40Ar/39Ar data, Alaska Highway corridor from Delta Junction to Canada border, parts of Mount Hayes, Tanacross, and Nabesna quadrangles, Alaska

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Frequently anticipated questions:

What does this data set describe?

Title:
40Ar/39Ar data, Alaska Highway corridor from Delta Junction to Canada border, parts of Mount Hayes, Tanacross, and Nabesna quadrangles, Alaska
Abstract:
40Ar/39Ar analyses of igneous rocks from the Alaska Highway corridor between Delta Junction and the Canada border show a range of Cretaceous ages from about 68 Ma to about 112 Ma. The 25 samples fall into two broad age groups. The younger group ranges from about 68 Ma to 73 Ma; the older group ranges from a minimum age of about 84 Ma to about 103 Ma. One sample, a mafic dike, yielded an older age of about 112 Ma.
Supplemental_Information:
The dated materials vary by sample and, in many cases, multiple minerals or mineral separates were analyzed from each rock sample. The three tables presented in this release are organized according to the hierarchy of data. We provide the location and description of each rock; summary age determination for each dated rock, mineral grain, or mineral separate; and the analytical measurements generated by each heating step. The values in the fields: Sample_Id and Lab_Sample_Number are used within the tables and the report to cross reference rock sample and laboratory sample records. 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 the metadata or 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: 
sample-location-details:    Identification numbers, GPS coordinates, and description of each sample. 
step-heating-data:    The root 40Ar/39Ar analytical data table. This file lists the power output levels and resultant measurements from each sample run. 
interpretive-details:    Summary of 40Ar/39Ar radiometric ages of samples in this report and other interpretive details.
  1. How should this data set be cited?

    Solie, D.N., Layer, P.W., Werdon, M.B., Newberry, R.J., Freeman, L.K., and Lessard, R.R., 2013, 40Ar/39Ar data, Alaska Highway corridor from Delta Junction to Canada border, parts of Mount Hayes, Tanacross, and Nabesna quadrangles, Alaska: Raw Data File RDF 2013-8, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 35 p.

  2. What geographic area does the data set cover?

    West_Bounding_Coordinate: -144.728390
    East_Bounding_Coordinate: -141.359559
    North_Bounding_Coordinate: 63.841939
    South_Bounding_Coordinate: 62.902474

  3. What does it look like?

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

    Beginning_Date: 2009
    Ending_Date: 2013
    Currentness_Reference: publication date

  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?

      The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is North American Datum of 1927.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.9786982.

  7. How does the data set describe geographic features?

    rdf2013-8-sample-location-details.csv
    Identification numbers, GPS coordinates, and description of each sample. (Source: Alaska Division of Geological & Geophysical Surveys)

    Sample_Id
    Label assigned to identify the field location where a sample was collected and to identify the sample in related project publications. (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a station identifier: 20YYAAA9999X: 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: RL = Lessard, R.R.; MBW = Werdon, M.B.; DNS = Solie, D.N.; RN = Newberry, R.J.; LF = Freeman, L.K.

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

    Range of values
    Minimum:62.902474
    Maximum:63.841939

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

    Range of values
    Minimum:-144.72839
    Maximum:-141.359559

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

    A brief sample description; note that the values in this field may exceed 255 characters

    rdf2013-8-step-heating-data.csv
    The root 40Ar/39Ar analytical data table. This file lists the power output levels and resultant measurements from each sample run. (Source: Alaska Division of Geological & Geophysical Surveys)

    Sample_Id
    Label assigned to identify the field location where a sample was collected and to identify the sample in related project publications. (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a station identifier: 20YYAAA9999X: 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: RL = Lessard, R.R.; MBW = Werdon, M.B.; DNS = Solie, D.N.; RN = Newberry, R.J.; LF = Freeman, L.K.

