Surficial-geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska

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Frequently-anticipated questions:


What does this data set describe?

Title:
Surficial-geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska
Abstract:
This map illustrates the distribution of unconsolidated deposits and undifferentiated bedrcok units in the Salcha River-Pogo area.It was prepared by interpretation of 1:63,360-scale false-color infrared aerial photographs taken July 1978, July 1979, and August 1981, and is locally verified by ground observations during field visits.
Supplemental_Information:
This project includes the following shapefiles:
srp_srfgeo	surficial geology units, polygons
srp_srfcont	surficial geology contacts, lines
srp_pingos	pingos, points
srp_terraces	terrace risers, lines
  1. How should this data set be cited?

    Reger, R.D., Burns, P.A.C., and Staft, L.A., 200812, Surficial-geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska: Report of Investigations RI 2004-1C, Alaska Division of Geological & Geophysical Surveys, Fairbanks, AK.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -145.50000
    East_Bounding_Coordinate: -144.75000
    North_Bounding_Coordinate: 64.75000
    South_Bounding_Coordinate: 64.37500

  3. What does it look like?

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

    Calendar_Date: Jul-1978
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: map

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      This is a Vector data set.

    2. What coordinate system is used to represent geographic features?

      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 0
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      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 0.001
      Ordinates (y-coordinates) are specified to the nearest 0.001
      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 6378137.
      The flattening of the ellipsoid used is 1/298.25722210088.

  7. How does the data set describe geographic features?

    srp_srfgeo.shp
    Surficial geology units, polygons (Source: Alaska Division of Geological & Geophysical Surveys)

    SUNIT
    Surficial-geologic unit shortname (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Qt1Stream-terrace alluvium
    Qt2Stream-terrace alluvium
    QgdUndifferentiated glacial drift
    QaFloodplain alluvium
    QtStream-terrace alluviumAlaska Division of Geological & Geophysical Surveys
    QcUndifferentiated colluvium
    QcdDebris-flow deposit
    QclLandslide deposit
    QcaMixed colluvium and alluvium
    QerRetransported loess
    b'Thinly covered bedrock
    bUndifferentiated bedrock

    DESCRIPTIO
    Text description of surficial unit (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Exposed bedrockExposed bedrock
    Undifferentiated colluviumUndifferentiated colluvium
    Thinly covered bedrockThinly covered bedrock
    Stream-terrace deposits?Possible stream-terrace deposits
    Stream-terrace alluviumStream-terrace alluvium
    Retransported loessRetransported loess
    Mixed colluvium and alluviumMixed colluvium and alluvium
    Landslide depositsLandslide deposits
    Glacial depositsGlacial deposits
    Floodplain alluviumFloodplain alluvium
    Debris-flow depositDebris-flow deposit
    ? Landslide depositPossible landslide deposit
    ? Exposed bedrockPossible exposed bedrock
    Stream-terrace depositsStream-terrace deposits

    Annoname
    Text used to label surficial polygons on map (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    bUndifferentiated bedrock
    b'Thinly covered bedrock
    QcUndifferentiated colluvium
    QcaMixed colluvium and alluvium
    QclLandslide deposit
    QerRetransported loess
    QgdUndifferentiated glacial drift
    QtStream-terrace alluviumAlaska Division of Geological & Geophysical Surveys
    QcdDebris-flow deposit
    QaFloodplain alluvium

    srp_srfcont.shp
    Contacts for surficial-geologic units, polylines (Source: Alaska Division of Geological & Geophysical Surveys)

    srp_pingos.shp
    Locations of pingos, points (Source: Alaska Division of Geological & Geophysical Surveys)

    srp_terraces.shp
    Terrace risers. (Source: ADGGS)

    Entity_and_Attribute_Overview:
    Surficial-geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska Includes the following shapefiles, with associated attributes: srp_srgeo.shp: polygon shapefile, surficial geology polygons - SUNIT(suficial-geologic unit designation), DESCRIPTIO (description of surficial-geologic units), Annoname (the text string that was used to label polygons on the published map) srp_srfcont: polyline shapefile, contacts between surficial-geologic units, used to generate printed map - no manually defined attributes srp_pingos: point shapefile, locations of pingos - no manually defined attributes srp_terraces: line shapefile, terrace risers - no manually definedattributes
    Entity_and_Attribute_Detail_Citation:
    Reger, R.D., Burns, P.A.C.B, and Staft, L.A., 2008, Surficial-geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska: Alaska Division of Geological & Geophysicla Surveys Report of Investigations RI 2004-1C, 1 sheet, scale 1:63,360.


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?

  3. To whom should users address questions about the data?


Why was the data set created?

To show the distribution of unconsolidated deposits and undifferentiated bedrock units in the Salcha River-Pogo area.


How was the data set created?

  1. From what previous works were the data drawn?

    Bacon and others (1996) (source 1 of 4)
    Bacon, C.R., and Lanphere, M.A., 1996, Late Cretaceous age of the Middle Fork Caldera, Eagle Quadrangle, east-central Alaska: U.S. Geological Survey Bulletin B 2152.

    Other_Citation_Details: p. 143-147
    This is part of the following larger work.

    Moore, T.E., and Dumoulin, J.A., 1996, Geologic Studies in Alaska by the U.S. Geological Survey. 1994: U.S. Geological Survey Bulletin B 2152.

    Type_of_Source_Media: paper
    Source_Contribution:
    Information regarding relative stability of Yukon-Tanana Upland.

    Pewe and others (1967) (source 2 of 4)
    Pewe, T.L., Burbank, L., and Mayo, L.R., 1967, Multiple glaciations in the Yukon-Tanana Upland, Alaska: U.S. Geological survey Miscellaneous Investigations Map I 507.

