Identification_Information: Citation: Citation_Information: Originator: Layer, P.W. Originator: Solie, D.N. Publication_Date: 2008 Title: 40Ar/39Ar ages from the Tyonek D-6 quadrangle and parts of Tyonek D-7, Tyonek D-5 and Tyonek C-6 quadrangles, Alaska Geospatial_Data_Presentation_Form: tabular digital data Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2008-4 Publication_Information: Publication_Place: Fairbanks, Alaska - USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Other_Citation_Details: 14 pp. Online_Linkage: http://dx.doi.org/10.14509/16521 Description: Abstract: 40Ar/39Ar data from plutonic and volcanic samples collected during preliminary mapping of the Tyonek D-6 and parts of Tyonek D-5, D-7 and C-6 quadrangles yield results indicating three discrete igneous events at about 55, 60 and 68 Ma. Igneous clasts from a boulder conglomerate retain Early Cretaceous ages. Purpose: In 1990, DGGS conducted a preliminary geologic mapping project in the Tyonek D-6 and parts of the adjacent D-5, D-7 and C-6 quadrangles. DGGS published a preliminary geologic map and geochemical data resulting from that initial work in 1991 (Solie and others, 1991a and 1991b). At that time, the results from the 40Ar/39Ar age dating were pending. A brief discussion of the results was given in Layer and Solie (1991) and Solie and Layer (1993). The purpose of this DGGS Raw Data File is to present the 40Ar/39Ar results and make them available for use to others interested in the area. Supplemental_Information: Attribute information for the following tables (entities) is included in this metadata file under the "Entity_and_Attribution_Information" section. The tables are as follows: >Table1_coordinates Coordinates for 40Ar/39Ar samples >Table2_agesummary Summary table for 40Ar/39Ar data >Table3_analyticaldata The 40Ar/39Ar analytical data associated with each recorded temperature Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 1990 Ending_Date: 1991 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -152.3361 East_Bounding_Coordinate: -151.8734 North_Bounding_Coordinate: 61.9254 South_Bounding_Coordinate: 61.6924 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: geoscientificInformation Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: Geology Theme_Keyword: 40Ar/39Ar Theme_Keyword: Age Dates Theme_Keyword: Geochronology Place: Place_Keyword_Thesaurus: None Place_Keyword: Tyonek Quadrangle Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: Cretaceous Temporal_Keyword: Paleocene Temporal_Keyword: Early Cretaceous Access_Constraints: This report 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. 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Contact_Position: GIS Data Manager/Cartographer Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Contact_Voice_Telephone: (907) 451-5029 Contact_Voice_Telephone: (907) 451-5020 Contact_Facsimile_Telephone: (907) 451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Contact_Instructions: You may view our web site at http://www.dggs.alaska.gov 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. Data_Set_Credit: This research was supported by State funding to the Alaska Division of Geological & Geophysical Surveys. Additional Acknowledgments: 1990 DGGS field mapping and sample collection by DN. Solie, J.T. Kline (deceased), W.G. Gilbert, E.E. Harris, M.S. Robinson, S.A. Liss and K.K. DePalma. Review of draft manuscript by D.J. Szumigala. Native_Data_Set_Environment: Microsoft Windows XP SP2, Microsoft Excel 2003 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: All field locations were visually determined by the geologists in the field and recorded on a 1:63,360 topographic map enlarged to a scale of 1:40,000. Coordinates were digitized visually from the field maps. DGGS submitted fourteen rock samples to the UAF Geochronology Laboratory for 40Ar/39Ar dating. Major oxide and selected trace element analyses for most of the samples are included in Solie and others (1991b). Separates for 40Ar/39Ar dating were prepared to >99.5% purity (visual inspection) using standard heavy liquid and magnetic separation techniques followed by hand-picking under a binocular microscope. Thin section examination of the samples prior to crushing indicated that the chosen minerals were free from alteration and sufficiently coarse-grained for mechanical separation. For all minerals, grains in the size range of 250 - 500 microns were used. For each sample, ~50-80 mg of biotite or 250-350 mg of hornblende or whole rock (phenocryst-free groundmass) was packaged in an aluminum foil tube and irradiated in position 5C at the McMaster University nuclear reactor, in Hamilton, Ontario. Approximately 20 samples were irradiated at a time. Six packages containing ~20 mg of the standard mineral mmhb-1 (Samson and Alexander, 1987) with an age of 513.9 Ma (Lanphere and others, 1990) were also irradiated with the samples to determine