    Lab_Sample_Number
    Sample identifier assigned by the laboratory, note that these numbers correspond to spectra plot labels provided in the appendix of the text report (Source: University of Alaska Fairbanks Geochronology Laboratory)

    Lab numbers generally combine the DGGS sample number and the name of the dated mineral, but they do not follow a specific naming convention.

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

    ValueDefinition
    Integrated"Integrated" values in the Laser_mW column indicate that this row provides the age and errors given by the total gas measured and the values are equivalent to a potassium-argon (K-Ar) age.

    Range of values
    Minimum:300
    Maximum:9000
    Units:megawatts

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

    ValueDefinition
    NULLBlank (NULL) field values indicate that a value was not provided by the lab.

    Range of values
    Minimum:0.0025
    Maximum:1

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

    Range of values
    Minimum:7.7367
    Maximum:427.3728

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

    Range of values
    Minimum:0.026
    Maximum:9.8057

    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: University of Alaska Fairbanks Geochronology Laboratory)

    Range of values
    Minimum:-0.0009
    Maximum:119.75993

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

    Range of values
    Minimum:0.0001
    Maximum:2.98741

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

    Range of values
    Minimum:-0.0764
    Maximum:1.32089

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

    Range of values
    Minimum:0
    Maximum:0.06435

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

    Range of values
    Minimum:-199.3
    Maximum:111.3
    Units:percent

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

    Range of values
    Minimum:-0.0016
    Maximum:240.0451

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

    Range of values
    Minimum:0.0002
    Maximum:6.5411

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

    Range of values
    Minimum:-0.00116
    Maximum:0.2019

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

    Range of values
    Minimum:0
    Maximum:0.01822

    40ArRad39ArK
    Ratio of radiogenic 40Ar to 39Ar derived from potassium (Source: University of Alaska Fairbanks Geochronology Laboratory)

    Range of values
    Minimum:-5.325
    Maximum:37.1353

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

    Range of values
    Minimum:0.03
    Maximum:19.2562

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

    Range of values
    Minimum:-36.2
    Maximum:234.2
    Units:Ma

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

    Range of values
    Minimum:0.2
    Maximum:128.9
    Units:Ma

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

    ValueDefinition
    2.666e-03 ± 1.336e-050.002666 ± 0.00001336
    3.733e-03 ± 1.265e-050.003733 ± 0.00001265
    3.578e-03 ± 1.111e-050.003578 ± 0.00001111
    3.411e-03 ± 1.051e-050.003411 ±0.00001051
    3.463e-03 ± 1.087e-050.003463 ± 0.00001087

    rdf2013-8-interpretive-details.csv
    Summary of 40Ar/39Ar radiometric ages of samples in this report and other interpretive details. (Source: Alaska Division of Geological & Geophysical Surveys)

    Sample_Id
    Label assigned to identify the field location where a sample was collected and to identify the sample in related project publications. (Source: Alaska Division of Geological & Geophysical Surveys)

    Generic example of a station identifier: 20YYAAA9999X: 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: RL = Lessard, R.R.; MBW = Werdon, M.B.; DNS = Solie, D.N.; RN = Newberry, R.J.; LF = Freeman, L.K.

    Dated_Material
    Indicates the type of material that was used for analysis (Source: University of Alaska Fairbanks Geochronology Laboratory)

    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: University of Alaska Fairbanks Geochronology Laboratory)

    The minerals selected for dating were: biotite, hornblende, or muscovite.

    Lab_Sample_Number
    Sample identifier assigned by the laboratory, note that these numbers correspond to spectra plot labels provided in the appendix of the text report (Source: University of Alaska Fairbanks Geochronology Laboratory)

    Lab numbers generally combine the DGGS sample number and the name of the dated mineral, but they do not follow a specific naming convention.

    Integrated_Age_Ma
    Integrated age and age error in million years (Source: University of Alaska Fairbanks Geochronology Laboratory)

    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: University of Alaska Fairbanks Geochronology Laboratory)

    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: University of Alaska Fairbanks Geochronology Laboratory)

    ValueDefinition
    NULLBlank (NULL) field values indicate that a value was not provided by the lab.