    Other_Citation_Details: 1 sheet, scale 1:500,000
    Type_of_Source_Media: paper
    Source_Contribution:
    Information regarding past glaciation in the Yukon-Tanana Upland.

    Weber (1983) (source 3 of 4)
    Weber, F.R., 1983, Glacial geology of the Yukon-Tanana Upland - a progress report: University of Alaska Museum Occasional Paper No. 2.

    Other_Citation_Details: p. 96-100
    This is part of the following larger work.

    Thorson, R.M., and Hamilton, T.D., 1983, Glaciation in Alaska: Extended abstracts from a workshop: University fo Alaska Museum Occasional Paper No. 2.

    Type_of_Source_Media: paper
    Source_Contribution:
    Information regarding past glaciation in the Yukon-Tanana Upland.

    Weber (1986) (source 4 of 4)
    Weber, F.R., 1986, Glacial geology of the Yukon-Tanana Upland: Alaska Geologicl Society, Anchorage, Alaska.

    Other_Citation_Details: p. 79-98
    This is part of the following larger work.

    Hamilton, T.D., Reed, K.M., and Thorson, R.M., 1986, Glaciation in Alaska: The geologic record: Alaska Geological Society, Anchorage, Alaska.

    Type_of_Source_Media: paper
    Source_Contribution:
    Information regarding past glaciation in the Yukon-Tanana Upland.

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

    Date: 2001 (process 1 of 2)
    Fieldwork- Fieldwork for surficial investigations, including traverses and river exposures, was conducted during the summer of 2001 and 2002.Field notes and sediment samples were collected throughout the map area for surficial investigations. Surficial mapping involved using Pewe and others (1967), and Weber (1983, 1986) on a regular basis for checking glacial geology and general units.Surficial mappers recorded observations on 1:63,360 scale (approximate) color-infrared aerial photographs and 1:63,360 scale topographic base maps. Stations located using air photos and handheld GPS devices with location precision varying from +/-3 to 15 meters.

    Data sources used in this process:

    • Pewe and others (1967)
    • Weber (1983)
    • Weber (1986)

    Date: 2004 (process 2 of 2)
    Geologic map compilation- Surficial geologic map was compiled using field notes from fieldwork process step (above) and all known geologic data from previous work in quadrangle.The main sources of existing data include Bacon and others (1996), Pewe and others (1967), and Weber (1983, 1987). Geologic map contacts were delineated by photointerpretation of 1:63,360-scale color-infrared aerial photographs onto clear acetate overlays. The contacts were transferred from the overlays onto USGS 1:63,360 topographic base maps using a zoom transfer scope, the maps were scanned and georeferenced, and the contacts were then digitized using ArcMap. Polygon topology was established and unit designations assigned in ArcMap. DGGS-standard symbology was applied to polygons, linework, and annotation in ArcMap, and the graphics files were converted into .eps files for export to Adobe Illustrator for final cartographic assembly.

    Data sources used in this process:

    • Bacon and others (1996)
    • Pewe and others (1967)
    • Weber (1983)
    • Weber (1986)

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

    Werdon, M.B., Newberry, R.J., Athey, J.E., and Szumigala, D.J., 2004, Bedrock geologic map of the Salcha River-Pogo area, Big Delta Quadrangle, Alaska: Report of Investigations RI 2004-1B.


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

  1. How well have the observations been checked?

    Initial reconnaissance field observations were made in 2001 and 2002, after which surficial geology air-photo interpretations were done. Contacts were hand-drawn, using a magnifying stereoscope, onto acetate air-photo overlays at the scale of the air-photos (approximately inch-to-the-mile). The air-photos were taken in July 1978, July 1979, and August 1981. During summer field work in 2001 and 2002, map units were described, samples collected for analysis, and a limited number of test pits was dug. The accuracy of the map unit boundary locations vary due to the scale and interpretive nature of the mapping, but are expected to be accurate to at least 20 m. Information from previous geologic reports was incorporated during the interpretation process.

  2. How accurate are the geographic locations?

    The surficial geology was first hand-drawn, using a magnifying stereoscope, onto acetate overlays registered to 1:50,000-scale (nominal) prints of digital aerial photographs. The horizontal accuracy of the map unit boundary locations varies due to the scale and interpretive nature of the mapping, but is expected to be accurate to at least 15 m. Geologic contacts on the acetate overlays were transferred to paper USGS topographic maps using a zoom transfer scope. The paper maps were scanned and georeferenced, and map unit boundaries were digitized on-screen into ArcGIS at a zoomed-in scale of approximately 1:25,000. Total horizontal accuracy of the mapped surficial-geologic contacts is believed to be on the order of 25 m or better, with somewhat lesser accuracy expected in areas of rugged relief.

  3. How accurate are the heights or depths?

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

    This dataset includes shapefiles that contain information about the mapped and interpreted surficial-geologic deposits in the map area. Subsurface data were not available for use in creating these shapefiles, other than scattered soil pits dug to depths no more than about 1 m and observations of exposures in river banks. Soil colors were described using the Munsell soil color charts. The Wentworth scale was used for grain size classification.

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

    Polygon topology is present for polygon shapefiles.


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 data set 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 data sets utilizing these data sets 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 data sets, 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)

    GIS Data Manager
    State of Alaska, DNR, Division of Geological & Geophysical Surveys
    3354 College Road
    Fairbanks, AK 99709-3707

    (907) 451-5029 (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:
    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.
  2. What's the catalog number I need to order this data set?

    Report of Investigations 2004-1C

  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?


Who wrote the metadata?

Dates:
Last modified: 18-Dec-2008
Metadata author:
Metadata Manager
State of Alaska, DNR, Division of Geological & Geophysical Surveys
3354 College Road
Fairbanks, AK 99709-3707

(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 Dec 23 13:25:43 2008