the irradiation parameter (J) and the flux gradient in the reactor. Samples and standards were analyzed 45 to 90 days after irradiation. The irradiated samples were step-heated on-line in a Modifications Ltd. low-blank furnace. Temperature control was better than 5 degrees and a maximum temperature in excess of 1600o C was achievable to ensure complete sample fusion. The extracted argon was purified in a two-stage process using a liquid nitrogen cold finger and two SAES Zr-Al getters. Prior to measurement of the Ar, the gas was collected on an activated charcoal finger. The purified Ar gas was measured using a Nuclide 6-60-SGA 15 cm mass spectrometer. The sensitivity of the spectrometer is 6.5 x 10-15 mol/mV and system noise is generally around 0.02 mV. System blanks are generally better than 1 X 10-14 mol for 40Ar. Argon isotopic measurements for both samples and standards were corrected for the system blanks, for decay of 37Ar and 39Ar, and for reactor-induced isotopic interferences. Ages were calculated using the equations and corrections from McDougall and Harrison (1999) and the constants from Steiger and Jaeger (1977) and are shown in Table 2 (age summary) and Table 3 (analytical data). All errors on analyses are reported at the 1-sigma level. For each mass spectrometer analysis, five Ar isotope abundances are measured. 36Ar is used to determine the amount of atmospheric or initial Ar in the sample, 37Ar provides an estimation of the Ca content in the mineral, 38Ar provides an estimation of the Cl content, 39Ar reflects the K content and 40Ar is a mixture of initial and radiogenic Ar. The age of the sample is proportional to the ratio of the amount of radiogenic 40Ar to the amount of 39Ar produced by neutron bombardment from 40K. Logical_Consistency_Report: No topologic relationships are present in the data. Completeness_Report: This dataset includes all of the samples submitted for 40Ar/39Ar age date analyses from the Tyonek quadrangle which were collected by DGGS during the summer of 1990. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Sample locations were determined visually by geologist in the field, using a Brunton compass and altimeter and topographic map. Locations were then digitized visually from the field maps using ArcGIS v9.2. Quantitative_Horizontal_Positional_Accuracy_Assessment: Horizontal_Positional_Accuracy_Value: 100 Horizontal_Positional_Accuracy_Explanation: The sample locations were found in the field using a compass and altimeter. Considering the errors inherent in the USGS topographic maps, locating oneself in the field, and the methods of digitizing stations, samples are located to an accuracy of between 10 and 100 meters. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Lanphere, M.A. Originator: Dalrymple, G.B. Originator: Fleck, R.J. Originator: Pringle, M.S. Publication_Date: 1990 Title: Intercalibration of mineral standards for K/Ar and 40Ar/39Ar age measurements Geospatial_Data_Presentation_Form: journal article Series_Information: Series_Name: EOS Transactions of the American Geophysical Union Issue_Identification: v. 71 Other_Citation_Details: (abstract), P. 1658 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1990 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Lanphere and others, 1990 Source_Contribution: Describes intercalibration standards Source_Information: Source_Citation: Citation_Information: Originator: Layer, P.W. Originator: Solie, D.N. Publication_Date: 1991 Title: Timing of igneous activity and basin formation, southern Alaska Range, as constrained by 40Ar/39Ar dating Geospatial_Data_Presentation_Form: journal article Series_Information: Series_Name: EOS Transactions of the American Geophysical Union Issue_Identification: v.72, no. 44 Other_Citation_Details: (abstract), p. 503 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1991 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Layer and Solie, 1991 Source_Contribution: Abstract discussing age results Source_Information: Source_Citation: Citation_Information: Originator: McDougall, I Originator: Harrison, T.M. Publication_Date: 1999 Title: Geochronology and Thermochronology by the 40Ar/39Ar method Edition: 2 Geospatial_Data_Presentation_Form: book chapter Publication_Information: Publication_Place: Oxford Publisher: Oxford University Press Other_Citation_Details: 269 pp. Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1999 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: McDougall and others, 1999 Source_Contribution: Source reference for equations and corrections used in age calculation. Source_Information: Source_Citation: Citation_Information: Originator: Samson, S.D. Originator: Alexander, E.C. Publication_Date: 1987 Title: Calibration of the interlaboratory 40Ar/39Ar dating standard, MMhb-1 Geospatial_Data_Presentation_Form: document Series_Information: Series_Name: Chemical Geology Issue_Identification: v. 66 Other_Citation_Details: p. 27-34 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1987 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Samson and Alexander, 1987 Source_Contribution: Interlaboratory calibration data for age determination Source_Information: Source_Citation: Citation_Information: Originator: Solie, D.N. Originator: Kline, J.T. Originator: Gilbert, W.G. Originator: Robinson, M.S. Originator: Harris, E.E. Originator: Liss, S.A. Publication_Date: 1991 Title: Analytical results from rock and pan concentrate samples, Tyonek D-6 and parts of adjacent quadrangles, Alaska Geospatial_Data_Presentation_Form: document Series_Information: Series_Name: Public Data File Issue_Identification: PDF 91-1 Other_Citation_Details: 14 pp., 1 sheet, scale 1:63,360 Online_Linkage: http://dx.doi.org/10.14509/1468 Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1991 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Solie and others, 1991b Source_Contribution: Geochemical data from samples collected from project area; sample location map Source_Information: Source_Citation: Citation_Information: Originator: Solie, D.N. Originator: Gilbert, W.G. Originator: Harris, E.E. Originator: Kline. J.T. Originator: Liss, S.A. Originator: Robinson, M.S. Publication_Date: 1991 Title: Preliminary geologic map of Tyonek d-6 and eastern Tyonek D-7 quadrangles, Alaska Geospatial_Data_Presentation_Form: document Series_Information: Series_Name: Public Data File Issue_Identification: PDF 91-10 Other_Citation_Details: 16 pp., 1 sheet, scale 1:40,000 Online_Linkage: http://dx.doi.org/10.14509/1477 Type_of_Source_Media: online Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1991 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Solie and others, 1991a Source_Contribution: Preliminary map of project area Source_Information: Source_Citation: Citation_Information: Originator: Solie, D.N. Originator: Layer, P.W. Publication_Date: 1993 Title: The Hayes Glacier Fault, southern Alaska Range: Evidence for post-paleocene movement Geospatial_Data_Presentation_Form: map Series_Information: Series_Name: Professional Report Issue_Identification: PR 106 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Other_Citation_Details: p. 71-80 Online_Linkage: http://dx.doi.org/10.14509/2312 Larger_Work_Citation: Citation_Information: Originator: Solie, D.N. Originator: Tannian, Fran Publication_Date: 1993 Title: Short Notes on Alaskan Geology 1993 Series_Information: Series_Name: Professional Report Issue_Identification: PR 113 Publication_Information: Publication_Place: Fairbanks, AK, USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Other_Citation_Details: 99 pp. Online_Linkage: http://dx.doi.org/10.14509/2304 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1993 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Solie and Layer, 1993 Source_Contribution: includes discussion of age results Source_Information: Source_Citation: Citation_Information: Originator: Steiger, R.H. Originator: Jager, E Publication_Date: 1977 Title: Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology Geospatial_Data_Presentation_Form: document Series_Information: Series_Name: Earth and Planetary Science Letters Issue_Identification: v.36 Other_Citation_Details: p. 359-363 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1977 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Steiger and Jager, 1977 Source_Contribution: discussion of use of decay constants in age determination Process_Step: Process_Description: Fieldwork - The Tyonek D-6 and parts of the D-5, D-7 and C-6 quadrangles were mapped in 1990 as a preliminary project in anticipation of a continued 1:63,360 mapping project in the Tyonek quadrangle. Preliminary mapping was conducted from July 20 to August 4, 1990. Members of the field crew were DGGS staff members D.N. Solie, W.G. Gilbert, E.E. Harris, J.T. Kline, S.A. Liss, M.S. Robinson and Keri DePalma. Funding did not allow the continuation of the project, and the results of the 1990 mapping were released as a preliminary geologic map (Solie and others, 1991a). Geochemical data from samples collected during the mapping project were published in 1991 (Solie and others, 1991b). At that time, the results from the 40Ar/39Ar dating were pending. A brief discussion of the results was given in Layer and Solie (1991) and Solie and Layer (1993). Preliminary mapping was conducted in 1993 in the course of 1 1/2 weeks in which mile to inch mapping of the outcrop belt of the Tingmerkpuk Sandstone was begun. In addition, measurement of a well exposed section on Tingmerkpuk Mountain, study of depositional environment of sandstones, and sampling for micropaleontology, organic geochemistry, and apatite fission track analysis was carried out. Additional mapping of the Tingmerkpuk outcrop belt and stratigraphic studies throughout the area were continued in a brief one-week field program in 1994, and in a one-month program in 1996. In these programs, reconnaissance sampling for organic geochemistry and micropaleontology, detailed stratigraphic studies of a distinctive limestone coquina and two stratigraphic sections of Upper Triassic to Hauterivian rocks, and samples for apatite fission-track cooling and uplift history were collected. Continued geologic mapping and study of Neocomian depositional environment as well as additional sampling was conducted in the final month long field season in 1998. Surficial deposits were interpreted from 1:63,360 scale aerial photographs, incorporating limited field observations made during traverses while mapping bedrock units, and by aerial reconnaissance. Published data (Chapman and Sable, 1960) served as a guide for interpretation. No glacial deposits are recognized in the Kukpowruk River area, as Quaternary glaciation apparently did not occur on the north side of the western DeLong Mountains. Bedrock mapping involved using aerial photographs and topographic maps on a daily basis for checking geologic contacts and units. Mappers recorded observations in field notebooks and on the aerial photographs and topographic maps, predominantly at 1:63,360 scale. In some areas, photocopies of topography at varying enlarged scales were used. All compilations were made by hand on stable Mylar at 1:63,360 scale. Stations were located using aerial photographs, topographic maps, compasses, and altimeters. In some instances, GPS devices with location precision varying up to 100 meters were used. Stations were also plotted by hand on stable Mylar topographic bases and coordinates determined with a digitizing tablet. Source_Used_Citation_Abbreviation: Solie and others, 1991a Source_Used_Citation_Abbreviation: Solie and others, 1991b Source_Used_Citation_Abbreviation: Layer and Solie, 1991 Source_Used_Citation_Abbreviation: Solie and Layer, 1993 Process_Date: 199007 Process_Step: Process_Description: Labwork - Separates for 40Ar/39Ar dating were prepared to >99.5 percent purity (visual inspection) using standard heavy liquid and magnetic separation techniques followed by hand-picking under a binocular microscope. Thin section examination of the samples prior to crushing indicated that the chosen minerals were free from alteration and sufficiently coarse-grained for mechanical separation. For all minerals, grains in the size range of 250 - 500 microns were used. For each sample, ~50-80 mg of biotite or 250-350 mg of hornblende or whole rock (phenocryst-free groundmass) was packaged in an aluminum foil tube and irradiated in position 5C at the McMaster University nuclear reactor, in Hamilton, Ontario. Approximately 20 samples were irradiated at a time. Six packages containing ~20 mg of the standard mineral mmhb-1 (Samson and Alexander, 1987) with an age of 513.9 Ma (Lanphere and others, 1990) were also irradiated with the samples to determine the irradiation parameter (J) and the flux gradient in the reactor. Samples and standards were analyzed 45 to 90 days after irradiation. The irradiated samples were step-heated on-line in a Modifications Ltd. low-blank furnace. Temperature control was better than 5 degrees and a maximum temperature in excess of 1600o C was achievable to ensure complete sample fusion. The extracted argon was purified in a two-stage process using a liquid nitrogen cold finger and two SAES Zr-Al getters. Prior to measurement of the Ar, the gas was collected on an activated charcoal finger. The purified Ar gas was measured using a Nuclide 6-60-SGA 15 cm mass spectrometer. The sensitivity of the spectrometer is 6.5 x 10-15 mol/mV and system noise is generally around 0.02 mV. System blanks are generally better than 1 X 10-14 mol for 40Ar. Argon isotopic measurements for both samples and standards were corrected for the system blanks, for decay of 37Ar and 39Ar, and for reactor-induced isotopic interferences. Ages were calculated using the equations and corrections from McDougall and Harrison (1999) and the constants from Steiger and Jaeger (1977). All errors on analyses are reported at the 1-sigma level. For each mass spectrometer analysis, five Ar isotope abundances are measured. 