No unexpected values are found in these data, which were reviewed and determined to fall within normal ranges. Blank cells in the data tables indicate values were either not provided, not measured, or not calculated. Data is reported in CSV files; if these files are opened directly in Microsoft Excel, data values may be truncated if they contain trailing zeroes.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Dumoulin, J.A.
Originator: Jones, J.V. III
Originator: Bradley, D.C.
Originator: Till, A.B.
Originator: Box, S.E.
Originator: O'Sullivan, P.B.
Publication_Date: 2018
Title:
U-Pb Isotopic Data and Ages of Detrital Zircon Grains and Graptolite Fossil Data from Selected Rocks from the Western Alaska Range, Livengood area, and Seward Peninsula, Alaska - 2018
Geospatial_Data_Presentation_Form: tabular digital data
Series_Information:
Series_Name: USGS Data Release
Issue_Identification: doi:10.5066/F7PV6JKZ
Publication_Information:
Publication_Place: online
Publisher: U.S. Geological Survey, Alaska Science Center
Other_Citation_Details:
Dumoulin, J.A., Jones, J.V. III, Bradley, D.C., Till, A.B., Box, S.E., O'Sullivan, P.B., 2018, U-Pb Isotopic Data and Ages of Detrital Zircon Grains and Graptolite Fossil Data from Selected Rocks from the Western Alaska Range, Livengood area, and Seward Peninsula, Alaska - 2018: U.S. Geological Survey data release doi:/10.5066/F7PV6JKZ
Online_Linkage: https://doi.org/10.5066/F7PV6JKZ
Type_of_Source_Media: digital database file
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2018
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: Dumoulin et al., 2018
Source_Contribution:
Data were used to understand the geologic history of the Neoproterozoic through Devonian Farewell terrane of interior Alaska and to illuminate its early sedimentary history and possible geologic connections with other Alaska terranes.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Black, L.P.
Originator: Kamo, S.L.
Originator: Allen, C.M.
Originator: Davis, D.W.
Originator: Aleinkoff, J.N.
Originator: Valley, J.W.
Originator: Mundil, R.
Originator: Campbell, I.H.
Originator: Korsch, R.J.
Originator: Williams, I.S.
Originator: Foudoulis, C.
Publication_Date: 2004
Title:
Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID–TIMS, ELA–ICP–MS and oxygen isotope documentation for a series of zircon standards
Geospatial_Data_Presentation_Form: journal article
Series_Information:
Series_Name: Chemical Geology
Issue_Identification: 205(1-2):115-140
Publication_Information:
Publication_Place: online
Publisher: Elsevier
Other_Citation_Details:
Black, L.P., Kamo, S.L., Allen, C.M., Davis, D.W., Aleinkoff, J.N., Valley, J.W., Mundil, R., Campbell, I.H., Korsch, R.J., Williams, I.S., Foudoulis, C., 2004, Improved 206Pb/238U microprobe geochronology by the monitoring of a trace-element-related matrix effect; SHRIMP, ID–TIMS, ELA–ICP–MS and oxygen isotope documentation for a series of zircon standards, Chemical Geology 205(1-2):115-140 doi:10.1016/j.chemgeo.2004.01.003
Online_Linkage: https://doi.org/10.1016/j.chemgeo.2004.01.003
Type_of_Source_Media: publication
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2004
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: Black et al., 2004
Source_Contribution:
Precise isotope dilution–thermal ionization mass spectrometry (ID–TIMS) documentation is given for two new Paleozoic zircon standards (TEMORA 2 and R33). This approach has the potential to reduce age biases associated with different techniques, different instrumentation and different standards within and between laboratories.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Gehrels, G.E.
Originator: Valencia, V.A.
Originator: Ruiz, J.