    Range of values
    Minimum:17.8
    Maximum:99
    Units:percent

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

    ValueDefinition
    NULLBlank (NULL) field values indicate that a value was not provided by the lab.

    Range of values
    Minimum:0.03
    Maximum:26

    Plateau_Remarks
    Comments and additional values that pertain to the plateau age determination method or interpretation. (Source: University of Alaska Fairbanks Geochronology Laboratory)

    Free text

    Isochron_Age
    Isochon age and age error in million years (Source: University of Alaska Fairbanks Geochronology Laboratory)

    ValueDefinition
    NULLBlank (NULL) field values indicate that a 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: University of Alaska Fairbanks Geochronology Laboratory)

    ValueDefinition
    NULLBlank (NULL) field values indicate that a value was not provided by the lab.

    Range of values
    Minimum:0.17
    Maximum:2.6

    Isochron_Remarks
    Comments and additional values that pertain to the isochron age determination method or interpretation. (Source: University of Alaska Fairbanks Geochronology Laboratory)

    Free text

    Lab_Notes
    Additional information provided by the lab (Source: University of Alaska Fairbanks Geochronology Laboratory)

    Free text

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 was supported by Alaska State Capital Improvement Project funding. Partial funding for mapping and 40Ar/39Ar geochronology in the Mt. Hayes C-1, C-2, D-1, and D-2 quadrangles was also provided through the U.S. Geological Survey STATEMAP program under award number 07HQAG0076. Samples in this report were collected by Larry Freeman, Melanie Werdon, Richard Lessard, and Diana Solie of DGGS, and Rainer Newberry of University of Alaska Fairbanks Department of Geology & Geophysics.

  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?

Alaska Division of Geological & Geophysical Surveys (DGGS) personnel collected rock samples while mapping the bedrock geology along the Alaska Highway corridor between Delta Junction and the Canada border. The purpose of this DGGS Raw Data File is to present the 40Ar/39Ar results of samples that were selected for age dating and make them available for use to the public. This data release is one component of a multi-year DGGS project studying the geology, geohazards and resources along the proposed gas pipeline corridor.

How was the data set created?

  1. From what previous works were the data drawn?

    Lanphere, M.A. and Dalrymple, G.B., 2000 (source 1 of 6)
    Lanphere, M.A., and Dalrymple, G.B., 2000, First-principles calibration of 38Ar tracers :implications for the ages of 40Ar/39Ar fluence monitors: Professional Paper P 1621, U.S. Geological Survey, United States.

    Online Links:

    Other_Citation_Details: 10 p
    Type_of_Source_Media: paper
    Source_Contribution: sample preparation

    Samson, S.D. and Alexander, E.C., 1987 (source 2 of 6)
    Samson, S.D., and Alexander, E.C., 1987, Calibration of the inter-laboratory 40Ar/39Ar dating standard, MMhb-1: Isotope Geoscience Section v. 66, European Association of Geochemistry, Netherlands.

    Type_of_Source_Media: paper
    Source_Contribution: sample preparation

    York, Derek and others, 1981 (source 3 of 6)
    York, Derek, Hall, C.M, Yanase, Yotaro, and Hanes, J.A, 1981, 40Ar/39Ar dating of terrestrial minerals with a continuous laser: Geophysical Research Letters v. 8, n. 11, American Geophysical Union, United States.

    Type_of_Source_Media: paper
    Source_Contribution: sample analysis

    Layer, P.W and others, 1987 (source 4 of 6)
    Layer, P.W, Hall, C.M, and York, Derek, 1987, The derivation of 40Ar/39Ar age spectra of single grains of hornblende and biotite by laser step-heating: Geophysical Research Letters v. 14, n. 7, American Geophysical Union, United States.