36Ar is used to determine the amount of atmospheric or initial Ar in the sample, 37Ar provides an estimation of the Ca content in the mineral, 38Ar provides an estimation of the Cl content, 39Ar reflects the K content and 40Ar is a mixture of initial and radiogenic Ar. The age of the sample is proportional to the ratio of the amount of radiogenic 40Ar to the amount of 39Ar produced by neutron bombardment from 40K. Source_Used_Citation_Abbreviation: Samson and Alexander, 1987 Source_Used_Citation_Abbreviation: Lanphere and others, 1990 Source_Used_Citation_Abbreviation: McDougall and Harrison, 1999 Source_Used_Citation_Abbreviation: Steiger and Jaeger, 1977 Process_Date: 1991 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 5 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.999600 Longitude_of_Central_Meridian: -153.000 Latitude_of_Projection_Origin: 0.0 False_Easting: 500000 False_Northing: 0 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 1 Ordinate_Resolution: 1 Planar_Distance_Units: meters Planar_Coordinate_Layer_Name: tabular data Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378206.4 Denominator_of_Flattening_Ratio: 294.978698 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: Table1_coordinates Entity_Type_Label: Table1_coordinates.csv Entity_Type_Definition: Coordinates for 40Ar/39Ar samples Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: SampleNo Attribute_Definition: Items in the Sample Number field Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Sample numbers are unique identifiers derived from the last two digits of the year the sample was collected, initials of the geologist's name who collected it, and the consecutively numbered station location. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, etc) designator as well. Attribute: Attribute_Label: Easting Attribute_Definition: UTM easting coordinate, Zone 5, NAD 27 Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 534911 Range_Domain_Maximum: 559281 Attribute_Units_of_Measure: m Attribute: Attribute_Label: Northing Attribute_Definition: UTM northing coordinate, Zone 5, NAD 27 Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 6840075 Range_Domain_Maximum: 6866077 Attribute_Units_of_Measure: m Attribute: Attribute_Label: Latitude Attribute_Definition: Latitude coordinate, NAD 27 Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 61.6924 Range_Domain_Maximum: 61.9254 Attribute_Units_of_Measure: decimal degree Attribute: Attribute_Label: Longitude Attribute_Definition: Longitude coordinate, NAD27 Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 151.8734 Range_Domain_Maximum: 152.3361 Attribute_Units_of_Measure: decimal degree Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: Table2_agesummary Entity_Type_Label: Table2_agesummary.csv Entity_Type_Definition: Summary table for 40Ar/39Ar data Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: SampleNo Attribute_Definition: Items in the Sample Number field Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Sample numbers are unique identifiers derived from the last two digits of the year the sample was collected, initials of the geologist's name who collected it, and the consecutively numbered station location. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, etc) designator as well. Attribute: Attribute_Label: Mineral Attribute_Definition: Material used for age date Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Material used for dating. Includes BI (biotite), HO (hornblende), WR (whole rock). Attribute: Attribute_Label: Integrated Age (Ma) Attribute_Definition: Integrated age in million years, Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 54.1 +/-0.5 Range_Domain_Maximum: 99.5 +/-0.7 Attribute_Units_of_Measure: Ma Attribute: Attribute_Label: Plateau or Weighted Mean Age Attribute_Definition: Summarizes the Plateau (P) Age or the Weighted Mean (W) Age in Million years for each sample Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 53.7 +/-0.4 Range_Domain_Maximum: 101.0 +/-2.0 Attribute_Units_of_Measure: Ma Attribute: Attribute_Label: Plateau Information Attribute_Definition: Summarizes number of fractions, percent 39Ar released and MSWD for each sample Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: # of fractions, % 39Ar released, MSWD for each sample Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: Table3_analyticaldata Entity_Type_Label: Table3_analyticaldata.csv Entity_Type_Definition: For each sample, the 40Ar/39Ar analytical data associated with each recorded temperature Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: SampleNo Attribute_Definition: Items in the Sample Number field Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Sample numbers are unique identifiers derived from the last two digits of the year the sample was collected, initials of the geologist's name who collected it, and the consecutively numbered station location. If more than one sample was collected from the station location, each is assigned a letter (a, b, c, etc) designator as well. Attribute: Attribute_Label: Temp Attribute_Definition: Temperature in Degrees C of step for which data were recorded Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 300 Range_Domain_Maximum: 1700 Attribute_Units_of_Measure: Degrees C Attribute: Attribute_Label: Cum. 39Ar Attribute_Definition: Cumulative 39Argon Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0000 Range_Domain_Maximum: 1.0000 Attribute: Attribute_Label: 40Ar/39Ar measured Attribute_Definition: Measured 40Ar/39Ar ratio at each heating step, corrected for blank and 39Ar decay Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 