Chert geochemistry discriminant analysis and K-meas cluster analysis: Rampart Project area, Tanana B-1 Quadrangle, east-central Alaska

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What does this data set describe?

Title:
Chert geochemistry discriminant analysis and K-meas cluster analysis: Rampart Project area, Tanana B-1 Quadrangle, east-central Alaska
Abstract:
A pilot study using discriminant analysis on major oxide and minor element data from 67 chert samples in the Rampart area, southeastern Tanana and southwest Livengood Quadrangles, western Yukon-Tanana Upland, Alaska, generally indicates a unique geochemical signature for the cherts of a given unit. Chert samples from five known type locales were used as standards of comparison: 1) Livengood Dome Chert (Ordovician), 2) Amy Creek unit (Proterozoic to early Paleozoic), 3) Rampart Group (Mississippian to Triassic), 4) Troublesome Creek unit (Devonian), and 5) Permian-Triassic clastic unit (associated with the Triassic-dated gabbro). Samples from the above units were compared to chert from Tanana B-1 area-units of unknown or uncertain affinity. We have determined that discriminant analysis of chert geochemistry can assign chert profiles to specific units with only minor exceptions, and is useful in geologic mapping of the Tanana B-1 Quadrangle (Reifenstuhl and others, 1997).
Supplemental_Information:
The data are available in tabular format as comma delimited ascii files organized into one layer in this metadata file under the "Entity_and_Attribute_Information" section. The layer is as follows:
Geochemistry sample locations    sample names and locations, formation designations, geochemical results (Table 1)
  1. How should this data set be cited?

    Reifenstuhl, R.R., Newberry, R.J., Haug, S.A., Clautice, K.H., Liss, S.A., and Weber, F.R., 200903, Chert geochemistry discriminant analysis and K-meas cluster analysis: Rampart Project area, Tanana B-1 Quadrangle, east-central Alaska: Report of Investigation RI 2009-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

    Online Links:

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -150.533
    East_Bounding_Coordinate: -138.333
    North_Bounding_Coordinate: 65.09
    South_Bounding_Coordinate: 65.5333

  3. What does it look like?

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

    Calendar_Date: 1988
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: tabular 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?

      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.00000001. Longitudes are given to the nearest 0.0000001. Latitude and longitude values are specified in Decimal degrees.

      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?

    Table_1_data.csv
    Table 1 is a summary of samples analyzed for geochemistry from the Rampart project area. Information includes sample name, the formation from which the samples were collected, coordinates of sample collection, and the geochemistry results. (Source: Alaska Division of Geological & Geophysical Surveys)

    Sample
    "Sample" refers to the name of the sample given by the geologist. Naming convention is based on the two-digit year, the two-digit collector initials, and a unique sample identifier number. (Source: Alaska Division of Geological & Geophysical Surveys)

    "Sample" refers to a unique identifier assigned by the geologist. Samples are named by 2 digit year, followed by 2-3 digit geologist initials, and a 2-3 digit unique sample number. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, and so forth).

    Rock unit/Comments
    Refers to the geologic uniit from which the sample was collected and/or comments regarding the sample location. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    Amy Creek Dolomite/Livengood Quadranglesample was Amy Creek Dolomite collected in the Livengood 250:000 Quadrangle
    Livengood Dome Chert pit/Livengood Quadranglesample was collected from the Livengood Dome Chert pit in the Livengood 250:000 Quadrangle
    Devonian age-Troublesome Creek Unit/Livengood Quadranglesample is Devonian age, collected from Troublesome Creek Unit in the Livengood 250:000 Quadrangle
    Triassic age chertsample is Triassic age chert
    Livengood Dome Chert?sample may be Livengood Dome Chert
    Amy Creek Dolomite? - location approximatesample may be Amy Creek Dolomite and the collection location is approximated
    Amy Creek Dolomite?sample is questionably Amy Creek Dolomite
    Amy Creek Dolomite?/Tanana A-1 Quadrangle, S19T5N R14Wsample may be Amy Creek Dolomite and the location was not identified by GPS device, but was collected from the Tanana A-1 1:63,360 Quadrangle in specified township and range
    Not Amy Creek DolomiteSample was not Amy Creek Dolomite
    Amy Creek Dolomite? apatite rich!sample is questionably Amy Creek Dolomite, and is apatite-rich
    Not Amy Creek Dolomite or Devonian age unitsample is not Amy Creek Dolomite or Devonian in age
    Livengood Dome Chert? Near sample 96SL174?Sample may be Livengood Dome Chert and was collected near sample 96SL174
    Rampart Groupsample is from the Rampart Group
    Not Livengood Chertsample is not Livengood Dome Chert
    Devonian? or Traissic? SW1/4 S19 T5N R13W, Tanana A-1 Quadranglesample may be Devonian or Triassic and was collected from the specified township and range in the Tanana A-1 1:63,360 Quadrangle
    Amy Creek Dolomite? Livengood Dome Chert?sample may be Amy Creek Dolomite or Livengood Dome Chert

    Latitude (dec. degree)
    Latitude of sample collection measured in decimal degrees (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:65.2542
    Maximum:65.5333
    Units:decimal degrees

    Longitude (dec. degrees)
    Longitude of sample collection measured in decimal degrees (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:-138.333
    Maximum:-150.4151728
    Units:decimal degrees

    Ba
    Elemental Barium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:5
    Maximum:4938
    Units:parts per million (ppm)

    Ce
    Elemental Cesium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:68
    Units:parts per million (ppm)

    Rb
    Elemental Rubidium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:82
    Units:parts per million (ppm)

    Sr
    Elemental Stronium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:1
    Maximum:134
    Units:parts per million (ppm)

    Y
    Elemental Yttrium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:1
    Maximum:90
    Units:parts per million (ppm)

    Zr
    Elemental Zirconium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:1
    Maximum:220
    Units:parts per million (ppm)

    Cr
    Elemental Chromium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:173
    Units:parts per million (ppm)

    V
    Elemental Vanadium (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:3
    Maximum:189
    Units:parts per million (ppm)

    La
    Elemental Lanthanum (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0
    Maximum:40
    Units:parts per million (ppm)

    SiO2
    Silicon Dioxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:99.1
    Maximum:75.6
    Units:weight percent (wt%)

    TiO2
    Titanium Dioxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:.01
    Maximum:.66
    Units:weight percent (wt%)

    Al3O3
    Aluminum Oxide (Source: Alaska Division of Geologica & Geophysical Surveys)

    Range of values
    Minimum:.2
    Maximum:10.89
    Units:weight percent (wt%)

    Fe2O3
    Iron Oxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:.03
    Maximum:8.49
    Units:weight percent (wt%)

    MnO
    Manganese Oxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0.00
    Maximum:.40
    Units:weight percent (wt%)

    MgO
    Magnesium Oxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:.03
    Maximum:3.79
    Units:weight percent (wt%)

    CaO
    Calcium Oxide (Source: Alaska Divsion of Geological & Geophysical Surveys)

    Range of values
    Minimum:0.0
    Maximum:7.83
    Units:weight percent (wt%)

    Na2O
    Sodium Oxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0.0
    Maximum:2.76
    Units:weight percent (wt%)

    K2O
    Potassium Oxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0.0
    Maximum:2.25
    Units:weight percent (wt%)

    P2O5
    Phosphorous Oxide (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:0.0
    Maximum:6.4
    Units:weight percent (wt%)


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?

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

    (907) 451-5020 (voice)
    (907) 451-5050 (FAX)
    dggspubs@alaska.gov

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


Why was the data set created?

This data was created to determine if discriminant analysis of chert geochemistry can assign chert profiles to specific units in order to facilitate geologic mapping of the Tanana B-1 Quadrangle


How was the data set created?

  1. From what previous works were the data drawn?

    Dover, 1994 (source 1 of 2)
    Dover, J.H., 1994, Geology of part of east-central Alaska: Geological Society of America, Boulder, CO.

    Other_Citation_Details: in Plafker, G., and Berg, H.C., eds,. The Geology of Alaska
    Type_of_Source_Media: paper
    Source_Contribution: source of regional geologic rock unit distribution

    Weber and others, 1992 (source 2 of 2)
    Weber, F.R., Wheeler, K.L., Rinchart, C.D., Chapman, R.M., and Blodgett, R.B., 1992, Geologic map of the Livengood quadrangle, Alaska: U.S. Geological Survey Open-File Report 92-562.

    Other_Citation_Details: 20 p., 1 sheet (scale 1:250,000)
    Type_of_Source_Media: paper
    Source_Contribution:
    Source of regional geologic rock unit distribution, description and correlation of surface exposures immediately east of the Tanana B-1 map area.

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

    Date: 1996 (process 1 of 2)
    As part of our 1:63,360 scale geologic field mapping of the Tanana B-1 Quadrangle, we collected chert outcrop samples with the plan of using geochemistry to test whether we might be able to discern differences in the cherts of different ages and different mappable rock units.

    Data sources used in this process:

    • Dover, 1994
    • Weber and others, 1992

    Date: 1998 (process 2 of 2)
    The collected cherts were crushed and pelletized for X-Ray Fluorescence analyses at the University of Alaska Fairbanks. The pellets were analyzed for nineteen elements: ten major oxide elements measured in weight percent (aluminum, calcium, iron, potassium, magnesium, manganese, sodium, phosphorous, silicon, and titanium) and nine trace elements measured in parts per million (barium, cerium, chromium, lanthanum, rubidium, strontium, vanadium, yttrium, and zirconium).

  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?

    Attributes in this dataset consist of: positional information reported in latitude and longitude (decimal degrees - NAD27) and major oxide and minor element geochemical data. All field locations were visually determined by the geologists in the field using a Brunton compass and altimeter and recorded on a 1:63,360 United States Geologic Survey topographic map. Coordinates were digitized visually from the field maps in the office on a digitizing table. The collected cherts were crushed and pelletized for X-Ray Fluorescence analyses at the University of Alaska Fairbanks, further detail regarding analytical methodology is not available.

  2. How accurate are the geographic locations?

    Exact horizontal position accuracy is unknown but the locations are estimated to be accurate within 20 meters. Several samples have unknown or vaugely known localities and are noted as '---' within the dataset.

  3. How accurate are the heights or depths?

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

    This dataset contains all of the chert samples that were collected from outcrops in the Tanana A-1 quadrangles from rock units of unknown or uncertain affinity. Representative samples of cherts typical each of local were selected based on a visual determination of their lithology. In addition several samples that were collected outside the primary area were also included.

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

    No topologic relationships are present in this data set.


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
Use_Constraints:
Any hardcopies 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.


Who wrote the metadata?

Dates:
Last modified: 26-Feb-2009
Metadata author:
Alaska Division of Geological & Geophysical Surveys
3354 College Road
Fairbanks, Alaska 99709
United States

(907) 451-5010 (voice)
dggspubs@alaska.gov

Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)


Generated by mp version 2.9.6 on Mon Mar 16 11:19:59 2009