Geologic map of the Upper Chena River area, eastern interior Alaska

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Frequently-anticipated questions:


What does this data set describe?

Title:
Geologic map of the Upper Chena River area, eastern interior Alaska
Abstract:
Geologic studies of the upper Chena River area were undertaken in 1983 as part of the Interior Mining District Evaluation Program, a series of projects designed to develop new information on known mineral districts in interior Alaska. During the three-year course of the program, geologists examined four districts that have contributed significantly to historical gold production in Alaska's Interior, Fairbanks, Livengood, Richardson, and upper Chena River.
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 "PR115_codeset.pdf." Layers include:
uchenaage_label     whole rock major oxide or age date sample (points)
uchenaatt_point     strike, dip, and fold axis attitude
uchenageo_arc     geologic units (arc)
uchenageo_polygon     geologic units (polygons)
uchenalin_arc     concealed bedrock contacts
uchenastr_arc     fold and fault traces (arc)
uchenastr_point     fold and fault traces (points)
uchengrit_polygon     areas of rubble
uchenstr2_arc     shear zones
  1. How should this data set be cited?

    Smith, T.E., Robinson, M.S., Weber, F.R., Waythomas, C.F., and Reifenstuhl, R.R., 1994, Geologic map of the Upper Chena River area, eastern interior Alaska: Professional Report PR 115, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska - USA.

    Online Links:

    Other_Citation_Details: 19 p., 1 sheet, scale 1:63,360

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -145.516417
    East_Bounding_Coordinate: -144.484263
    North_Bounding_Coordinate: 65.147819
    South_Bounding_Coordinate: 64.805281

  3. What does it look like?

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

    Calendar_Date: 1994
    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: 6
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -147.00000
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.0
      False_Northing: 0

      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest 0.000128
      Ordinates (y-coordinates) are specified to the nearest 0.000128
      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?

    uchenageo_polygon.shp
    Object type is vector, there are 1753 rows associated with this entity, and the entity values refer to the unit name abbreviations for each specific polygon represented on the map. (Source: Alaska Division of Geological & Geophysical Surveys)

    UNIT
    A unique three to four letter abbreviation given to each map unit represented on the map. (Source: Alaska Division of Geological & Geophysical Surveys)

    Formal codeset
    Codeset Name:PR115_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys <http://www.dggs.alaska.gov/metadata/PR115_codeset.pdf>

    uchenageo_arc.shp
    Object type is vector, there are 4785 rows associated with this entity, and the entity values refer to geologic map unit contacts. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol representing type of contact between geologic units. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    0Boundary to unmapped area.
    15Thrust fault - saw teeth on upper plate; approximately located.
    16Thrust fault - saw teeth on upper plate; questionable.
    25Contact.

    uchenaatt_point.shp
    Object type is point, there are 776 rows associated with this entity, and the entity values refer to the strike, dip, and fold axis attitude. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol representing types of attitudes. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    3Strike and dip of vertical beds.
    5Strike and dip of foliation; inclined.
    9Crumpled, undulatory beds.
    12Strike and dip of foliation, vertical.
    14Strike and dip of foliation, horizontal.
    15Strike and dip of joints, inclined.
    24Strike and dip of joints, vertical.
    33Bearing and plunge of lineation; c, crenulation; f, minor fold axis; q, quartz boudins; m, mineral.
    44Strike and dip of cleavage.

    uchenastr_arc.shp
    Object type is vector, there are 152 rows associated with this entity, and the entity values refer to all fold axes and fault traces. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol representing type of fold axis and fault trace. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    2High-angle fault, approximately located. Arrows show apparent direction of relative horizontal movement. U, upthrown block; D, downside block.
    3High-angle fault, concealed. Arrows show apparent direction of relative horizontal movement. U, upthrown block; D, downside block.
    5High-angle fault, concealed. Arrows show apparent direction of relative horizontal movement. U, upthrown block; D, downside block.
    6High-angle fault, queried where questionable.
    13Thrust fault - saw teeth on upper plate. Enclosed circle.
    14Thrust fault - saw teeth on upper plate.
    15Thrust fault - saw teeth on upper plate. Dashed where approximately located.
    16Thrust fault - saw teeth on upper plate. Dashed where approximately located. Queried where questionable.
    17Thrust fault - saw teeth on upper plate. Dotted where concealed.
    18Thrust fault - saw teeth on upper plate. Dotted where concealed. Queried where questionable.
    31Trace and plunge of fold axis.
    37High-angle fault. U, upthrown block; D, downside block.

    uchenastr_point.shp
    Object type is point, there are 8 rows associated with this entity, and the entity values refer to all fold axes and fault traces. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbols that represent the types of structural features. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    16Trace and plunge of anticlinal fold axis.
    17Trace and plunge of synclinal fold axis.
    144High angle fault - arrows show apparent direction of relative horizontal movement.

    uchenalin_arc.shp
    Object type is vector, there are 198 rows associated with this entity, and the entity values refer to concealed bedrock contacts. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol representing concealed bedrock contacts. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    27Concealed bedrock contacts as interpreted by T.E. Smith.