2.5705 Range_Domain_Maximum: 1134.98 Attribute: Attribute_Label: +/- Attribute_Definition: Defines the size of the error bars for each measurement to one standard deviation Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0001 Range_Domain_Maximum: 200.0000 Attribute: Attribute_Label: 37Ar/39Ar measured Attribute_Definition: The ratio of 37Ar to 39Ar measured at each temperature interval for each sample corrected for blank and 37Ar and 39Ar decay Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0001 Range_Domain_Maximum: 400.0000 Attribute: Attribute_Label: 36Ar/39Ar Attribute_Definition: Ratio of amounts of 36Ar to 39Ar measured at each temperature interval for each sample corrected for blank and 39Ar decay Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0000 Range_Domain_Maximum: 0.4000 Attribute: Attribute_Label: % Atm. 40Ar Attribute_Definition: Percent of 40Ar which is atmospheric in composition Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0 Range_Domain_Maximum: 220.0 Attribute: Attribute_Label: Ca/K Attribute_Definition: ratio of Calcium to Potassium as determined from 37Ar/39Ar Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0000 Range_Domain_Maximum: 1000.0000 Attribute: Attribute_Label: Cl/K Attribute_Definition: ratio of Chlorine to Potassium as determined from 38Ar/39Ar Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.00000 Range_Domain_Maximum: 0.80000 Attribute: Attribute_Label: 40Ar*/39ArK Attribute_Definition: ratio of radiogenic 40Ar to 39Ar derived from potassium Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -111.0000 Range_Domain_Maximum: 140.0000 Attribute: Attribute_Label: Age (Ma) Attribute_Definition: calculated age for each temperature step for each sample Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0 Range_Domain_Maximum: 150.0 Attribute_Units_of_Measure: Ma Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Contact_Position: Natural Resource Technician Contact_Address: Address_Type: mailing and physical Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5020 Contact_TDD/TTY_Telephone: None available. Contact_Facsimile_Telephone: 907-451-5050 Contact_Electronic_Mail_Address: dggspubs@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Contact_Instructions: Please view our Web site (http://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible. Resource_Description: Raw Data File 2008-4 Distribution_Liability: 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. Standard_Order_Process: Non-digital_Form: Current publication is available on paper. To purchase this or other printed reports and maps, contact DGGS by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). Payment accepted: Cash, check, money order, VISA, or MasterCard. Fees: Printed publication can be purchased for $2.00 (contact information below) plus shipping if mailed. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: PDF Format_Version_Number: 1.6 File_Decompression_Technique: No compression applied Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.14509/16521 Digital_Form: Digital_Transfer_Information: Format_Name: CSV Format_Version_Date: 2008 File_Decompression_Technique: No compression applied Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://dx.doi.org/10.14509/16521 Offline_Option: Offline_Media: CD-ROM Recording_Format: Joliet Fees: Digital files on CD-ROM are available for $10.00 (contact information below). Scanned images of these products may be viewed online or downloaded for free from the DGGS Web site. Ordering_Instructions: Order by phone (907-451-5020), e-mail (dggspubs@alaska.gov), or fax (907-451-5050). The DGGS web site (http://www.dggs.alaska.gov/) has a list of electronic data available and an order form that can be printed. Payment accepted: Cash, check, money order, VISA, or MasterCard. Technical_Prerequisites: CSV (Comma Separated Value) files can be imported and formatted with Microsoft Excel, OpenOffice.org Calc, or most spreadsheet programs and can also be viewed with most text editing programs. Metadata_Reference_Information: Metadata_Date: 20080605 Metadata_Review_Date: 20080605 Metadata_Future_Review_Date: 20100604 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager Contact_Address: Address_Type: mailing and physical address Address: 3354 College Road City: Fairbanks State_or_Province: AK Postal_Code: 99709-3707 Country: USA Contact_Voice_Telephone: 907-451-5039 Contact_Facsimile_Telephone: 907-451-5050 Contact_Electronic_Mail_Address: 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_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Access_Constraints: none Metadata_Use_Constraints: If the user has modified the data in any way they are obligated to describe the types of modifications they have performed in the supporting metadata file. User specifically agrees not to imply that changes they made were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys.