U-Pb and 40Ar/39Ar Geochronologic Data for Selected Rocks from the Western Alaska Range, Alaska

This dataset includes four tables with isotopic data and ages for selected igneous bedrock samples collected in 2001 through 2003 from the Western Alaska Range, southcentral Alaska: (1) the concentration of uranium (U) and thorium (Th), ratios of multiple isotopes of lead (Pb) and U, and the age of multiple analytical aliquots, or fractions, of zircon for each sample; (2) the 40Ar/39Ar analytical data and interpreted ages for each rock sample; (3) the sample location, rock characteristics, and interpreted ages for each sample; (4) a data dictionary table, provided as a reference guide for the user.

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report:

Zircon crystals were selected from sample, annealed and chemically abraded, spiked with a 233-235U205Pb tracer solution, and dissolved. Resulting solutions were dried, loaded onto Re filaments, and analyzed using a thermal ionization mass spectrometer. Analytical blanks were 0.2 pg for U and up to 1.0 pg for Pb. U fractionation was determined directly on individual runs using the 233-235U205Pb isotopic tracer. Pb isotopic ratios were corrected for fractionation of 0.30%/amu, based on replicate analyses of NBS-982 reference material. EARTHTIME U-Pb synthetic solutions were analyzed on an ongoing basis to monitor accuracy. All measured isotopic ratios are reported with associated analytical uncertainty at the 2-sigma level. Mineral and whole-rock samples for argon dating were irradiated with monitor mineral MMhb-1 with preferred age of 523.5 Ma (Renne et al., 1998). Samples and the monitors were step-heated or fused using a 6-watt argon-ion laser. Argon purification was achieved using a liquid nitrogen cold trap and SAES Zr-Al getter at 400 degrees C. The argon isotopes were measured and corrected for system blank and mass discrimination, as well as neutron induced reactions on calcium, potassium and chlorine. Typical full-system 8 min laser blank values (in moles) were generally 2e-16 mol 40Ar, 3e-18 mol 39Ar, 9e-18 mol 38Ar, and 2e-18 mol 37Ar, and 2e-18 mol 36Ar, which are 10-50 times smaller than the sample/standard volume fractions. Correction factors for nucleogenic interferences during irradiation were determined from irradiated CaF2 and K2SO4 and were: (39Ar/37Ar)Ca = 7.06e-4, (36Ar/37Ar)Ca = 2.79e-4, and (40Ar/39Ar)K = 0.0297. Mass discrimination was monitored by analyzing air shots with an assumed 40Ar/36Ar value of 295.5 (Nier, 1950). The mass discrimination during these experiments was 1.3% per mass unit. No significant variation in discrimination over the course of the analyses was measured and so a single value was used in data reduction. Ages with +/- 1 sigma error were calculated using the decay constants of Renne et al., 2010. The integrated age is the age given by the total gas measured and is equivalent to a potassium-argon (K-Ar) age. A plateau age is reported if three or more consecutive gas fractions representing at least 50 percent of the total gas released that are within two standard deviations of each other and with an overall Mean Square Weighted Deviation (MSWD) less than or equal to 2.5.

Logical_Consistency_Report:

Attribute values fall within expected ranges. Users should note that the data tables are released in Comma Separated Values format (.csv) which present the data with the correct number of significant figures; however, some software programs may alter the values and truncate trailing zeroes.

Completeness_Report: This data set is complete; no data were omitted.
Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report:

All collected samples have horizontal positions measured using hand-held GPS units with positional accuracy of 3 meters or less.

Lineage:

Source_Information:

Source_Citation:

Citation_Information:

Originator:

University of British Columbia Pacific Centre for Isotopic and Geochemical Research

Publication_Date: 2020
Title:

University of British Columbia (UBC) Pacific Centre for Isotopic and Geochemical Research (PCIGR) U-Pb zircon ID-TIMS methods

Geospatial_Data_Presentation_Form: document
Other_Citation_Details:

Supplemental Methods file included with this data package: UBC_UPb_IDTIMS_methods.pdf

Type_of_Source_Media: document
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2020

Source_Currentness_Reference: 2020

Source_Citation_Abbreviation: UPb ID-TIMS Analytical Methods
Source_Contribution:

Provides detailed descriptions of laboratory methods and data modeling for zircon U-Pb geochronology chemical abrasion thermal ionization.

