Surficial-geologic map of the Chulitna region, southcentral Alaska

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Frequently-anticipated questions:


What does this data set describe?

Title:
Surficial-geologic map of the Chulitna region, southcentral Alaska
Abstract:
This map is the result of field investigations by DGGS in 1997 and 1998. This geologic map and report supersede the previously released Public Data File 99-24C, Preliminary surficial-geologic map of the Healy A-6 Quadrangle, southcentral Alaska. The current map has been updated to include mapping of areas adjacent to the Healy A-6 Quadrangle. Field investigations were part of a two-year mapping program to provide geologic ground truth for airborne geophysical surveys flown by DGGS in the Chulitna region of southcentral Alaska during 1996.
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 "RI2001-1_codeset.pdf." Layers include:
chu_allsrfgeo_arc     surficial geologic unit boundaries (arc)
chu_allsrfgeo_polygon     surficial geologic units (polygon)
chu_eskers_arc     vector lines for eskers
chu_terrace_arc     vector lines for terraces
  1. How should this data set be cited?

    Pinney, D.S., 2001, Surficial-geologic map of the Chulitna region, southcentral Alaska: Report of Investigation RI 2001-1C, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska - USA.

    Online Links:

    Other_Citation_Details: 3 p., 1 sheet, scale 1:63,360

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -150.030246
    East_Bounding_Coordinate: -149.090702
    North_Bounding_Coordinate: 63.307690
    South_Bounding_Coordinate: 62.958985

  3. What does it look like?

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

    Beginning_Date: 1997
    Ending_Date: 2001
    Currentness_Reference: publication date

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

    Geospatial_Data_Presentation_Form: report, 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: 0.9996
      Longitude_of_Central_Meridian: -147.000
      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 0.000128
      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?

    chu_terraces_arc.shp
    Object type is vector, there are 153 rows associated with this entity, and the entity values refer to stream terrace risers (Source: Alaska Division of Geological & Geophysical Surveys)

    symbol
    Line symbol for surficial features (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    58Stream terrace riser, with hatchures pointing downslope

    chu_eskers_arc.shp
    Object type is vector, there are 29 rows associated with this entity, there are no attributes associated with this entity, and the entity values refer to esker crests (Source: Alaska Division of Geological & Geophysical Surveys)

    chu_allsrfgeo_arc.shp
    Object type is vector, there are 3849 rows associated with this entity, and the entity values refer to surficial geologic map unit contacts. (Source: Alaska Division of Geological & Geophysical Surveys)

    CODE
    Line symbol for surficial geologic map unit contacts (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    6Contact, approximately located

    chu_allsrfgeo_polygon.shp
    Object type is vector, there are 1604 rows associated with this entity, and the entity values refer to surficial geologic map units. (Source: Alaska Division of Geological & Geophysical Surveys)

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

    ValueDefinition
    bUndifferentiated bedrock
    bcThinly covered bedrock
    lakeLake
    glacierGlacier

    Formal codeset
    Codeset Name:RI2001-1_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys <http://www.dggs.dnr.state.ak.us/metadata/RI2001-1_codeset.pdf>

    X-COORD
    X-coordinate (Source: ESRI, Arc command "addxy", numeric coordinates defining feature location)

    Range of values
    Minimum:0
    Maximum:393398.2
    Units:meters

    Y-COORD
    Y-coordinate (Source: ESRI, Arc command "addxy", numeric coordinates defining feature location)

    Range of values
    Minimum:0
    Maximum:7021089
    Units:meters

    SUNIT
    Surficial map unit labels, indicates source of the unit name is from the Surficial-geologic map of the Chulitna region, southcentral Alaska (RI 2001-1C). Any unit ending with a "?" indicates uncertainty (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    bUndifferentiated bedrock
    bcThinly covered bedrock
    lakeLake
    glacierGlacier

    Formal codeset
    Codeset Name:RI2001-1_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys <http://www.dggs.dnr.state.ak.us/metadata/RI2001-1_codeset.pdf>

    SURFBED
    Code designator to distinguish areas of surficial deposits from areas of bedrock deposits (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    SSurficial deposit
    BBedrock deposit, including exposed and thinly-covered units

