newberry, 2001
    • Day and others, in press

    Date: 2002 (process 4 of 7)
    Laboratory data compilation - Laboratory analyses were performed on radiocarbon samples and gold-bearing gravel samples from June 1999 intermittently through April 2002. 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: 2002 (process 5 of 7)
    Geologic map compilation - The bedrock and surficial geologic maps were 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 the quadrangle. The main sources of existing data include Foster (1969), Newberry and others (1988), Yeend (1996), Burns and others (1999), Szumigala and others (2000, 2002), Werdon and others (2000), Flynn and Newberry (2001), Layer and others (in prep.), and Day and others (in press). Bedrock data were compiled on multiple layers of stable mylar at 1:50,000 scale, with some information plotted at 1:25,000 scale for more detail and later transferred to 1:50,000-scale mylar layers. Data were queried from Microsoft Access 2000 databases and plotted on mylar at 1:50,000 scale to answer specific geologic questions. Relevant information from all mylar layers was compiled onto one stable mylar sheet with abundant control points. Surficial-geologic information was interpreted using 1:50,000-scale (nominal) air-photo stereopairs, and compiled onto acetate overlays. The overlay information was transferred to a paper 1:63,360-scale USGS topographic base using a zoom transfer scope.

    Data sources used in this process:

    • Foster, 1969
    • Newberry and others, 1988
    • Yeend, 1996
    • Burns and others, 1999
    • Szumigala and others, 2000
    • Szumigala and others, 2002
    • Werdon and others, 2000
    • Flynn and Newberry, 2001
    • Layer and others, in prep.
    • Day and others, in press
    • Digital Raster Graphic (DRG), Eagle A-1

    Date: 2002 (process 6 of 7)
    Digital cartography - The bedrock-geologic map compilation mylar (above) was scanned by a large-format scanner and saved as a TIFF image. The TIFF image was registered into MapInfo Professional 6.5 with multiple registration points, and a registration error of approximately 2.7 meters (RMS error) was obtained. Geologic contacts and unit polygons were 'on-screen' digitized as complete polygons in MapInfo Professional 6.5. The polygon coverage was translated into Arc/Info format. In Arc/Info 7.0.4, all bedrock unit contacts and polygon coverages were generated from the original file and visual properties were coded. Arc coverages such as fold axes and cross-section traces were also 'on-screen' digitized in MapInfo Professional and translated into Arc/Info file format for visual coding. Station-specific information such as structural measurements, indicator mineral locations, location of age samples, and location of dikes too small to be mappable at 1:63,360 scale were imported into MapInfo Professional 6.5 from a Microsoft Access 2000 database or Excel spreadsheet using GPS locations. MapInfo Professional point coverages were translated into Arc/Info file format and visual properties were coded. Surficial-geologic information was digitized from the paper USGS topographic base map (above) into Arc/Info 7.0.4 GIS (ArcEdit module) using a large-format digitizing table. Surficial-geologic polygons and lines were then edited and attributed using Arc, Info, and ArcEdit. Bedrock point data of locations of structural observations (strike, dip, cleavage, jointing, etc.) and "rubblecrop" were intersected with the surficial-geologic polygon coverage using the Arc command "intersect" in order to identify locations that were mapped as surficial materials based on aerial photography but were found to have small exposures that were desirable to be mapped as bedrock. These areas were then modified in the surficial-geologic coverages to be areas of bedrock exposure. Final bedrock and surficial geology polygon coverages were merged using the Arc command "union" to generate the polygon coverage used to make PIR 2002-1A, the comprehensive geologic map.

    Data sources used in this process:

    • Digital Raster Graphic (DRG), Eagle A-1

    Date: 2002 (process 7 of 7)
    Metadata creation - Metadata were collected by David Szumigala, Jennifer Athey, and De Anne Stevens to FGDC Standards using a text editor and ESRI ArcCatalog 8.1.0.642

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

    Szumigala, D.J., Newberry, R.J., Werdon, M.B., Athey, J.E., Flynn, R.L., and Clautice, K.H., 2002, Bedrock geologic map of the Eagle A-1 Quadrangle, Fortymile mining district: Preliminary Interpretive Report PIR 2002-1B, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

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

    Online Links:

    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?

    Geologic location data were downloaded from Garmin 12XL GPS units into an Access database. Selected sample numbers and locations were queried from the database and brought into a Microsoft Excel 2000 spreadsheet. Spatial reference files were created in MapInfo Professional 6.5 and translated into Arc/Info point coverage format. Data for bedrock-geologic arc and polygon coverages were 'on screen' digitized from a scanned mylar geologic compilation. Bedrock-geologic information was compiled on stable mylar with abundant control points at 1:50,000 scale and registered in MapInfo Professional 6.5, then reduced to a layer onto a 1:63,360-scale USGS topographic base. The surficial-geologic information was transferred from acetate air-photo overlays to a paper 1:63,360-scale USGS topographic base using a zoom transfer scope. The surficial-geologic information was then digitized into Arc/Info GIS (ArcEdit module) using a large-format digitizing table with RMS registration errors constrained to be no larger than 0.003 inches (input coverage units) for each digitizing session. Geologic data included in the compilation are the field maps and notes from this project as well as data from other sources as noted in the "Sources Cited" section.

  2. How accurate are the geographic locations?

    Location data 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 analyzed in MapInfo Professional 6.5. The lists of samples were visually checked against the lists of analyzed samples returned from the laboratories. It was verified that all the samples plotted on the maps are included in the various tables and spreadsheets.

  3. How accurate are the heights or depths?

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

    This dataset includes geospatial information about geologic units, age and field sample locations, structural features, structural measurements, pingo, and dike locations.

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

    Polygon topology present and clean on appropriate data. Other data 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 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, they are 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@dnr.state.ak.us

    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 2002-1A

  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@dnr.state.ak.us

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