Source_Information:

Source_Citation:

Citation_Information:

Originator: University of Alaska Fairbanks Geochronology Laboratory
Publication_Date: 2020
Title:

University of Alaska Fairbanks Geochronology Laboratory 40Ar / 39Ar analytical methods

Geospatial_Data_Presentation_Form: document
Publication_Information:

Publication_Place: Fairbanks, Alaska, USA
Publisher: University of Alaska Fairbanks Geochronology Laboratory

Other_Citation_Details:

Supplemental Methods file included with this data package: UAF_40Ar39Ar_methods.pdf

Type_of_Source_Media: document
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2020

Source_Currentness_Reference: 2020

Source_Citation_Abbreviation: 40Ar/39Ar Analytical Methods
Source_Contribution:

Provides detailed descriptions of laboratory methods and data modeling for whole rock argon dating geochronology.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Jaffey, A.H.
Originator: Flynn, K.F.
Originator: Glendenin, L.E.
Originator: Bentley, W.C.
Originator: Essling, A.M.
Publication_Date: 1971
Title:

Precision measurements of half-lives and specific activities of 235U and 238U

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Physical Review C
Issue_Identification: 4(5):889-906

Publication_Information:

Publication_Place: online
Publisher: American Physical Society

Other_Citation_Details:

Jaffey, A.H., Flynn, K.F., Glendenin, L.E., Bentley, W.C., and Essling, A.M. 1971. Precision measurements of half-lives and specific activities of 235U and 238U. Physical Reviews C 4(5):889-906 doi:10.1103/PhysRevC.4.1889

Online_Linkage: https://doi.org/10.1103/PhysRevC.4.1889

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1971

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Jaffey et al., 1971
Source_Contribution: Determination of precision half-life values for 235U and 238U

Source_Information:

Source_Citation:

Citation_Information:

Originator: Thirlwall, M.F.
Publication_Date: 2000
Title:

Inter-laboratory and other errors in Pb isotope analyses investigated using a 207Pb-204Pb double spike

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Chemical Geology
Issue_Identification: 163(1-4):299-322

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Thirlwall, M.E. 2000. Inter-laboratory and other errors in Pb isotope analyses investigated using a 207Pb–204Pb double spike. Chemical Geology 163(1-4):299-322 doi:10.1016/S0009-2541(99)00135-7

Online_Linkage: https://doi.org/10.1016/S0009-2541(99)00135-7

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2000

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Thirlwall, 2000
Source_Contribution: Lead isotope accuracy methods and corrections

Source_Information:

Source_Citation:

Citation_Information:

Originator: Ludwig, K.R.
Publication_Date: 2003
Title:

User's Manual for Isoplot 3.00 : A Geochronological Toolkit for Microsoft Excel

Geospatial_Data_Presentation_Form: document
Series_Information:

Series_Name: Berkeley Geochronology Center Special Publications
Issue_Identification: Special Publication no. 4

Publication_Information:

Publication_Place: online
Publisher: Berkeley Geochronology Center

Other_Citation_Details:

Ludwig, K.R. 2003. User's Manual for Isoplot 3.00 : A Geochronological Toolkit for Microsoft Excel, Berkeley Geochronology Center, Special Publication no. 4

Online_Linkage: https://www.bgc.org/isoplot

Type_of_Source_Media: document
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2003

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Ludwig, 2003
Source_Contribution: Software instructions for digital geochronological tools

Source_Information:

Source_Citation:

Citation_Information:

Originator: Schmitz, M.D.
Originator: Schoene, B.
Publication_Date: 2007
Title:

Derivation of isotope ratios, errors, and error correlations for U-Pb geochronology using 205Pb-235U-(233U)-spiked isotope dilution thermal ionization mass spectrometric data

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Geochemistry, Geophysics, Geosystems
Issue_Identification: 8(8):Q08006

Publication_Information:

Publication_Place: online
Publisher: American Geophysical Union

Other_Citation_Details:

Schmitz, M.D., and Schoene, B. 2007. Derivation of isotope ratios, errors, and error correlations for U-Pb geochronology using 205Pb-235U-(233U)-spiked isotope dilution thermal ionization mass spectrometric data. Geochemistry, Geophysics, Geosystems 8(8):Q08006 doi:10.1029/2006GC001492

Online_Linkage: https://doi.org/10.1029/2006GC001492

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2007

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Schmitz and Schoene, 2007
Source_Contribution:

Error corrections, error correlations, and isotope ratios for concordia and radiogenic model age calculations information for uranium lead isotopes.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Renne, P.R.
Originator: Swisher, C.C.
Originator: Deino, A.L.
Originator: Karner, D.B.
Originator: Owens, T.L.
Originator: DePaolo, D.J.
Publication_Date: 1998
Title:

Intercalibration of standards, absolute ages and uncertainties in 40Ar/39Ar dating

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Chemical Geology
Issue_Identification: 145(1-2):117-152

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Renne, P.R., Swisher, C.C., Deino, A.L., Karner, D.B., Owens, T.L., and DePaolo, D.J. 1998. Intercalibration of standards, absolute ages and uncertainties in 40Ar/ 39Ar dating. Chemical Geology 145(1-2):117-1522 doi:10.1016/S0009-2541(97)00159-9

Online_Linkage: https://doi.org/10.1016/S0009-2541(97)00159-9

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1998

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Renne et al., 1998
Source_Contribution:

Defines standards, absolute ages, and uncertainty information for 40Ar/39Ar geochronology.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Renne, P.R.
Originator: Mundil, R.
Originator: Balco, G.
Originator: Min, K.
Originator: Ludwig, K.R.
Publication_Date: 2010
Title:

Joint determination of 40K decay constants and 40Ar*/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Geochimica et Cosmochimica Acta
Issue_Identification: 74(18):5349-5367

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Renne, P.R., Mundil, R., Balco, G., Min, K., and Ludwig, K.R. 2010. Joint determination of 40K decay constants and 40Ar*/40K for the Fish Canyon sanidine standard, and improved accuracy for 40Ar/39Ar geochronology. Geochimica et Cosmochimica Acta 74(18):5349-5367 doi:10.1016/j.gca.2010.06.017

Online_Linkage: https://doi.org/10.1016/j.gca.2010.06.017

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2010

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Renne et al., 2010
Source_Contribution:

Provides optimized decay constants for 40Ar/40K standards and 40Ar/39Ar geochronology calculations.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Nier, A.O.
Publication_Date: 1950
Title:

A Redetermination of the Relative Abundances of the Isotopes of Carbon, Nitrogen, Oxygen, Argon, and Potassium

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Physical Review
Issue_Identification: 77(6):789-793

Publication_Information:

Publication_Place: online
Publisher: American Physical Society

Other_Citation_Details:

Nier, A.O. 1950. A Redetermination of the Relative Abundances of the Isotopes of Carbon, Nitrogen, Oxygen, Argon, and Potassium. Physical Review 77(6):789-793 doi:10.1103/PhysRev.77.789

Online_Linkage: https://doi.org/10.1103/PhysRev.77.789

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1950

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Nier, 1950
Source_Contribution: Determination of isotope abundance ratios for 36Ar/40Ar.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Jones, J.V., III
Originator: Todd, E.
Originator: Box, S.E.
Originator: Haeussler, P.J.
Originator: Holm-Denoma, C.S.
Originator: Karl, S.M.
Originator: Graham, G.E.
Originator: Bradley, D.C.
Originator: Kylander-Clark, A.R.C.
Originator: Friedman, R.M.
Originator: Layer, P.W.
Publication_Date: 2020
Title:

Cretaceous to Oligocene magmatic and tectonic evolution of the western Alaska Range: Insights from U-Pb and 40Ar/39Ar geochronology

Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Geosphere
Issue_Identification: 17(1):118-153

Publication_Information:

Publication_Place: online
Publisher: GeoScienceWorld

Other_Citation_Details:

Jones, J.V., III, Todd, E., Box, S.E., Haeussler, P.J., Holm-Denoma, C.S., Karl, S.M., Graham, G.E., Bradley, D.C., Kylander-Clark, A.R.C., Friedman, R.M., and Layer, P.W. 2020. Cretaceous to Oligocene magmatic and tectonic evolution of the western Alaska Range: Insights from U-Pb and 40Ar/39Ar geochronology. Geosphere, 2020: 17(1):118-153 doi:10.1130/GES02303.1

Online_Linkage: https://doi.org/10.1130/GES02303.1

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 2020

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Jones et al., 2020
Source_Contribution:

Detailed interpretations of these data and a discussion of the results of the study.

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: journal article
Series_Information:

Series_Name: Chemical Geology: Isotope Geoscience section
Issue_Identification: 66(1-2):27-34

Publication_Information:

Publication_Place: online
Publisher: Elsevier

Other_Citation_Details:

Samson, S.D. and Alexander, E.C. 1987. Calibration of the interlaboratory 40Ar/39Ar dating standard, MMhb-1. Chemical Geology: Isotope Geoscience section 66(1-2):27-34 doi:10.1016/0168-9622(87)90025-X

Online_Linkage: https://doi.org/10.1016/0168-9622(87)90025-X

Type_of_Source_Media: publication
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: Describes 40Ar/39Ar dating standard, MMhb-1.

Source_Information:

Source_Citation:

Citation_Information:

Originator: Renne, P.R.
Originator: Deino, A.L.
Originator: Walter, R.C.
Originator: Turrin, B.D.
Originator: Swisher, C.C., III
Originator: Becker, T.A.
Originator: Curtis, G.H.
Originator: Sharp, W.D.
Originator: Jaouni, A.R.
Publication_Date: 1994
Title: Intercalibration of astronomical and radioisotope time
Geospatial_Data_Presentation_Form: journal article
Series_Information:

Series_Name: Geology
Issue_Identification: 22(9):783-786

Publication_Information:

Publication_Place: online
Publisher: GeoScienceWorld

Other_Citation_Details:

Renne, P.R., Deino, A.L., Walter, R.C., Turrin, B.D., Swisher, C.C., III, Becker, T.A., Curtis, G.H., Sharp, W.D., and Jaouni, A.R. 1994. Intercalibration of astronomical and radioisotope time. Geology 22(9):783-786

Type_of_Source_Media: publication
Source_Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1994

Source_Currentness_Reference: publication date

Source_Citation_Abbreviation: Renne et al, 1994
Source_Contribution: Describes 40Ar/39Ar dating standard, MMhb-1.

Process_Step:

Process_Description:

Zircon grains were separated from crushed and ground samples using standard magnetic and heavy liquid techniques and hand-picked under binocular microscope. Selected grains were annealed at high temperatures, chemically abraded, spiked with a 233-235U205Pb tracer solution, and then dissolved. Resulting solutions were dried and loaded onto Re filaments. Isotopic ratios were measured by a modified single collector VG-54R or 354S thermal ionization mass spectrometer equipped with analogue Daly photomultipliers. Analytical blanks were 0.2 pg for U and up to 1.0 pg for Pb. U fractionation was determined directly on individual runs using the ET535 mixed 233-235U205Pb isotopic tracer. Pb isotopic ratios were corrected for fractionation of 0.30%/amu, based on replicate analyses of NBS-982 reference material and the values recommended by Thirlwall (2000). Data reduction used the Excel-based program of Schmitz and Schoene (2007). Standard concordia diagrams were constructed and regression intercepts and weighted averages calculated with Isoplot (Ludwig, 2003). All errors are quoted at the 2σ or 95% confidence level, unless otherwise noted. Isotopic ages were calculated with the decay constants λ238=1.55125E-10 and λ235=9.8485E-10 (Jaffey et al., 1971). Detailed analytical procedures are described in the document: "UBC_UPb_IDTIMS_methods.pdf" included in this data package.

Process_Date: 2020

Process_Step:

Process_Description:

Mineral separation was done at the Geochronology Laboratory at the University of Alaska Fairbanks (UAF). For 40Ar/39Ar analysis, bulk rock samples were crushed, sieved, washed and hand-picked to obtain pure hornblende and biotite mineral separates. In some cases, phenocryst-free groundmass (whole rock) was crushed, sieved, and washed. 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. After irradiation, the samples and standards were returned to UAF and loaded into an ultra-high vacuum extraction line. The standards were fused, and the samples heated, using a 6-watt argon-ion laser. Argon purification was achieved using a liquid nitrogen cold trap and a SAES Zr-Al getter at 400 degrees C. The argon isotopes were analyzed in a VG-3600 mass spectrometer, fitted with a single Daly detector, and operated in peak mode. Detailed analytical procedures are described in the document: "UAF_40Ar39Ar_methods.pdf" included in this data package.

Process_Date: 2020

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: UPbArAr_geochronologySampleSummary_westAKRange_jones.csv
Entity_Type_Definition:

Table with sample information, including location, rock description, and summary of geochronology analyses. The table contains 33 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample
Attribute_Definition:

Sample number as collected in the field; internal USGS identifier.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Sample identifier; most labels consisting of the last two digits of the year collected, an abbreviation identifying the collector, and a number and possible suffix. Corresponds to the 'Sample' field in all tables included with this data package.

Attribute:

Attribute_Label: AK_Region
Attribute_Definition: Part of Alaska where samples were collected
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: South-central Alaska
Enumerated_Domain_Value_Definition: Samples collected in South-central Alaska
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: AK_Subregion
Attribute_Definition: Geographic areas where samples were collected
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: South-central Alaska
Enumerated_Domain_Value_Definition: Samples collected in Western Alaska Range
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Latitude
Attribute_Definition: Latitude of sample field location in NAD83
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 61.2894
Range_Domain_Maximum: 62.0007
Attribute_Units_of_Measure: Decimal degree (NAD83)
Attribute_Measurement_Resolution: 0.0001

Attribute:

Attribute_Label: Longitude
Attribute_Definition: Longitude of sample field location in NAD83
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -152.4027
Range_Domain_Maximum: -150.5509
Attribute_Units_of_Measure: Decimal degree (NAD83)
Attribute_Measurement_Resolution: 0.0001

Attribute:

Attribute_Label: Rock_Class
Attribute_Definition: Sample rock classification
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: igneous
Enumerated_Domain_Value_Definition: rock class = igneous
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Rock_Type
Attribute_Definition: Sample rock type
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: This attribute contains general rock descriptions.

Attribute:

Attribute_Label: Rock_Comment
Attribute_Definition: Sample rock comment
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

This attribute contains additional descriptive information on rock type and/or location.

Attribute:

Attribute_Label: Analysis_Type
Attribute_Definition: Type of geochronologic analysis
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 40Ar/39Ar
Enumerated_Domain_Value_Definition:

This attribute denotes argon-argon radiometric dating procedures were performed on igneous rock.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: U-Pb ID-TIMS
Enumerated_Domain_Value_Definition:

This attribute denotes specific zircon age dating analysis procedures were performed on igneous rock.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Analysis_Lab
Attribute_Definition: Laboratory or contractor where data were collected
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: UAF
Enumerated_Domain_Value_Definition:

Laboratory located at the University of Alaska in Fairbanks, Alaska, United States of America.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: UBC
Enumerated_Domain_Value_Definition:

Laboratory located at the University of British Columbia in Vancouver, British Columbia, Canada.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: LabID
Attribute_Definition:

Sample name assigned by laboratory corresponding directly to the internal USGS identifier Sample.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Alphanumeric code consisting of an internal laboratory identifier or USGS identifier code and a hyphenated alphanumeric character sequence, with a possible suffix.

Attribute:

Attribute_Label: Sample_Material
Attribute_Definition: Mineral or rock material that was used for analysis
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: biotite
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: biotite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: hornblende
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: hornblende
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: zircon
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: zircon
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: whole rock
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: whole rock
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Preferred_Age
Attribute_Definition: Preferred age of the sample material
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.8
Range_Domain_Maximum: 122.4
Attribute_Units_of_Measure: Ma (Mega-annum or millions of years)

Attribute:

Attribute_Label: Preferred_Age_Unc_2sig
Attribute_Definition: Uncertainty (2-sigma) of the preferred age
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0
Range_Domain_Maximum: 6.0
Attribute_Units_of_Measure: Ma (Mega-annum or millions of years)

Attribute:

Attribute_Label: Preferred_Age_Type
Attribute_Definition: Type of age preferred for this sample
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 40Ar/39Ar plateau age
Enumerated_Domain_Value_Definition: Type of preferred age: 40Ar/39Ar plateau age
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 40Ar/39Ar weighted average age
Enumerated_Domain_Value_Definition: Type of preferred age: 40Ar/39Ar weighted average age
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 206Pb/235U age of oldest fraction
Enumerated_Domain_Value_Definition: Type of preferred age: 206Pb/235U age of oldest fraction
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 206Pb/235U age of youngest fraction
Enumerated_Domain_Value_Definition: Type of preferred age: 206Pb/235U age of youngest fraction
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: weighted average 206Pb/238U age
Enumerated_Domain_Value_Definition: Type of preferred age: weighted average 206Pb/238U age
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Preferred_Age_Comment
Attribute_Definition: Preferred age comment
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

General supplemental comments amplifying how Preferred_Age was calculated.

Detailed_Description:

Entity_Type:

Entity_Type_Label: UPbArAr_geochronologyDataDictionary_westAKRange_jones.csv
Entity_Type_Definition:

Table describing all fields in each of the three data tables included in this data package. Includes field names, a brief description of each field, and units of measure, as applicable. The table contains 77 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Table
Attribute_Definition: Filename of the data table the field is found in.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 40Ar39Ar_geochronologyData_westAKRange_jones.csv
Enumerated_Domain_Value_Definition: Filename of data table included in this data package.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: UPbIDTIMS_geochronologyData_westAKRange_jones.csv
Enumerated_Domain_Value_Definition: Filename of data table included in this data package.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: UPbArAr_geochronologySampleSummary_westAKRange_jones.csv
Enumerated_Domain_Value_Definition: Filename of data table included in this data package.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Field
Attribute_Definition:

Field name found in data tables included in this data package (single words or concatenated abbreviations that describe the contents of the field).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Name of each field in the CSV data tables

Attribute:

Attribute_Label: Description
Attribute_Definition: Brief description of the contents of 'Field'.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Brief description of the contents of 'Field'.

Attribute:

Attribute_Label: Units
Attribute_Definition: The unit of measurement for applicable data fields.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: n/a
Enumerated_Domain_Value_Definition: not applicable
Enumerated_Domain_Value_Definition_Source: Producer defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: %
Enumerated_Domain_Value_Definition: percent
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 10e-13 mol
Enumerated_Domain_Value_Definition: 10e-13 moles
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Ma
Enumerated_Domain_Value_Definition: Mega-annum, or millions of years
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: mg
Enumerated_Domain_Value_Definition: milligram
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Mol %
Enumerated_Domain_Value_Definition: mole percent
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: mV
Enumerated_Domain_Value_Definition: millivolt
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: mW
Enumerated_Domain_Value_Definition: milliwatt
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: pg
Enumerated_Domain_Value_Definition: picogram
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: ppm
Enumerated_Domain_Value_Definition: parts per million
Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: UPbIDTIMS_geochronologyData_westAKRange_jones.csv
Entity_Type_Definition:

Table of U-Pb zircon ID-TIMS data, reporting the isotopic concentration of uranium (U) and thorium (Th) measured in individual grains, isotopic ratios of lead and uranium, and the age of each grain calculated from the isotope ratios. The table contains 34 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample
Attribute_Definition:

Sample identifier, as assigned by the sample collector in the field; internal USGS identifier. Corresponds to 'Sample' field in all tables included in this data package.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

The value is a unique alphanumeric sequence for each sample but is repeated with an iteration suffix in this table because multiple measurement steps for each sample are analyzed, as noted in attribute Mineral_fraction_name.

Attribute:

Attribute_Label: Mineral
Attribute_Definition: Mineral analyzed
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: zircon
Enumerated_Domain_Value_Definition: Mineral analyzed = zircon
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Mineral_fraction_name
Attribute_Definition: Internal laboratory identifier of mineral fraction analyzed
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

The attributes in this data set are a concatenation of field Sample and a dash with a sequential alphanumeric suffix.

Attribute:

Attribute_Label: Mineral_fraction_weight
Attribute_Definition:

Total weight of mineral grains in fraction aliquot, in milligrams

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.004
Range_Domain_Maximum: 0.128
Attribute_Units_of_Measure: mg (milligrams)

Attribute:

Attribute_Label: U_conc_ppm
Attribute_Definition: Uranium concentration, in parts per million
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 30
Range_Domain_Maximum: 7428
Attribute_Units_of_Measure: ppm (parts per million)

Attribute:

Attribute_Label: Th_conc_ppm
Attribute_Definition: Thorium concentration, in parts per million
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.4
Range_Domain_Maximum: 91.2
Attribute_Units_of_Measure: ppm (parts per million)

Attribute:

Attribute_Label: Th_U_ratio
Attribute_Definition: Total ratio of thorium to uranium
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.048
Range_Domain_Maximum: 0.998

Attribute:

Attribute_Label: 206Pb_rad
Attribute_Definition: Radiogenic 206Pb concentration, in 10e-13 mol
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.417
Range_Domain_Maximum: 34.654
Attribute_Units_of_Measure: 10e-13 mol

Attribute:

Attribute_Label: 206Pb_rad_mol_perc
Attribute_Definition:

Mol percent 206Pb with respect to radiogenic, blank, and initial common Pb

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 72.38
Range_Domain_Maximum: 99.70
Attribute_Units_of_Measure: % (percent)

Attribute:

Attribute_Label: Pb_rad_common_ratio
Attribute_Definition:

Measured ratio of radiogenic lead to common lead corrected for spike and fractionation

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 1.0
Range_Domain_Maximum: 97.4

Attribute:

Attribute_Label: Pb_common_pg
Attribute_Definition: Common lead concentration, in picograms
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 2.12
Range_Domain_Maximum: 27.98
Attribute_Units_of_Measure: pg (picograms)

Attribute:

Attribute_Label: 206Pb_204Pb_ratio
Attribute_Definition: Total ratio of 206Pb to 204Pb
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 67.0
Range_Domain_Maximum: 6268.0

Attribute:

Attribute_Label: 208Pb_206Pb_ratio
Attribute_Definition: Total ratio of 208Pb to 206Pb
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.02
Range_Domain_Maximum: 0.32

Attribute:

Attribute_Label: 207Pb_206Pb_ratio
Attribute_Definition: Total ratio of 207Pb to 206Pb
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.05
Range_Domain_Maximum: 0.05

Attribute:

Attribute_Label: 207Pb_206Pb_ratio_unc_2sig_perc
Attribute_Definition:

Uncertainty (2-sigma) on total ratio of 207Pb to 206Pb, in percent

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.21
Range_Domain_Maximum: 21.86
Attribute_Units_of_Measure: % (percent)

Attribute:

Attribute_Label: 207Pb_235U_ratio
Attribute_Definition: Total ratio of 207Pb to 235U
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.03373
Range_Domain_Maximum: 0.08374

Attribute:

Attribute_Label: 207Pb_235U_ratio_unc_2sig_perc
Attribute_Definition:

Uncertainty (2-sigma) on total ratio of 207Pb to 206Pb, in percent

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.406
Range_Domain_Maximum: 23.339
Attribute_Units_of_Measure: % (percent)

Attribute:

Attribute_Label: 206Pb_238U_ratio
Attribute_Definition: Total ratio of 206Pb to 238U
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.00497
Range_Domain_Maximum: 0.01266

Attribute:

Attribute_Label: 206Pb_238U_ratio_unc_perc
Attribute_Definition:

Uncertainty (2-sigma) on total ratio of 207Pb to 206Pb, in percent

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.170
Range_Domain_Maximum: 2.001
Attribute_Units_of_Measure: % (percent)

Attribute:

Attribute_Label: Error_correlation
Attribute_Definition: Error correlation of the 207Pb/235U and 206Pb/238U ratios.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.448
Range_Domain_Maximum: 0.963

Attribute:

Attribute_Label: 207Pb_206Pb_age
Attribute_Definition: 207Pb/206Pb age, in millions of year before present
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 11.0
Range_Domain_Maximum: 310.0
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: 207Pb_206Pb_age_unc_2sig_abs
Attribute_Definition:

Uncertainty (2-sigma) on 207Pb/206Pb age, in millions of years before present

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 5.0
Range_Domain_Maximum: 497.0
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: 207Pb_235U_age
Attribute_Definition: 207Pb/235U age, in millions of years before present
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 33.70
Range_Domain_Maximum: 81.65
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: 207Pb_235U_age_unc_2sig_abs
Attribute_Definition:

Uncertainty (2-sigma) on 207Pb/235U age, in millions of years before present

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.24
Range_Domain_Maximum: 16.00
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: 206Pb_238U_age
Attribute_Definition: 206Pb/238U age, in millions of years before present
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 31.95
Range_Domain_Maximum: 81.09
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: 206Pb_238U_age_unc_2sig_abs
Attribute_Definition:

Uncertainty (2-sigma) on 206Pb/238U age, in millions of years before present

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.10
Range_Domain_Maximum: 1.20
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: Preferred_fraction_age
Attribute_Definition:

Preferred fraction age for calculation of sample age, selected from one of the two following fields containing calculated ages: "207Pb_206Pb_age" or "206Pb_238U_age"

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 31.95
Range_Domain_Maximum: 81.09
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: Preferred_fraction_unc_2sig_abs
Attribute_Definition: Two-sigma uncertainty on preferred grain age
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.10
Range_Domain_Maximum: 1.24
Attribute_Units_of_Measure: Ma (mega-annum or millions of years)

Attribute:

Attribute_Label: Preferred_fraction_age_type
Attribute_Definition:

Method used to calculate the values in "Preferred_fraction_age" field for each individual mineral fraction

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 206Pb_238U_age
Enumerated_Domain_Value_Definition: Method used = 206Pb_238U_age
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Interpreted_age_included
Attribute_Definition:

Indication of whether or not analysis was used in calculation of field "Preferred_age"

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Y
Enumerated_Domain_Value_Definition: Yes, analysis was used.
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: N
Enumerated_Domain_Value_Definition: No, analysis was not used.
Enumerated_Domain_Value_Definition_Source: Author defined

Detailed_Description:

Entity_Type:

Entity_Type_Label: 40Ar39Ar_geochronologyData_westAKRange_jones.csv
Entity_Type_Definition:

Table of whole rock argon detection data, reporting the isotopic concentration of argon and associated elemental components measured in sample, isotopic ratios, and the age of each sample calculated from the isotope ratios. The table contains 327 records and is presented in comma separated value (CSV) format.

Entity_Type_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample
Attribute_Definition:

Sample identifier, as assigned by the sample collector in the field; internal USGS identifier. Corresponds to 'Sample' field in all tables included in this data package.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

Sample identifier; most labels consisting of the last two digits of the year collected, an abbreviation identifying the collector, followed by a number and suffix.

Attribute:

Attribute_Label: LabID
Attribute_Definition:

Sample name assigned by laboratory corresponding directly to the internal USGS identifier Sample and mineral analyzed.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain: Alphanumeric code consisting of UAF and a hyphenated number.

Attribute:

Attribute_Label: Lab
Attribute_Definition: Laboratory in which experiment was conducted
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: UAF
Enumerated_Domain_Value_Definition: Geochronology Laboratory, University of Alaska Fairbanks
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Sample_material
Attribute_Definition: Mineral or rock material that was used for analysis.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: biotite
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: biotite
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: hornblende
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: hornblende
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: whole rock
Enumerated_Domain_Value_Definition: Mineral or rock material that was used: whole rock
Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: Monitor_mineral
Attribute_Definition: Reference mineral used to monitor neutron flux
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: MMhb-l
Enumerated_Domain_Value_Definition: hornblende standard for 40Ar/39Ar
Enumerated_Domain_Value_Definition_Source: Samson and Alexander 1987; Renne et al 1994

Attribute:

Attribute_Label: Monitor_mineral_age
Attribute_Definition: Published age of monitor mineral
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Unrepresentable_Domain:

The monitor mineral used for all analyses in this data set is MMhb-1 with age 523.5 Ma.

Attribute:

Attribute_Label: J_value
Attribute_Definition: Measure of neutron fluence
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.002456
Range_Domain_Maximum: 0.002551

Attribute:

Attribute_Label: J_unc
Attribute_Definition: Uncertainty (1-sigma) in measure of neutron fluence
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 6.72e-06
Range_Domain_Maximum: 3.64e-05

Attribute:

Attribute_Label: Laser_power_mW
Attribute_Definition:

Laser power for each heating step, in milliwatts. Blank cells indicate an integrated analysis.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 200
Range_Domain_Maximum: 9000
Attribute_Units_of_Measure: mW (milliwatts)

Attribute:

Attribute_Label: Integrated
Attribute_Definition:

Indication that values in row were calculated by weighting individual heating steps by the fraction of 39Ar released. Blank cells indicate a heating step fraction.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: Integrated
Enumerated_Domain_Value_Definition:

The term 'Integrated' indicates the values were calculated by weighting the individual heating steps by the fraction of 39Ar released.