Publication_Date: 2008
Title:
Enhanced precision, accuracy, efficiency, and spatial resolution of U-Pb ages by laser ablation–multicollector–inductively coupled plasma–mass spectrometry
Geospatial_Data_Presentation_Form: journal article
Series_Information:
Series_Name: Geochemistry, Geophysics, Geosystems
Issue_Identification: 9(3):Q03017
Publication_Information:
Publication_Place: online
Publisher: Wiley
Other_Citation_Details:
Gehrels, G.E., Valencia, V.A., Ruiz, J., 2008, Enhanced precision, accuracy, efficiency, and spatial resolution of U-Pb ages by laser ablation–multicollector–inductively coupled plasma–mass spectrometry, Geochemistry, Geophysics, Geosystems 9(3):Q03017 doi:10.1029/2007GC001805
Online_Linkage: https://doi.org/10.1029/2007GC001805
Type_of_Source_Media: publication
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2008
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: Gehrels et al., 2008
Source_Contribution:
New developments in instrumentation and experimental methodology, as described herein and by other researchers, now make it possible it to correct for common Pb accurately (using measured 204Pb), to acquire geochronologic information rapidly (30–40 unknowns/h), to generate U-Pb ages with an accuracy of better than 1% for most zircon standards.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Pullen, A.
Originator: Ibanez-Mejia, M.
Originator: Gehrels, G.E.
Originator: Giesler, D.
Originator: Pecha, M.
Publication_Date: 2018
Title:
Optimization of a Laser Ablation-Single Collector-Inductively Coupled Plasma-Mass Spectrometer (Thermo Element 2) for accurate, precise, and efficient Zircon U-Th-Pb geochronology
Geospatial_Data_Presentation_Form: journal article
Series_Information:
Series_Name: Geochemistry, Geophysics, Geosystems
Issue_Identification: 19(10):3689-3705
Publication_Information:
Publication_Place: online
Publisher: Wiley
Other_Citation_Details:
Pullen, A., Ibanez-Mejia, M., Gehrels, G.E., Giesler, D., Pecha, M., 2018, Optimization of a Laser Ablation-Single Collector-Inductively Coupled Plasma-Mass Spectrometer (Thermo Element 2) for accurate, precise, and efficient Zircon U-Th-Pb geochronology, Geochemistry, Geophysics, Geosystems 19(10):3689-3705 doi:10.1029/2018GC007889
Online_Linkage: https://doi.org/10.1029/2018GC007889
Type_of_Source_Media: publication
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2018
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: Pullen et al., 2018
Source_Contribution:
Describe methodologies for optimization of laser ablation-single collector-inductively coupled plasma-mass spectrometer for the accurate determination of initial-Pb-corrected (using measured 204Pb) U-Th-Pb zircon ages, taking full advantage of the high sensitivity provided by the Thermo Element 2 ICP-MS instruments fitted with a high-performance low ultimate vacuum Jet interface.
Source_Information:
Source_Citation:
Citation_Information:
Originator: Gehrels, G.E.
Publication_Date: 20120130
Title:
Detrital Zircon U-Pb Geochronology: Current Methods and New Opportunities
Geospatial_Data_Presentation_Form: publication
Publication_Information:
Publication_Place: online
Publisher: Wiley Online Library
Other_Citation_Details:
Online_Linkage: https://doi.org/10.1002/9781444347166.ch2
Type_of_Source_Media: Digital and/or Hardcopy
Source_Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date: 2012
Source_Currentness_Reference: publication date
Source_Citation_Abbreviation: Gehrels, 2012
Source_Contribution:
Outlines improvements in methods of precision of detrital zircon age determinations, newer information tools and age determination abilities, and availability of age determination information from sedimentary sequences.
Process_Step:
Process_Description:
Detrital zircons were separated from bulk sample using lithium polytungstate and a centrifuge. Zircon grains were mounted in epoxy wafers and then ground down to expose the grain interior, and then polished. Isotopic analyses were performed with either a new Wave UP-213 or New Wave YAG 213 laser ablation system in line with Finnigan Element2 magnetic sector, inductively coupled plasma, mass spectrometer (ICP-MS) at Washington State University Geoanalytical Laboratory in Pullman, Washington. For more on analytical procedures, see Dumoulin et al. (2018).
Process_Date: 2012
Process_Step:
Process_Description:
Detrital zircons were separated from bulk sample using lithium polytungstate and a centrifuge. Zircon grains were mounted in epoxy wafers and then ground down to expose the grain interior, and then polished. Isotopic analyses were performed with either a new Wave UP-213 or New Wave YAG 213 laser ablation system in line with Finnigan Element2 magnetic sector, inductively coupled plasma, mass spectrometer (ICP-MS) at Washington State University Geoanalytical Laboratory in Pullman, Washington. For more on analytical procedures, see Dumoulin et al. (2018).
Process_Date: 2021
Process_Step:
Process_Description:
Zircons were separated by hand crushing with steel mortar and pestle. Crushed material was sieved at 0.25 mm, and the >0.25mm residue was crushed and sieved again. This process was repeated until approximately 90% of the rock volume was less than 0.25 mm. A Gemini table was used to perform density-based separation on the <0.25 mm crushed fraction of the rock. The heavy fractions were then rinsed with deionized water, soaked for 24 hours in 3% acetic acid, rinsed again with deionized water, soaked for 24 hours in hydrogen peroxide, rinsed a third time with deionized water, and dried at 40 °C. Dried fractions were run through a Frantz magnetic separator to remove magnetic minerals, and a final density separation was performed using the heavy liquid methylene iodide.
Process_Date: 2011
Process_Step:
Process_Description:
Zircon grains were prepared for U-Th-Pb geochronology by arranging zircon age standard (Sri Lanka, primary, Gehrels et al., 2008; R33, secondary, Black et al., 2004) and dump-mounting unknown grains into 1 cm × 0.25 cm rows, mounting the rows in epoxy, and polishing off approximately 25–50 μm of the mount to expose the interiors of the zircon crystals. After polishing, the mounts were carbon coated and imaged at the Stanford U.S. Geological Survey (USGS) Micro Analysis Center using secondary electron and cathode luminescence detectors on a JEOL LV5600 scanning electron microscope equipped with a Hamamatsu photomultiplier tube. The images were used to positively identify zircon from other mineral species that were present on the mount and to guide the placement of ablation pits into portions of grains devoid of cracks and non-zircon inclusions.
Process_Date: 2011
Process_Step:
Process_Description:
Detrital zircon U-Th-Pb geochronology analyses were performed at the Arizona LaserChron Center at the University of Arizona via laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS) during October 2011, using the methodology of Gehrels (2012). Sample introduction was performed by ablation of 30 μm diameter pits in zircon using a New Wave 213 excimer laser. Ablated material was transported by helium carrier gas into the plasma source of a Nu Plasma high-resolution ICP-MS, from which a positively charged ion beam was extracted and manipulated to measure the intensities of atomic masses of interest in multicollector mode. For each sample, 25–35 Sri Lanka primary age standards, 3–5 R33 secondary age standards, and 100 unknowns were analyzed in a sequence that bracketed the start and end of each sample with 4–5 primary standards, interspersed a primary standard after every five unknowns, and included one secondary standard after every 25–35 unknowns.
Process_Date: 2011
Process_Step:
Process_Description:
Zircons were disaggregated in a jaw crusher and disc grinder to fine sand size. The fraction finer than 60 mesh sieve (<250 microns) was washed in a 1 litre beaker and the clay-sized fraction was poured out. Dried sample was put in a Frantz to 1.5A and the non-magnetic material was soaked in 10% acetic acid to remove carbonates and 3% H2O2 to remove remaining clays. Dried sample was put in sodium polytungstate (2.85 g/cm3) and then methylene iodide (3.3 g/cm3). If pyrite was present, sample was soaked in 15% nitric acid for 30 minutes on a hot plate to dissolve sulfides. Samples were then prepared and analyzed on a single-collector laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) at the Arizona LaserChron Center at the University of Arizona following the methods described in Pullen et al. (2018).
Process_Date: 2016