40Ar/39Ar data from rocks collected in 2013 in the Wrangellia mineral assessment area, Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles, Alaska

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Frequently anticipated questions:

What does this data set describe?

Title:
40Ar/39Ar data from rocks collected in 2013 in the Wrangellia mineral assessment area, Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles, Alaska
Abstract:
This DGGS report presents 40Ar/39Ar age dating results from selected mafic to intermediate intrusions encountered during a geological and geochemical resource assessment project in the Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles. Three intrusions returned mid-Cretaceous crystallization ages, while one olivine gabbro returned a Late Triassic crystallization age. Two altered or metamorphosed samples yielded Late Jurassic and Early Cretaceous ages. Analyses were performed by the University of Alaska Fairbanks Geochronology Laboratory, and results were reported by Paul Layer and Jeff Benowitz. Products included in this data release are: a summary of sample collection method; the laboratory report, analytical data tables and associated metadata; and plots of the 40Ar/39Ar age spectra, Ca/K ratios, and Cl/K ratios. All components of this data release are available on the DGGS website doi:10.14509/29119 at no charge.
Supplemental_Information:
The DGGS metadata standard extends the FGDC standard to include elements that are required to facilitate our internal data management. These elements, referred to as "layers," group and describe files that have intrinsic logical or topological relationships and correspond to subdirectories within the data distribution package. The metadata layer provides an FGDC metadata file and may include other documentation files. Attribute information for each data layer is described in this metadata file under the "Entity_and_Attribute_Information" section. Data layer contents: 
border:    Outline of the study area
arar-summary-data-locations:    Identification numbers, coordinates, sample descriptions, and summary ages of each sample
step-heating-data:    Power output levels and resultant measurements from each sample run
  1. How should this data set be cited?

    Benowitz, J.A., Layer, P.W., and Twelker, Evan, 2014, 40Ar/39Ar data from rocks collected in 2013 in the Wrangellia mineral assessment area, Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles, Alaska: Raw Data File RDF 2014-18, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -148.807913
    East_Bounding_Coordinate: -145.948239
    North_Bounding_Coordinate: 63.221415
    South_Bounding_Coordinate: 62.568967

  3. What does it look like?

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

    Calendar_Date: 2014
    Currentness_Reference: ground condition

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

    Geospatial_Data_Presentation_Form: report,digital data

  6. How does the data set represent geographic features?

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

      This is a point 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 0.00001. Longitudes are given to the nearest 0.00001. Latitude and longitude values are specified in decimal degrees.

      The horizontal datum used is World Geodetic System of 1984.
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257223563.

  7. How does the data set describe geographic features?

    rdf2014-18-border.shp
    Outline of the study area (Source: Alaska Division of Geological & Geophysical Surveys)

    rdf2014-18-arar-summary-data-locations.csv
    Identification numbers, coordinates, sample descriptions, and summary ages of each sample (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPLE
    Label assigned in the field to identify the sample. (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a sample identifier: YYAAA9999X: YY=last two digits of year, AAA=geologist's initials (one to three characters), 9999=unique station number, X= optional alpha character which indicates that multiple samples were collected at a given location or that multiple observations were recorded in the project database.

    LAB_SAMPLE_NUMBER
    Label used by the lab to identify the sample. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The lab sample number is typically identical to the field sample number. However, in some cases, the sample number provided by the lab does differ from the number assigned in the field. We provide both numbers to document instances in which the sample numbers in the lab files differ from the field sample number.

    LONGITUDE
    Longitude, NAD27 (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:-148.807913
    Maximum:-145.948239

    LATITUDE
    Latitude, NAD27 (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:62.568967
    Maximum:63.221415

    DESCRIPTION
    Description of the sample (Source: Alaska Division of Geological & Geophysical Surveys)

    Characters 1 to 254 of a brief sample or station description.

    DESCRIP_2
    Extension of the sample or station description for descriptions which are greater than 254 characters in length (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLBlank (NULL) values indicate that the descriptive text is shorter than 254 characters.

    Characters greater than 254 of the sample or station description.

    DATED_MATERIAL
    Indicates the type of material that was used for analysis (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The type of material that was selected for dating varied according to mineral composition and grainsize of the submitted rock sample. This field specifies whether the age was derived from a mineral separate (generally 1 to 10 individual crystals dated together as a single run), a single crystal, or the whole rock.

    MINERAL
    Indicates the mineral that was used for analysis (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The minerals selected for dating would typically be grains of biotite, hornblende, or muscovite.