    JUSTBED
    Map unit labels in which all exposed bedrock and thinly covered bedrock are combined into a single bedrock unit, whereas the surficial-geologic deposits retain their original unit designations. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    BXUndifferentiated bedrock and thinly covered bedrock
    lakeLake
    glacierGlacier

    Formal codeset
    Codeset Name:RI2001-1_codeset.pdf
    Codeset Source:Alaska Division of Geological & Geophysical Surveys <http://www.dggs.dnr.state.ak.us/metadata/RI2001-1_codeset.pdf>


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 Chulitna project is part of DGGS's Airborne Geophysical and Geological Mineral Inventory project (AGGMI), a special multi-year investment by the State of Alaska to produce framework geologic maps that will expand the knowledge base of Alaska's geologic and mineral resources, catalyze future private-sector mineral exploration and development, and guide government agencies' planning projects. The AGGMI project is 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 Chulitna project was also provided by the U.S. Geological Survey under U.S. Department of the Interior, U.S. Geological Survey, National Cooperative Geological Survey STATEMAP Cooperative Agreement 98HQAG2083. 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?

The purpose of this project was to produce a 1:63,360-scale geologic map for the airborne geophysical surveys released by DGGS in the Chulitna region during 1996. The geologic data are important for identifying potential mineral deposits and for characterizing and distinguishing between geologic units.


How was the data set created?

  1. From what previous works were the data drawn?

    Reger and Pinney, 1996 (source 1 of 3)
    Reger, R.D., and Pinney, D.S., 1996, Late Wisconsin glaciation of the Cook Inlet region with emphasis on Kenai Lowland and implications for early peopling: None None, Cook Inlet Historical Society, Anchorage, Alaska.

    Online Links:

    • None

    Other_Citation_Details: p. 15-35
    This is part of the following larger work.

    Davis, N.Y. (ed.), and Davis, W.E. (ed.), 1996, Readings in the anthropology of Cook Inlet, Alaska: None None, Cook Inlet Historical Society, Anchorage, Alaska.

    Other_Citation_Details: p. 15-35
    Type_of_Source_Media: Paper report
    Source_Contribution:
    These data were used to further define the geology of the Chulitna area. See this publication cited in the Process Step section below.

    Ten Brink, 1983 (source 2 of 3)
    Ten Brink, N.W., 1983, Glaciation of the northern Alaska Range: University of Alaska Museum Occasional Paper No. 2, Alaska Quaternary Center, Fairbanks, Alaska.

    Online Links:

    • None

    Other_Citation_Details: Pages 82-91 of larger work
    This is part of the following larger work.

    Thorson, R.M (ed.), and Hamilton, T.D. (ed.), 1983, Glaciation in Alaska: Extended abstracts from a workshop: University of Alaska Museum Occasional Paper No. 2, Alaska Quaternary Center, Fairbanks, Alaska.

    Other_Citation_Details: Used pages 82-91 from this publication
    Type_of_Source_Media: paper
    Source_Contribution:
    These data were used to further define the geology of the Chulitna area. See this publication cited in the Process Step section below.

    Wahrhaftig, 1958 (source 3 of 3)
    Wahrhaftig, Clyde, 1958, Quaternary geology of the Nenana River valley and adjacent parts of the Alaska Range: U.S. Geological Survey Professional Paper PP 293-A, United States Government Printing Office, Washington, D.C..

    Online Links:

    • None

    Other_Citation_Details: p. 1-68
    This is part of the following larger work.

    Wahrhaftig, Clyde, and Black, R.F., 1958, Quaternary and engineering geology in the central part of the Alaska Range: U.S. Geological Survey Professional Paper PP 293, United States Government Printing Office, Washington, D.C..

    Other_Citation_Details: p. 1-68
    Type_of_Source_Media: paper
    Source_Scale_Denominator: 250000
    Source_Contribution:
    These data were used to further define the geology of the Chulitna area. See this publication cited in the Process Step section below.

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

    Date: 1998 (process 1 of 3)
    Fieldwork - Fieldwork for geologic investigations, including ridge and valley traverses, road cut investigations, and river exposures, was conducted for approximately seven person-days in June 1997 by a surficial geologist. Field notes and sediment samples were collected throughout the area for surficial investigations. Surficial mapping involved using Reger and Pinney (1996), Ten Brink (1983), and Wahrhaftig (1958) on a regular basis for checking and correlating general units. Surficial mapper 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 topographic maps.

    Data sources used in this process:

    • Reger and Pinney, 1996
    • Ten Brink, 1983
    • Wahrhaftig, 1958

    Date: 1998 (process 2 of 3)
    Photo interpretation - Before, during, and after fieldwork, surficial-geologic information was interpreted using 1:50,000-scale (nominal) color-infrared air-photo stereopairs, and compiled onto acetate overlays. Photo interpretation was based on field notes from fieldwork process step (above), observed land forms and relationships in the photos, and all known geologic data from previous work in the area. The main sources of existing data include Reger and Pinney (1996), Ten Brink (1983), and Wahrhaftig (1958). The overlay information was transferred to a paper 1:63,360-scale USGS topographic base using a zoom transfer scope.

    Date: 2001 (process 3 of 3)
    Digital cartography - 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.) 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 RI 2001-1B, the comprehensive geologic map.

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

    Gage, B.G., Liss, S.A., and Clautice, K.H., 199810, Preliminary geochemical and major oxide data: Chulitna project, Healy A-6 Quadrangle and nearby areas (1997 and 1998): Public Data File PDF 1998-36, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

    Online Links:

    Other_Citation_Details: 48 p., 2 sheets, scale 1:63,360, 1 disk
    Blodgett, R.B., and Clautice, K.H., 2000, Fossil locality map for the Healy A-6 Quadrangle, southcentral Alaska: Report of Investigation RI 2000-5, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

    Online Links:

    Other_Citation_Details: 42 p., 1 sheet, scale 1:63,360
    Clautice, K.H., Newberry, R.J., Blodgett, R.B., Bundtzen, T.K., Gage, B.G., Harris, E.E., Liss, S.A., Miller, M.L., Reifenstuhl, R.R., Clough, J.G., and Pinney, D.S., 2001, Bedrock geologic map of the Chulitna region, southcentral Alaska: Report of Investigation RI 2001-1A, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, Alaska - USA.

    Online Links:

    Other_Citation_Details: 31 p., 1 sheet, scale 1:63,360
    Clautice, K.H., Newberry, R.J., Pinney, D.S., Blodgett, R.B., Bundtzen, T.K., Gage, B.G., Harris, E.E., Liss, S.A., Miller, M.L., Reifenstuhl, R.R., and Clough, J.G., 2001, Geologic map of the Chulitna region, southcentral Alaska: Report of Investigation RI 2001-1B, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 32 p., 1 sheet, scale 1:63,360
    Pinney, D.S., 2001, Engineering-geologic map of the Chulitna region, southcentral Alaska: Report of Investigation RI 2001-1D, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

    Other_Citation_Details: 5 p., 1 sheet, scale 1:63,360
    Burns, L.E., Dighem, and WGM Mining and Geological Consultants, 1997, CD-ROM digital archive files of 1996 survey data for Chulitna and Petersville mining districts, Alaska: Public Data File PDF 97-5, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 1 CD-ROM
    Pritchard, R.A., and Dighem, 1997, Project report of the airborne geophysical survey for the Chulitna and Petersville mining districts, Alaska: Public Data File PDF 97-8, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 293 p., 2 sheets, scale 1:63,360
    Burns, L.E., 1997, Portfolio of aeromagnetic and resistivity maps of the Chulitna mining district: Public Data File PDF 97-7, State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys, Fairbanks, AK, USA.

    Online Links:

    Other_Citation_Details: 13 p., 1 sheet


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. 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 determined visually using topographic maps at a scale of 1:63,360 and 1:50,000 (nominal) scale, color-infrared 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 about geologic units and land forms.

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

    Polygon topology present and clean on appropriate data; others are line or point data.


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?

    Report of Investigation 2001-1C

  3. What legal disclaimers am I supposed to read?

    The State of Alaska makes no express or implied warranties (including warranties of merchantability and fitness) with respect to the character, function, or capabilities of the electronic services or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products, any failure thereof, or otherwise, and in no event will the State of Alaska's liability to the requester or anyone else exceed the fee paid for the electronic service or product.

  4. How can I download or order the data?

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

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


Who wrote the metadata?

Dates:
Last modified: 06-May-2008
Last Reviewed: 06-May-2008
To be reviewed: 15-Mar-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 14:29:39 2008