    uchenstr2_arc.shp
    Object type is vector, there are 6 rows associated with this entity, and the entity values refer to areas of shear zones. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Symbol representing areas of shear zones. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    1Shear Zone - undetermined offset.

    uchengrit_polygon.shp
    Object type is vector, there are 6 rows associated with this entity, and the entity values refer to areas of rubble. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Area of rubble. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    4Area of bi-modal "quartz-eye" quartzite rubble, mainly in Pcu unit.
    50Area of augen gneiss (Pzra) rubble.

    uchenaage_label.shp
    Object type is point, there are 27 rows associated with this entity, and the entity values refer to sample locations for whole rock major oxide and age dating analysis. (Source: Alaska Division of Geological & Geophysical Surveys)

    SYMBOL
    Sample locations for whole rock major oxide and age dating. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    128Location of sample for whole rock major oxide or age dating.


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 Alaska legislature provided funding for the studies through capital and operating budget appropriations. Additional Acknowledgments: Geology by T.E. Smith, M.S. Robinson, F.R. Weber, C.F. Waythomas, and R.R. Reifenstuhl, assisted by D.D. Adams, G.L. Allegro, T.D. Balog, D.A. Coleman, J.W. Lindhorst, J.M. Murphy, and D.D. Southworth. Geochronology by J.N. Aleinikoff, U.S. Geological Survey, J.K. Mortenson, Geological Survey of Canada, D.L. Turner, University of Alaska Fairbanks, and F.H. Wilson, U.S. Geological Survey. Richard D. Reger and Richard C. Swainbank provided technical review and Fran Tannian provided a thorough edit. Digital cartography by Fred Sturmann.

  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.alaska.gov> 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 authors chose to study the upper Chena River district to better understand (1) the source of placer gold resources near Van Curler's Bar, (2) the nature and production potential of tungsten-bearing skarns in the eastern map area, and (3) a proposed route of a transportation corridor through the area. The greatest contribution of this map and report was drawing the striking parallism between Upper Chena stratigraphy with its associated metallogeny and that of the north flank of the Alaska Range.


How was the data set created?

  1. From what previous works were the data drawn?

    Wahrhaftig, 1968 (source 1 of 2)
    Wahrhaftig, Clyde, 1968, Schists of the central Alaska Range: U.S. Geological Survey Bulletin B 1254-E, U.S. Geological Survey, Denver, CO.

    Online Links:

    Other_Citation_Details: p. E1-E22
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 50000
    Source_Contribution:
    This publication helped with detailed description and samples from the Alaska Range stratigraphy.

    Bundtzen and others, 1976 (source 2 of 2)
    Bundtzen, T.K., Smith, T.E., and Tosdal, R.M., 1976, Progress report: Geology and mineral deposits of the Kantishna Hills, Alaska: Alaska Open-File Report AOF 98, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

    Online Links:

    Other_Citation_Details: 82 p., 2 sheets, scale 1:63,360
    This is part of the following larger work.

    (ed.), George Plafker , and (ed)., H.C. Berg , 1994, The Geology of Alaska: The Geology of North America v. G1, Geological Society of America, Boulder, Colorado.

    Type_of_Source_Media: paper
    Source_Scale_Denominator: 63360
    Source_Contribution:
    This publication helped with detailed description and samples from the Alaska Range stratigraphy.

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

    Date: Unknown (process 1 of 2)
    Fieldwork - Mappers recorded observations in field notebooks and on the aerial photographs and topographic maps, predominantly at 1:63,360 scale. In some areas, photocopies of topography at varying enlarged scales were used. All compilations were made by hand on stable Mylar at 1:63,360 scale. Locations were determined visually in the field by reference to surrounding topography and sometimes by triangulation with Brunton compasses.

    Date: Unknown (process 2 of 2)
    Geologic map compilation - Data for geologic coverages was digitized off of a Mylar geologic compilation. This compilation was done on a one to one scale, stable Mylar of the USGS topographic base for each of the 1:63,360 scale USGS topographic bases included in the map area. The bedrock geologic map was compiled using field notes from fieldwork process step (above). Wahrhaftig 1968 and Bundtzen and others, 1976 helped with detailed description and samples from the Alaska Range stratigraphy.

    Data sources used in this process:

    • Wahrhaftig, 1968
    • Bundtzen and others, 1976

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


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

  1. How well have the observations been checked?

    Geologic point, line, and polygon data were determined in the field using 1:63,360-scale topographic maps and 1:50,000 (nominal) scale, color-infrared aerial photographs. 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 determined visually using topographic maps at a scale of 1:63,360 and 1:50,000 (nominal) scale, and black and white aerial photographs.

  3. How accurate are the heights or depths?

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

    This dataset includes geospatial information related to geologic units, fold and fault traces, strike, dip, and fold axis attitude, concealed bedrock contacts, shear zones, areas of rubble and whole rock major oxide or age date samples.

  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/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.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?

    Professional Report 115

  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 14:29:37 2008