Enumerated_Domain_Value_Definition_Source: Author defined

Attribute:

Attribute_Label: 39Ar_cum
Attribute_Definition:

Cumulative 39Ar released at this step. Blank cells indicate an integrated analysis.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.0003
Range_Domain_Maximum: 1.0
Attribute_Units_of_Measure: percentage in decimal format

Attribute:

Attribute_Label: 40Ar_mV
Attribute_Definition: Abundance of 40Ar in measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 22.42
Range_Domain_Maximum: 153999.82
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 40Ar_mV_unc
Attribute_Definition: Uncertainty (1-sigma) in 40Ar measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.14
Range_Domain_Maximum: 1101.33
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 39Ar_mV
Attribute_Definition: Abundance of 39Ar in measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.29
Range_Domain_Maximum: 7721.56
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 39Ar_mV_unc
Attribute_Definition: Uncertainty (1-sigma) in 39Ar measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.02
Range_Domain_Maximum: 36.04
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 38Ar_mV
Attribute_Definition: Abundance of 38Ar in measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.03
Range_Domain_Maximum: 1166.16
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 38Ar_mV_unc
Attribute_Definition: Uncertainty (1-sigma) in 38Ar measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.01
Range_Domain_Maximum: 6.02
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 37Ar_mV
Attribute_Definition: Abundance of 37Ar in measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.002
Range_Domain_Maximum: 15.144
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 37Ar_mV_unc
Attribute_Definition: Uncertainty (1-sigma) in 37Ar measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.022
Range_Domain_Maximum: 134.694
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 36Ar_mV
Attribute_Definition: Abundance of 36Ar in measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -1.009
Range_Domain_Maximum: 181.674
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: 36Ar_mV_unc
Attribute_Definition: Uncertainty (1-sigma) in 36Ar measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.018
Range_Domain_Maximum: 1.486
Attribute_Units_of_Measure: mV (millivolts)

Attribute:

Attribute_Label: Perc_atm_40Ar
Attribute_Definition: Percent atmospheric 40Ar in measurement
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -154.9
Range_Domain_Maximum: 120.2
Attribute_Units_of_Measure: % (percent)

Attribute:

Attribute_Label: Perc_atm_40Ar_unc
Attribute_Definition:

Uncertainty (1-sigma) in percent atmospheric 40Ar in measurement

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.1
Range_Domain_Maximum: 158.0
Attribute_Units_of_Measure: % (percent)

Attribute:

Attribute_Label: Ca_K_ratio
Attribute_Definition:

Calcium to potassium ratio as determined from 37 argon derived from calcium and 39 argon derived from potassium; 37Ar(Ca)/39Ar(K).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.027
Range_Domain_Maximum: 73.276

Attribute:

Attribute_Label: Ca_K_ratio_unc
Attribute_Definition: Uncertainty (1-sigma) in calcium to potassium ratio
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.000
Range_Domain_Maximum: 29.908

Attribute:

Attribute_Label: Cl_K_ratio
Attribute_Definition:

Chlorine to potassium ratio as determined from 38 argon derived from chlorine and 39 argon derived from potassium; 38Ar(Cl)/39Ar(K).

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -0.0068
Range_Domain_Maximum: 1.7918

Attribute:

Attribute_Label: Cl_K_ratio_unc
Attribute_Definition: Uncertainty (1-sigma) in chlorine to potassium ratio
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.00002
Range_Domain_Maximum: 2.07310

Attribute:

Attribute_Label: 40Ar_39Ar_K
Attribute_Definition: Ratio of radiogenic 40Ar to 39Ar derived from potassium
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -17.675
Range_Domain_Maximum: 4848.175

Attribute:

Attribute_Label: 40Ar_39Ar_K_unc
Attribute_Definition:

Uncertainty (1-sigma) in ratio of radiogenic 40Ar to 39Ar from potassium

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.030
Range_Domain_Maximum: 1595.774

Attribute:

Attribute_Label: Age_Ma
Attribute_Definition:

Age calculated from ratio of radiogenic 40Ar to 39Ar from potassium, in millions of years.

Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: -83.1
Range_Domain_Maximum: 4609.3
Attribute_Units_of_Measure: Ma (Mega-annum or millions of years)

Attribute:

Attribute_Label: Age_Ma_unc
Attribute_Definition: Uncertainty (1-sigma) in calculated age, in millions of years.
Attribute_Definition_Source: Author defined
Attribute_Domain_Values:

Range_Domain:

Range_Domain_Minimum: 0.1
Range_Domain_Maximum: 1304.7
Attribute_Units_of_Measure: Ma (Mega-annum or millions of years)

U-Pb and 40Ar/39Ar Geochronologic Data for Selected Rocks from the Western Alaska Range, Alaska

Metadata: