Identification_Information: Citation: Citation_Information: Originator: Layer, P.W. Originator: Benowitz, J.A. Originator: Freeman, L.K. Publication_Date: 2011 Title: 40AR/39AR Ages from the East Bonnifield geologic map area, Fairbanks A-1, Fairbanks A-2, Healy D-1, and Healy D-2 quadrangles, Alaska Geospatial_Data_Presentation_Form: tabular digital data Series_Information: Series_Name: Raw Data File Issue_Identification: RDF 2011-2 Publication_Information: Publication_Place: Fairbanks, Alaska - USA Publisher: State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys Other_Citation_Details: 22 p. Online_Linkage: http://dx.doi.org/10.14509/22482 Description: Abstract: 40Ar/39Ar data from plutonic, dike, and alteration samples collected during geologic mapping of the eastern part of the Bonnifield mining district geologic map area in parts of Fairbanks A-1 and Fairbanks A-2 and Healy D-1 and Healy D-2 quadrangles yield results indicating the plutons, dikes, and a gold-bearing quartz vein in the Bonnifield Map area range from 85 to 95 m.y. Purpose: In 2008, the Alaska Division of Geological & Geophysical Surveys (DGGS) conducted a geologic mapping project in parts of the Fairbanks A-1, Fairbanks A-2, Healy D-1, and Healy D-6quadrangles. Our purpose was to map the bedrock geology at a scale of 1:50,000 as part of the Alaska Geophysical/Geological Mineral Inventory (AGGMI) program investigations in the Bonnifield mining district. DGGS published geochemical data resulting from the 2008 work in 2009 (Freeman and others, 2009a). A brief discussion of the results was given in Freeman and others (2009b) and Freeman and others (2010). The purpose of this DGGS Raw Data File is to present the 40Ar/39Ar results and make them available for use to the public that are interested in the area. Supplemental_Information: Attribute information for the three tables (entities) is included in this metadata file under the "Entity_and_Attribution_Information" section. The tables are hierarchical with the SampleLocationDescription table being the parent of of the SummaryAges table which is in turn the parent of StepHeatingData table. The the tables are connected by the SampleNumber and DatedMaterial columns. All tables comprise a single layer as follows: >ArgonGeochronologicData: SampleLocationDescription, SummaryAges, and StepHeatingData Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 062008 Ending_Date: 072008 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -147.8028 East_Bounding_Coordinate: -147.1864 North_Bounding_Coordinate: 64.0634 South_Bounding_Coordinate: 62.9455 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 Theme_Keyword: STATEMAP Project Place: Place_Keyword_Thesaurus: None Place_Keyword: Alaska, State of Place_Keyword: Alaska Range Place_Keyword: Fairbanks Quadrangle Place_Keyword: Healy Quadrangle Place_Keyword: Denali Borough Place_Keyword: Wood River Place_Keyword: West Fork Little Delta River Place_Keyword: Dry Creek Place_Keyword: Kansas Creek Place_Keyword: Chute Creek Place_Keyword: Rogers Creek Place_Keyword: Sheep Creek Place_Keyword: Glacier Creek Place_Keyword: Threemile Creek Place_Keyword: Snow Mountain Gulch Place_Keyword: Slide Creek Place_Keyword: Glory Creek Place_Keyword: Red Mountain Creek Place_Keyword: Newman Creek Place_Keyword: Forgotten Creek Place_Keyword: Slate Creek Place_Keyword: WTF (Western Tundra Flats) prospect Place_Keyword: Red Mountain Creek prospect Place_Keyword: Dry Creek prospect Place_Keyword: LEA Creek prospect Place_Keyword: Buzby prospect Place_Keyword: Smog prospect Place_Keyword: Glory Creek prospect Place_Keyword: Kansas Creek prospect Place_Keyword: Dry Creek placer mine Place_Keyword: Newman Creek placer mine Temporal: Temporal_Keyword_Thesaurus: None Temporal_Keyword: Cretaceous Temporal_Keyword: Late Cretaceous 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. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: GIS Manager 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_Electronic_Mail_Address: dggsgis@alaska.gov Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays Data_Set_Credit: This project is part of the 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. Partial funding for the geologic mapping and 39Ar/40Ar geochronology was also provided through the State of Alaska General Fund and the U.S. Geological Survey STATEMAP Program under award number 08HQAG0051. Samples were collected as part of the geologic mapping program during 2008 by J.E. Andrew, M.B. Werdon, D.J. Szumigala, and L.K Freeman of DGGS and by R.J. Newberry of the Department of Geology & Geophysics, University of Alaska Fairbanks Native_Data_Set_Environment: Microsoft Windows XP SP2, Microsoft Excel 2003 Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Coordinates of sample locations were determined by the geologists in the field using Garmin 12XL GPS receivers with no differential correction. The coordinates were recorded in field notes along with hand sample descriptions and other locality information. The coordinates were up-loaded into an MS Access database and were checked against recorded coordinates in geologists field notes. DGGS submitted eight rock samples to the UAF Geochronology Laboratory for 40Ar/39Ar dating. 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 aluminium 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 of37Ar 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. Sample numbers in the each of the three tables were recorded by geologists in the field, recorded on sample bags and on field note sheets. The sample numbers were transcribed into an Access database by a field assistant. Table 1 was generated from the database and was cross checked against the sample numbers recorded on the bags for consistency. Sample numbers in tables 2 and 3 were generated by the UAF geochronology lab from the a list provided by DGGS and cross checked with sample numbers on the bags. We are certain that the sample numbers in the table are logically correct. Completeness_Report: This dataset includes all of the samples submitted for 40Ar/39Ar age date analyses from the Healy and Fairbanks quadrangle that were collected by DGGS during the summer of 2008. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: All field locations were determined by the geologists in the field using Garmin 12XL GPS receivers with no differential correction. Estimated position errors as calculated by the Garmin 12XL receivers were recorded in the field and range from 3 to 6 meters for the samples used in this data. Lineage: Source_Information: Source_Citation: Citation_Information: Originator: Freeman, L.K. Originator: Werdon, M.B. Originator: Szumigala, D.A. Originator: Andrew, J.A. Originator: Newberry, R.J. Originator: Athey, J.A. Publication_Date: 2009 Title: Geochemical, major-oxide, minor-oxide, trace-element and carbon data from rocks collected in 2008 in the eastern Bonnifield mining district, Fairbanks and Healy quadrangles, Alaska Geospatial_Data_Presentation_Form: tabular data Series_Information: Series_Name: Alaska Division of Geological & Geophysical Surveys Raw Data File Issue_Identification: RDF 2009-1 Other_Citation_Details: 69 p. Type_of_Source_Media: paper and digital Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2009 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Freeman and others, 2009a Source_Contribution: Provides chemical data for classification and description of samples Source_Information: Source_Citation: Citation_Information: Originator: Freeman, L.K. Originator: Newberry, R.J. Originator: Andrew, J.A. Originator: Werdon, M.B. Originator: Szumigala, D.A. Originator: Athey, J.A. Originator: Burns, L.E. Publication_Date: 2009 Title: Recent geologic mapping in the eastern Bonnifield mining district, Alaska Geospatial_Data_Presentation_Form: poster presentation Series_Information: Series_Name: Geological Society of America Abstracts with Programs Issue_Identification: v. 41, no. 7 Other_Citation_Details: (abstract), P. 282 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2009 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Freeman and others, 2009b Source_Contribution: Describes field work and initial geologic findings, reports preliminary ages Source_Information: Source_Citation: Citation_Information: Originator: Lanphere, M.A. Originator: Dalrymple, G.B. Publication_Date: 2000 Title: First-principles calibration of 38Ar tracers: Implications for the ages of 40Ar/39Ar fluence monitors Geospatial_Data_Presentation_Form: document Series_Information: Series_Name: U.S. Geological Survey Professional Paper Issue_Identification: 1621 Other_Citation_Details: 10 p. Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2000 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Lanphere and Dalrymple, 2000 Source_Contribution: Describes inter-calibration standards Source_Information: Source_Citation: Citation_Information: Originator: Samson, S.D. Originator: Alexander, E.C. Publication_Date: 1987 Title: Calibration of the inter laboratory 40Ar/39Ar dating standard, MMhb-1 Geospatial_Data_Presentation_Form: journal article 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: Inter laboratory calibration data for age determination Source_Information: Source_Citation: Citation_Information: Originator: York, D. Originator: Hall, C.M. Originator: Yanase, Y. Originator: Kenyon, W.J. Publication_Date: 1981 Title: 40Ar/39Ar dating of terrestrial minerals with a continuous laser Geospatial_Data_Presentation_Form: journal article Series_Information: Series_Name: Geophysical Research Letter Issue_Identification: v. 8 Other_Citation_Details: p. 1136-1138 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 1981 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: York, and others, 1981 Source_Contribution: Description of laser heating mass-spectrographic analysis method Source_Information: Source_Citation: Citation_Information: Originator: Layer, P.W. Originator: Hall, C.M. Originator: York, D. Publication_Date: 1987 Title: The derivation of 40Ar/39Ar age spectra of single grains of hornblende and biotite by laser step heating Geospatial_Data_Presentation_Form: journal article Series_Information: Series_Name: Geophysical Research Letter Issue_Identification: v. 14 Other_Citation_Details: p. 757-760 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: Layer and others, 1981 Source_Contribution: Description of laser step-heating mass-spectrographic analysis method Source_Information: Source_Citation: Citation_Information: Originator: Layer, P.W. Publication_Date: 2000 Title: Argon-40/argon-39 age of the El'gygytgyn impact event, Chukotka, Russia Geospatial_Data_Presentation_Form: journal article Series_Information: Series_Name: Meteoritics and Planetary Science Issue_Identification: v. 35 Other_Citation_Details: p. 591-599 Type_of_Source_Media: paper Source_Time_Period_of_Content: Time_Period_Information: Single_Date/Time: Calendar_Date: 2000 Source_Currentness_Reference: publication date Source_Citation_Abbreviation: Layer, 2000 Source_Contribution: Description of laser step-heating mass-spectrographic analysis method 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: Steiger, R.H. Originator: Jager, E. Publication_Date: 1977 Title: Sub-commission 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 eastern Bonnifield map area, including parts of the Fairbanks A-1, A-2, Healy D-1, and Healy D-2 quadrangles was mapped at 1:50,000 scale. As part of the mapping geologic, samples of igneous rocks and mineralized rocks with sericite were collected as potential samples for geochronology. Sample locations were determined using Garmin 12 XL GPS receivers. Field descriptions were recorded onto field note forms which were later transcribed into a MS Access database by a geological field assistant. Source_Used_Citation_Abbreviation: Freeman and others, 2009b Process_Date: 200807 Process_Step: Process_Description: Sample selection - A list of samples that were collected for radiometric ages was generated from the MS Access database and checked against available samples. Petrographic thin sections for the prospective samples were examined to eliminate samples that were altered. Sample locations were plotted in GIS along with the preliminary geologic map to determine which samples would provide the most geologically significant age information. Source_Used_Citation_Abbreviation: Freeman and others, 2009b Process_Date: 200812 Process_Step: Process_Description: Sample description - Sample descriptions were generated from field descriptions, petrographic descriptions, and major oxide geochemistry. The sample descriptions were also used in Freeman, and others, 2009 Source_Used_Citation_Abbreviation: Freeman and others, 2009a Process_Date: 200901 Process_Step: Process_Description: Sample preparation - Mineral separates for 40Ar/39Ar dating were prepared to greater than 99.5 percent purity (determined by visual inspection) where they were crushed, sieved, washed, and hand-picked for mineral phases or small, phenocryst-free whole-rock chips. The monitor mineral MMhb-1 (Samson and Alexander, 1987) with an age of 513.9 Ma (Lanphere and Dalrymple, 2000) was used to monitor neutron flux (and calculate the irradiation parameter, J). The samples and standards were wrapped in aluminium foil and loaded into aluminium cans 2.5 cm in diameter and 6 cm in 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. Source_Used_Citation_Abbreviation: Samson and Alexander, 1987 Source_Used_Citation_Abbreviation: Lanphere and Dalrymple, 2000 Process_Date: 200903 Process_Step: Process_Description: 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 into 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 an SAES Zr-Al getter at 400C. 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). System blanks generally were 2x10e-16 mol 40Ar and 2x10e-18mol 36Ar, which are 10 to 50 times smaller than fraction volumes. Mass discrimination was monitored by running both calibrated air shots and a zero-age glass sample. These measurements were made on a weekly to monthly basis to check for changes in mass discrimination. A summary of all the 40Ar/39Ar results is given in table 2, with all ages quoted to the +-1 sigma level and calculated using the constants of Steiger and Jaeger (1977). The integrated age is the age given by the total gas measured and is equivalent to a potassium-argon (K-Ar) age. The spectrum provides a plateau age if three or more consecutive gas fractions represent at least 50 percent of the total gas release and are within two standard deviations of each other (Mean Square Weighted Deviation less than ~2.5). All samples were run three times to verify sample consistency. Source_Used_Citation_Abbreviation: York, and others, 1981 Source_Used_Citation_Abbreviation: Layer, and others, 1987 Source_Used_Citation_Abbreviation: Layer, 2000 Source_Used_Citation_Abbreviation: McDougall and Harrison, 1999 Source_Used_Citation_Abbreviation: Steiger and Jaeger, 1977 Process_Date: 200905 Process_Step: Process_Description: Errata Corrections - Errors were found in the original text and data that were released in November 2009; this version provides corrected location coordinates for 2008JOE409 Process_Date: 2016 Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: Universal Transverse Mercator Universal_Transverse_Mercator: UTM_Zone_Number: 6 Transverse_Mercator: Scale_Factor_at_Central_Meridian: 0.9996 Longitude_of_Central_Meridian: -147 Latitude_of_Projection_Origin: 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: ArgonGeochronologicData Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1927 Ellipsoid_Name: Clarke 1866 Semi-major_Axis: 6378137 Denominator_of_Flattening_Ratio: 298.25722210088 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: ArgonGeochronologicData Entity_Type_Label: SampleLocationDescription.csv Entity_Type_Definition: Location and description of rock samples collected for trace-element geochemical analyses in the eastern Bonnifield mining district, Fairbanks and Circle quadrangles, Alaska Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: SampleNumber Attribute_Definition: Unique sample identifier Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Generic example of unique sample identifier: 20YYAAA9999X: YY=last two digits of year, AAA=geologist's initials (one to three characters), 9999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials represent the following: 'JOE' = Joe Andrew; 'LF' = Larry Freeman; 'MBW' = Melanie Werdon; 'RN' = Rainer Newberry; 'Z' = David Szumigala. Attribute: Attribute_Label: Latitude Attribute_Definition: Latitude in decimal degrees, NAD 27 Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 63.8411 Range_Domain_Maximum: 64.066 Attribute_Units_of_Measure: decimal degrees Attribute: Attribute_Label: Longitude Attribute_Definition: Longitude in decimal degrees, NAD 27 Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -147.8358 Range_Domain_Maximum: -147.3248 Attribute_Units_of_Measure: decimal degrees Attribute: Attribute_Label: UTME Attribute_Definition: Easting Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 459098 Range_Domain_Maximum: 484148 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: UTMN Attribute_Definition: Northing Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 7079208 Range_Domain_Maximum: 7104209 Attribute_Units_of_Measure: meters Attribute: Attribute_Label: Zone Attribute_Definition: UTM Zone Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: "6" indicates 06W NAD27 Alaska Projection Attribute: Attribute_Label: Description1 Attribute_Definition: Brief rock description part 1 0f 3 (truncated to 255 characters) Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Brief rock description Attribute: Attribute_Label: Description2 Attribute_Definition: Brief rock description part 2 of 3 (for descriptions longer than 255 characters) Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Brief rock description Attribute: Attribute_Label: Description3 Attribute_Definition: Brief rock description part 2 of 3 (for descriptions longer than 510 characters) Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Brief rock description Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: ArgonGeochronologicData Entity_Type_Label: SummaryAges.csv Entity_Type_Definition: Summary of 40Ar/39Ar radiometric ages of samples in this report. Preferred interpreted ages are underlined in the Adobe Acrobat portable document version of the tables. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: SampleNumber Attribute_Definition: Unique sample identifier, corresponds to "SampleNumber" attribute in "SampleLocationDescription.csv Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Generic example of unique sample identifier: 20YYAAA9999X; Where: YY=last two digits of year, AAA=geologist's initials (one to three characters), 9999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials represent the following: 'JOE' = Joe Andrew; 'LF' = Larry Freeman; 'MBW' = Melanie Werdon; 'RN' = Rainer Newberry; 'Z' = David Szumigala. Attribute: Attribute_Label: DatedMaterial Attribute_Definition: Material used for age date Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Identifies material that was used to for the age analysis includes either mineral name for mineral seperates or "Whole Rock" for samples of fine-grained or aphanitic groundmass. Some samples were run as duplicates. Attribute: Attribute_Label: IntegratedAgeMa Attribute_Definition: Integrated age and age error in million years (Ma). Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 84.3 +- 0.5 Range_Domain_Maximum: 111.1 +- 1.3 Attribute_Units_of_Measure: Ma Attribute: Attribute_Label: PlateauAgeMa Attribute_Definition: Plateau age and age error in million years (Ma) for each sample. Preferred interpreted ages are underlined in the Adobe Acrobat portable document version of the tables. Null values indicate that the age could not be determined. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 64.2 +- 1.0 Range_Domain_Maximum: 102.5 +- 1.5 Attribute_Units_of_Measure: Ma Attribute: Attribute_Label: PlateauInformation Attribute_Definition: Describes the number of fractions, percent 39Ar released, and Mean Standard Weighted Deviation (MSWD) used for the plateau age. Null values indicate that the age could not be determined. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: number of fractions, % 39Ar released, MSWD. Attribute: Attribute_Label: IsochronOrOtherInformation Attribute_Definition: Lists the isochron age and information of the isochron age if appropriate. Comments regarding some of the other age analyses are also listed in this column. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: If an isochron age is listed the column contains the age and age error in Ma, the initial ratio and error of 40Ar to 36 Ar (40Ar/36Ari), number (N) of fractions, and the Mean Standard Weighted Deviation (MSWD). Other values include "Loss Spectrum", "Reset, and "Reset/Loss". Detailed_Description: Entity_Type: Entity_Attribute_Layer_Name: ArgonGeochronologicData Entity_Type_Label: StepHeatingData.csv Entity_Type_Definition: The Step heating data is the root 40Ar/39Ar analytical data associated with each recorded Power output level for each run of dated material from a sample in this report. Entity_Type_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute: Attribute_Label: SampleNumber Attribute_Definition: Sample number contains an identifier that along with the "DatedMaterial" column relates the Step Heating data to the "SummaryAges" entity. The "SampleNumber" attribute corresponds to the "SampleNumber' attribute inboth the "SampleLocationDescription" and "SummaryAges" entities. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Generic example of unique sample identifier: 20YYAAA9999X; Where: YY=last two digits of year, AAA=geologist's initials (one to three characters), 9999=unique station number, X=unique alpha character designating a sample was taken at the field station. Geologists' initials represent the following: 'JOE' = Joe Andrew; 'LF' = Larry Freeman; 'MBW' = Melanie Werdon; 'RN' = Rainer Newberry; 'Z' = David Szumigala. Attribute: Attribute_Label: DatedMaterial Attribute_Definition: Dated Material contains a string describing the material used to for the analysis along with the "SampleNumber" attribute relates the "StepHeatingData" entity to the "SummaryAges" entity. The information in this attribute and corresponds to the "Dated Material" attributes in the "SummaryAges" entity respectively. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: Identifies material that was used to for the age analysis includes either mineral name for mineral seperates or "Whole Rock" for samples of fine-grained or aphanitic groundmass. Some samples were run as duplicates. Attribute: Attribute_Label: Laser_mW Attribute_Definition: Laser output level in megawatts, or "integrated" of each heating step Attribute_Definition_Source: University of Alaska Department of Geosciences Geochronology Laboratory Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 300 Range_Domain_Maximum: 9000 Attribute_Units_of_Measure: Megawatts Attribute_Domain_Values: Enumerated_Domain: Enumerated_Domain_Value: Integrated Enumerated_Domain_Value_Definition: Indicates row of data from entire step heating run Enumerated_Domain_Value_Definition_Source: Alaska Division of Geological & Geophysical Surveys and ALS Chemex. Attribute: Attribute_Label: Cum39Ar Attribute_Definition: Cumulative ratio of 39Argon released at this step. Null indicates that a cumulative value is not appropriate. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0022 Range_Domain_Maximum: 1.0001 Attribute: Attribute_Label: Ratio40Ar39ArMeasured Attribute_Definition: Measured 40Ar/39Ar ratio for 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: -87.3886 Range_Domain_Maximum: 887.4823 Attribute: Attribute_Label: Ratio40Ar39ArMeasuredError Attribute_Definition: The one sigma error for each 40Ar/39Ar measurement. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0332 Range_Domain_Maximum: 122.5255 Attribute: Attribute_Label: Ratio37Ar39ArMeasured Attribute_Definition: The ratio of measured 37Ar to measured 39Ar for each heating 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: -0.4268 Range_Domain_Maximum: 0.6338 Attribute: Attribute_Label: Ratio37Ar39ArMeasuredError Attribute_Definition: The one sigma error for each 37Ar/39Ar measurement. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0001 Range_Domain_Maximum: 2.7043 Attribute: Attribute_Label: Ratio36Ar39ArMeasured Attribute_Definition: Ratio of measured 36Ar to measured 39Ar for each step 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: -0.0458 Range_Domain_Maximum: 0.6338 Attribute: Attribute_Label: Ratio36Ar39ArMeasuredError Attribute_Definition: The one sigma error for each 36Ar/39Ar measurement. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0000 Range_Domain_Maximum: 0.7423 Attribute: Attribute_Label: PercentAtm40Ar Attribute_Definition: Percent of 40Ar which is atmospheric in composition at each step level Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -107.7808 Range_Domain_Maximum: 1044.4022 Attribute: Attribute_Label: RatioCaK 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: -0.0047 Range_Domain_Maximum: 20.4314 Attribute: Attribute_Label: RatioCaKError Attribute_Definition: The one sigma error for each Ca/K determination. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0001 Range_Domain_Maximum: 4.9721 Attribute: Attribute_Label: RatioClK 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: -0.0002 Range_Domain_Maximum: 0.1204 Attribute: Attribute_Label: RatioClKError Attribute_Definition: The one sigma error for each Cl/K determination. Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0000 Range_Domain_Maximum: 0.0964 Attribute: Attribute_Label: Ratio40ArRad39ArK 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: 5.592 Range_Domain_Maximum: 783.8764 Attribute: Attribute_Label: Ratio40ArRad/39ArKError Attribute_Definition: One sigma error for each 40ArRad/39ArK value Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.0403 Range_Domain_Maximum: 147.7079 Attribute: Attribute_Label: AgeMa 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: 35.9800 Range_Domain_Maximum: 2418.7300 Attribute_Units_of_Measure: Millions of years Attribute: Attribute_Label: AgeErrorMa Attribute_Definition: one sigma error of the age determination of each heating step Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: 0.2500 Range_Domain_Maximum: 841.5300 Attribute_Units_of_Measure: Millions of years Attribute: Attribute_Label: WeightedAverageOfJFromStandards Attribute_Definition: one sigma error of the age determination of each heating step Attribute_Definition_Source: Alaska Division of Geological & Geophysical Surveys Attribute_Domain_Values: Unrepresentable_Domain: J value, calculated from the weighted average of standards placed in various positions in the nuclear reactor Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys 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_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 website (http://www.dggs.alaska.gov) for the latest information on available data. 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Turnaround time is 1-2 weeks unless special arrangements are made and an express fee is paid. Shipping charge will be the actual cost of postage and will be added to the total amount due. Contact us for exact shipping amount. Metadata_Reference_Information: Metadata_Date: 20160329 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Alaska Division of Geological & Geophysical Surveys Contact_Position: Metadata Manager 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 Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998 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. 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