    INTEGRATED_AGE_MA
    Integrated age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The values are a concatenation of the integrated age determination and the calculated error associated with the integrated age determination

    PLATEAU_AGE_MA
    Plateau age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the PLATEAU_AGE_MA value was not calculated by the lab

    The values are a concatenation of the plateau age determination and the calculated error associated with the plateau age determination

    PLATEAU_PERCENT_39AR
    Value in percent of the 39 Ar used in that portion of the spectrum to determine the plateau age (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:46.9
    Maximum:94.6
    Units:percent

    PLATEAU_MSWD
    The mean square weighted deviation of the plateau age calculation (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the value was not calculated by the lab

    Range of values
    Minimum:0.75
    Maximum:2.46

    PLATEAU_REMARKS
    Comments and additional values that pertain to the plateau age determination method or interpretation. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the PLATEAU_REMARKS value was not provided by the lab

    Free text

    AVG_AGE_MA
    Weighted average age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the AVG_AGE_MA value was not calculated by the lab

    The values are a concatenation of the weighted average age determination and the calculated error associated with the weighted average age determination

    AVG_AGE_MSWD
    The mean square weighted deviation of the weighted average age calculation (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the value was not calculated by the lab

    Range of values
    Minimum:3.81
    Maximum:4.29

    AVG_AGE_REMARKS
    Comments and additional values that pertain to the weighted average age determination method or interpretation. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the AVG_AGE_REMARKS value was not provided by the lab

    Free text

    ISOCHRON_AGE
    Isochon age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the ISOCHRON_AGE value was not provided by the lab

    The values are a concatenation of the isochron age determination and the calculated error associated with the isochron age determination

    ISOCHRON_MSWD
    The mean square weighted deviation of the isochron age calculation (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the value was not calculated by the lab

    ISOCHRON_REMARKS
    Comments and additional values that pertain to the isochon age determination method or interpretation. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the ISOCHRON_REMARKS value was not provided by the lab

    Free text

    AGE_TYPE_PREFERRED
    Indicates AGE_TYPE_PREFERRED age. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    A discussion of the preferred age for each analysis is provided in the accompanying lab report. The possible values are: plateau, isochron, weighted average, or integrated.

    PREFERRED_AGE
    The values are a concatenation of the preferred age determination and the calculated error associated with the preferred age determination (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The preferred age for each analysis is discussed in detail in the accompanying lab report.

    rdf2014-18-arar-summary-data-locations.csv
    Identification numbers, coordinates, sample descriptions, and summary ages of each sample (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPLE
    Label assigned in the field to identify the sample. (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a sample identifier: YYAAA9999X: YY=last two digits of year, AAA=geologist's initials (one to three characters), 9999=unique station number, X= optional alpha character which indicates that multiple samples were collected at a given location or that multiple observations were recorded in the project database. The initials used by the geologists who collected samples for this project are: ET = Evan Twelker, LF = Larry K. Freeman and RN = Rainer J. Newberry

    LAB_SAMPLE_NUMBER
    Label used by the lab to identify the sample. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The lab sample number is typically identical to the field sample number. However, in some cases, the sample number provided by the lab does differ from the number assigned in the field. We provide both numbers to document instances in which the sample numbers in the lab files differ from the field sample number.

    LATITUDE
    Latitude, WGS 84 (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:62.568967
    Maximum:63.221415
    Units:decimal degrees

    LONGITUDE
    Longitude, WGS 84 (Source: Alaska Division of Geological & Geophysical Surveys)

    Range of values
    Minimum:-148.807913
    Maximum:-145.948239
    Units:decimal degrees

    DESCRIPTION
    Description of the sample (Source: Alaska Division of Geological & Geophysical Surveys)

    Characters 1 to 254 of a brief sample or station description.

    DESCRIP_2
    Extension of the sample or station description for descriptions which are greater than 254 characters in length (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLBlank (NULL) values indicate that the descriptive text is shorter than 254 characters.

    Characters greater than 254 of the sample or station description.

    DATED_MATERIAL
    Indicates the type of material that was used for analysis (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The type of material that was selected for dating varied according to mineral composition and grainsize of the submitted rock sample. This field specifies whether the age was derived from a mineral separate (generally 1 to 10 individual crystals dated together as a single run), a single crystal, or the whole rock.

    MINERAL
    Indicates the mineral that was used for analysis (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The minerals selected for dating would typically be grains of biotite, hornblende, or muscovite.

    INTEGRATED_AGE_MA
    Integrated age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The values are a concatenation of the integrated age determination and the calculated error associated with the integrated age determination

    PLATEAU_AGE_MA
    Plateau age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The values are a concatenation of the plateau age determination and the calculated error associated with the plateau age determination

    PLATEAU_PERCENT_39AR
    Value in percent of the 39 Ar used in that portion of the spectrum to determine the plateau age (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:46.9
    Maximum:94.6
    Units:percent

    PLATEAU_MSWD
    The mean square weighted deviation of the plateau age calculation (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.75
    Maximum:4.29

    PLATEAU_REMARKS
    Comments and additional values that pertain to the plateau age determination method or interpretation. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Free text

    ISOCHRON_AGE
    Isochon age and age error in million years (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the ISOCHRON_AGE value was not provided by the lab

    ISOCHRON_MSWD
    The mean square weighted deviation of the isochron age calculation (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the value was not calculated by the lab

    ISOCHRON_REMARKS
    Comments and additional values that pertain to the isochon age determination method or interpretation. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the ISOCHRON_REMARKS value was not provided by the lab

    PREFERRED
    Indicates preferred age. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    A discussion of the preferred age for each analysis is provided in the accompanying lab report. The possible values are: plateau, isochron, or integrated.

    LAB_NOTES
    Additional information provided by the lab (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Free text

    rdf2014-18-step-heating-data.csv
    Power output levels and resultant measurements from each sample run (Source: Alaska Division of Geological & Geophysical Surveys)

    SAMPLE
    Label assigned in the field to identify the sample. (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a sample identifier: YYAAA9999X: YY=last two digits of year, AAA=geologist's initials (one to three characters), 9999=unique station number, X= optional alpha character which indicates that multiple samples were collected at a given location or that multiple observations were recorded in the project database. The initials used by the geologists who collected samples for this project are: ET = Evan Twelker, LF = Larry K. Freeman and RN = Rainer J. Newberry

    LAB_SAMPLE_NUMBER
    Label used by the lab to identify the sample. (Source: Alaska Division of Geological & Geophysical Surveys and Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    The lab sample number is typically identical to the field sample number. However, in some cases, the sample number provided by the lab does differ from the number assigned in the field. We provide both numbers to document instances in which the sample numbers in the lab files differ from the field sample number.

    Laser_mW
    Laser output level in megawatts (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the values in the row were calculated by weighting the individual heating steps by the fraction of 39Ar released.

    Range of values
    Minimum:400
    Maximum:9000
    Units:megawatts

    Integrated
    We indicate whether the values in the row were derived from a heating step or calculated by weighting the individual heating steps by the fraction of 39Ar released. (Source: Alaska Division of Geological & Geophysical Surveys)

    ValueDefinition
    NULLThe values in the row were derived from a heating step
    Integratedthe values in this row were calculated by weighting the individual heating steps by the fraction of 39Ar released

    Cum39Ar
    Cumulative ratio of 39Argon released at this step (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    ValueDefinition
    NULLA NULL or blank values indicates that the value was not applicable or not calculated by the lab

    Range of values
    Minimum:0.0014
    Maximum:1

    Me40Ar39Ar
    Measured 40Ar/39Ar ratio for each heating step, corrected for blank and 39Ar decay (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:18.78885
    Maximum:2508.2839

    Er40Ar39Ar
    The one sigma error for each 40Ar/39Ar measurement (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.0256
    Maximum:161.30494

    Me37Ar39Ar
    The ratio of measured 37Ar to measured 39Ar for each heating interval for each sample corrected for blank and 37Ar and 39Ar decay (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.00658
    Maximum:29.38999

    Er37Ar39Ar
    The one sigma error for each 37Ar/39Ar measurement (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.00074
    Maximum:0.43729

    Me36Ar39Ar
    Ratio of measured 36Ar to measured 39Ar for each step interval for each sample corrected for blank and 39Ar decay (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:-0.00162
    Maximum:7.9404

    Er36Ar39Ar
    The one sigma error for each 36Ar/39Ar measurement (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.00013
    Maximum:0.51505

    Atm40Ar
    Percent of 40Ar which is atmospheric in composition at each step level (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:-2.29196
    Maximum:98.30294

    MeCaK
    Ratio of Calcium to Potassium as determined from 37Ar/39Ar (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.01208
    Maximum:55.06959

    ErCaK
    The one sigma error for each Ca/K determination (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.00136
    Maximum:0.80998

    MeClK
    Ratio of Chlorine to Potassium as determined from 38Ar/39Ar (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.00243
    Maximum:0.94538

    ErClK
    The one sigma error for each Cl/K determination (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.00005
    Maximum:0.06149

    Ar40Rad39ArK
    Ratio of radiogenic 40Ar to 39Ar derived from potassium (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:5.30942
    Maximum:163.18502

    Er40ArRad39ArK
    One sigma error for each 40ArRad/39ArK value (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.0442
    Maximum:24.19149

    AgeMa
    Calculated age for each temperature step for each sample (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:31.39
    Maximum:778.17
    Units:MA

    ErAgeMa
    One sigma error of the age determination of each heating step (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    Range of values
    Minimum:0.41
    Maximum:93.68
    Units:MA

    WeightedAverageOfJFromStandards
    J value, calculated from the weighted average of standards placed in various positions in the nuclear reactor (Source: Geochronology Laboratory at the University of Alaska Fairbanks (UAF))

    WeightedAverageOfJFromStandards value and error

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?

    This project is funded through the Governor's Strategic and Critical Minerals Assessment Capital Improvement Project, a component of the ongoing Alaska Airborne Geophysical/Geological Mineral Inventory Program funded by the Alaska State Legislature and managed by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.

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

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

    (907)451-5020 (voice)
    dggsgis@alaska.gov

    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays

Why was the data set created?

Mineral-resources geologists from the Alaska Division of Geological & Geophysical Surveys (DGGS) carried out a helicopter-supported geological and geochemical resource assessment project in the Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles from July 29 through August 16, 2013. The objectives of this assessment were to improve the publicly-available geological, geophysical, and geochemical data in the area of known mineral occurrences in the Mount Hayes Quadrangle, and to extend this coverage and any insight gained westward into the less-explored extension of the Wrangellia terrane. A subset of rock samples was selected for 40Ar/39Ar age dating to allow us to better characterize and distinguish plutonic complexes and mineralization events, and to unravel the magmatic, structural, and metallogenic evolution of the area.

How was the data set created?

  1. From what previous works were the data drawn?

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

    Date: 2013 (process 1 of 3)
    Fieldwork - Field geologists collected rock samples from surface outcrops. Care was taken to collect fresh, unweathered samples displaying, when possible, sufficiently large grains for mineral separate sampling.

    Date: 2013 (process 2 of 3)
    Sample preparation and analysis - Prior to processing, thin sections of the samples were petrographically inspected to ensure that mineral specimens selected for dating were free of alteration. Rock samples that we found to be suitable for dating by 40Ar/39Ar geochronology analysis were submitted to the Geochronology Laboratory at the University of Alaska Fairbanks (UAF) where they were dated according to the protocols outlined in the accompanying report.

    Date: 2014 (process 3 of 3)
    Tables were modified to better distinguish between plateau and weighted average ages.

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

    Twelker, Evan, Bachmann, E.N., Freeman, L.K., Newberry, R.J., Reioux, D.A., Sicard, K.R., Tuzzolino, A.L., Wright, T.C., and Wypych, Alicja, 2014, Major-oxide, minor-oxide, and trace-element geochemical data from rocks and stream sediments in the Wrangellia mineral assessment area, Gulkana, Healy, Mount Hayes, and Talkeetna Mountains quadrangles, Alaska: Raw Data File RDF 2014-3, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 6 p

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

  1. How well have the observations been checked?

    Coordinates of sample locations were determined by the geologists in the field using handheld GPS units. Sample numbers were recorded in the field on sample bags and on field note sheets. The sample location table was cross checked for consistency against the sample numbers recorded on the bags. Laboratory sample numbers were generated by the UAF geochronology lab from the a list provided by DGGS. See text report for additional discussion of laboratory procedures. Lab results and interpretations were examined by the DGGS geologists to ensure that they are reasonable given the geologic context of the sample.

  2. How accurate are the geographic locations?

    Location coordinates (WGS84 datum) were collected using handheld GPS units, with a typical reported accuracy of about 10 m.

  3. How accurate are the heights or depths?

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

    Users should note that the interpretive summaries that are provided in the text report have been lightly edited for clarity but are generally provided as received.

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

    No topologic relationships are present in the data. We plotted the data points using GIS software to ensure that they are correctly located and we visually reviewed the sample identification numbers and other attribute values to ensure that they are free of typological errors.

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 is 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. The 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. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data 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 or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.

  1. Who distributes the data set? (Distributor 1 of 1)

    Alaska Division of Geological & Geophysical Surveys
    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 website (<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?

    RDF 2014-18

  3. What legal disclaimers am I supposed to read?

    The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data 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 or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor 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: 05-Dec-2014
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Metadata Manager
3354 College Road
Fairbanks, AK 99709-3707
USA

(907)451-5020 (voice)

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

Generated by mp version 2.9.21 on Fri Dec 5 14:23:59 2014