    Type_of_Source_Media: paper
    Source_Contribution: sample analysis

    Layer, P.W, 2000 (source 5 of 6)
    Layer, P.W, 2000, Argon-40/Argon-39 age of the El'gygytgyn impact event, Chukotka, Russia: Meteroritics and Planetary Science v. 35, n. 3, Meteoritical Society, United States.

    Type_of_Source_Media: paper
    Source_Contribution: sample analysis

    McDougall, Ian and Harrison, T.M, 1999 (source 6 of 6)
    McDougall, Ian, and Harrison, T.M, 1999, Geochronology and thermochronology by the 40Ar/39Ar method, 2nd ed.: Oxford University Press, United States.

    Type_of_Source_Media: paper
    Source_Contribution: sample analysis

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

    Date: 2009 (process 1 of 3)
    Fieldwork - Field geologists collected rock samples from the surface or within 0.5 m of the surface. Care was taken to collect fresh, unweathered samples representative of igneous rock types in the map area. Locations were recorded using handheld GPS units with an estimated horizontal accuracy of approximately 10 m. Samples were collected during the 2006 through 2009 field seasons.

    Date: 2010 (process 2 of 3)
    Sample preparation - The selected rock samples were submitted to the University of Alaska Fairbanks Geochronology Laboratory. There the samples were crushed, washed, and sieved to either 100-250 or 250-500 micron size fractions, and hand-picked for date-able mineral phases. The monitor mineral MMhb-1 (Samson, S.D. and Alexander, E.C., 1987) with an age of 513.9 Ma (Lanphere, M.A. and Dalrymple, G.B., 2000) was used to monitor neutron flux (and calculate the irradiation parameter, J). The samples and standards were wrapped in aluminum foil and loaded into aluminum cans of 2.5 cm diameter and 6 cm height. The samples were irradiated in position 5c of the uranium-enriched research reactor of McMaster University in Hamilton, Ontario, Canada, for 20 megawatt-hours.

    Data sources used in this process:

    • Lanphere, M.A. and Dalrymple, G.B., 2000
    • Samson, S.D. and Alexander, E.C., 1987

    Date: 2010 (process 3 of 3)
    Sample analysis - Upon their return from the reactor, the samples and monitors were loaded into 2-mm-diameter holes in a copper tray that was then loaded in an ultra-high-vacuum extraction line. The monitors were fused, and samples heated, using a 6-watt argon-ion laser following the technique described in York and others (1981), Layer and others (1987), and Layer (2000). Argon purification was achieved using a liquid nitrogen cold trap and a SAES Zr-Al getter at 400 degrees C. The samples were analyzed in a VG-3600 mass spectrometer at the Geophysical Institute, University of Alaska Fairbanks. The argon isotopes measured were corrected for system blank and mass discrimination, as well as calcium, potassium, and chlorine interference reactions following procedures outlined in McDougall and Harrison (1999). See text report for additional description of the analytical procedures, parameters, and a comprehensive bibliography.

    Data sources used in this process:

    • York, Derek and others, 1981
    • Layer, P.W and others, 1987
    • Layer, P.W, 2000
    • McDougall, Ian and Harrison, T.M, 1999

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

    Carver, G.A., Bemis, S.P., Solie, D.N., Castonguay, S.R., and Obermiller, K.E., 2010, Active and potentially active faults in or near the Alaska Highway corridor, Dot Lake to Tetlin Junction, Alaska: Preliminary Interpretive Report PIR 2010-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 42 p
    Carver, G.A., Bemis, S.P., Solie, D.N., and Obermiller, K.E., 2008, Active and potentially active faults in or near the Alaska Highway corridor, Delta Junction to Dot Lake, Alaska: Preliminary Interpretive Report PIR 2008-3D, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 32 p
    Hubbard, T.D., and Reger, R.D., 2010, Engineering - geologic map of the Alaska Highway corridor, Robertson River to Tetlin Junction, Alaska: Preliminary Interpretive Report PIR 2009-6B, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 4 sheets, scale 1:63,360
    Hubbard, T.D., Reger, R.D., and Gallagher, P.E., 2013, Engineering - geologic map of the Alaska Highway corridor, Tetlin Junction to Canada border, Alaska: Preliminary Interpretive Report PIR 2012-1B, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 2 sheets, scale 1:63,360
    Koehler, R.D., and Carver, G.A., 2012, Active and potentially active faults along the Alaska Highway corridor, Tetlin Junction to the Canada border: Preliminary Interpretive Report PIR 2012-2, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 23 p
    Koehler, R.D., and Woods, R.-E.F., 2013, Paleoseismic and LiDAR investigations along the Cathedral Rapids and Dot "T" Johnson faults, interior Alaska: Report of Investigation RI 2013-4, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 21 p
    Reger, R.D., and Hubbard, T.D., 2010, Reconnaissance interpretation of 1978-1983 permafrost, Alaska Highway corridor, Robertson River to Tetlin Junction, Alaska: Preliminary Interpretive Report PIR 2009-6C, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 13 p., 4 sheets, scale 1:63,360
    Reger, R.D., and Solie, D.N., 2008, Engineering - geologic map, Alaska Highway corridor, Delta Junction to Dot Lake, Alaska: Preliminary Interpretive Report PIR 2008-3B, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 2 sheets, scale 1:63,360
    Reger, R.D., and Solie, D.N., 2008, Reconnaissance interpretation of permafrost, Alaska Highway corridor, Delta Junction to Dot Lake, Alaska: Preliminary Interpretive Report PIR 2008-3C, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p., 2 sheets, scale 1:63,360
    Reger, R.D., Hubbard, T.D., and Carver, G.A., 2011, Surficial geology of Alaska Highway corridor, Robertson River to Tetlin Junction, Alaska: Preliminary Interpretive Report PIR 2009-6A, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 53 p., 4 sheets, scale 1:63,360
    Reger, R.D., Hubbard, T.D., and Gallagher, P.E., 2012, Reconnaissance interpretation of 1978-1981 permafrost, Alaska Highway corridor, Tetlin Junction to Canada border, Alaska: Preliminary Interpretive Report PIR 2012-1C, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 27 p., 2 sheets, scale 1:63,360
    Reger, R.D., Hubbard, T.D., and Gallagher, P.E., 2012, Surficial geology of the Alaska Highway corridor, Tetlin Junction to Canada border, Alaska: Preliminary Interpretive Report PIR 2012-1A, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 25 p., 2 sheets, scale 1:63,360
    Reger, R.D., Stevens, D.S.P., and Solie, D.N., 2008, Surficial-geologic map, Delta Junction to Dot Lake, Alaska Highway corridor: Preliminary Interpretive Report PIR 2008-3A, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 48 p., 2 sheets, scale 1:63,360
    Solie, D.N., Werdon, M.B., Newberry, R.J., Freeman, L.K., and Lessard, R.R., 2008, Major-oxide, minor-oxide, trace-element and geochemical data from rocks collected in the Alaska Highway corridor Mount Hayes Quadrangle, Alaska in 2006 and 2007: Raw Data File RDF 2008-2 v. 1.0.1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 23 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 numbers were transcribed into an Access database by a field assistant. The sample location table was generated from the database and 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?

    Coordinates of sample locations were determined by the geologists in the field using handheld GPS units. Estimated position errors calculated by GPS units averaged approximately 6 meters.

  3. How accurate are the heights or depths?

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

    These analyses were completed throughout the duration of the project and subsequently compiled into a single report. 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. In a few cases the lab did not specifically record the type of dated material (mineral separate versus single grain). Based on subsequent personal correspondence with lab staff, we indicate that the dated material type is "mineral separate" for all samples that were not explicitly described as single grain or whole rock within the text report.

  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 2013-8

  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: 07-Jan-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 Tue Jan 7 12:22:08 2014