U-Pb Isotope Geochronology Data and Geochemical Analyses of Selected Rocks from the Seldovia Quadrangle, Southcentral Alaska
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This dataset contains U-Pb isotopic data and associated ages of zircons within the lithologic framework of igneous, metaigneous, and metasedimentary rocks collected from the Seldovia quadrangle in southcentral Alaska. The samples were collected as part of geological mapping and research conducted from 2020 to 2023 and funded by the Mineral Resources Program of the U.S. Geological Survey. Zircon grains were separated and analyzed by GeoSep Services (GSS). All analyses were conducted between 2021 and 2023 using laser-ablation-inductively-coupled-plasma-mass spectrometry (LA-ICP-MS) techniques. Also described in this report are the major and trace element geochemical analyses for samples collected as part of the mapping project. Analyses were conducted by ALS Global. Major elements were determined from fused bead, acid digestion, and ICP-AES analysis. Loss on ignition (LOI) was determined by furnace or TGA. Also included are rubidium (Rb), strontium (Sr), samarium (Sm), and neodymium (Nd) analyses conducted by the ALS Scandinavia laboratory in Lulea, Sweden. Samples were prepared by alkali fusion. Sr was separated using Sr-specific column (TrisKem). Nd was separated from matrix first as sum of REE using a AG50-x8 column (AlfaAesar) and then from Sm on a Ln column (TrisKem).
U-Pb and 40Ar/39Ar Geochronologic Data for Selected Rocks from the Western Alaska Range, Alaska
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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.
U-Pb and 40Ar/39Ar Geochronologic Data for Selected Rocks from the Western Alaska Range, Alaska
공공데이터포털
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.
New U-Pb Geochronology and Geochemistry of Paleozoic Metaigneous Rocks from Western Yukon and Eastern Alaska
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This data release contains three tables of U-Pb zircon isotopic data generated from analyses of 40 metaplutonic and metavolcanic rocks from the Yukon-Tanana Upland of western Yukon and east-central Alaska and one sample from southern Yukon. One of the tables also reports U-Pb data for two titanite analyses for one of the samples. U-Pb zircon ages from analyzed samples range from 363.5 ± 3.8 to 253.1 ± 0.7 Ma and were collected from parautochthonous North America and the allochthonous Yukon-Tanana terrane. U-Pb zircon data include 216 individual analyses by ID-TIMS and 35 individual analyses of two samples by LA-ICP-MS. ID-TIMS analyses of titanite give concordant 206Pb-238U ages of 333 and 338 Ma. Two U-Pb tables report the isotopic composition of uranium (U) and thorium (Pb) measured in each grain, ratios of isotopes of lead and uranium isotopes, and the age of each grain. A third table reports interpreted U-Pb ages, sample locations, tectonic assemblage or unit, lithology, analysis method, laboratory used, and basis for age assignment. The data release also contains two tables of whole-rock major- and trace-element geochemical data for metaigneous rocks from the Yukon-Tanana Upland in east-central Alaska for augen gneiss (15 samples) and amphibolite (30 samples).
New U-Pb Geochronology and Geochemistry of Paleozoic Metaigneous Rocks from Western Yukon and Eastern Alaska
공공데이터포털
This data release contains three tables of U-Pb zircon isotopic data generated from analyses of 40 metaplutonic and metavolcanic rocks from the Yukon-Tanana Upland of western Yukon and east-central Alaska and one sample from southern Yukon. One of the tables also reports U-Pb data for two titanite analyses for one of the samples. U-Pb zircon ages from analyzed samples range from 363.5 ± 3.8 to 253.1 ± 0.7 Ma and were collected from parautochthonous North America and the allochthonous Yukon-Tanana terrane. U-Pb zircon data include 216 individual analyses by ID-TIMS and 35 individual analyses of two samples by LA-ICP-MS. ID-TIMS analyses of titanite give concordant 206Pb-238U ages of 333 and 338 Ma. Two U-Pb tables report the isotopic composition of uranium (U) and thorium (Pb) measured in each grain, ratios of isotopes of lead and uranium isotopes, and the age of each grain. A third table reports interpreted U-Pb ages, sample locations, tectonic assemblage or unit, lithology, analysis method, laboratory used, and basis for age assignment. The data release also contains two tables of whole-rock major- and trace-element geochemical data for metaigneous rocks from the Yukon-Tanana Upland in east-central Alaska for augen gneiss (15 samples) and amphibolite (30 samples).
New U-Pb Geochronology and Geochemistry of Paleozoic Metaigneous Rocks from Western Yukon and Eastern Alaska
공공데이터포털
This data release contains three tables of U-Pb zircon isotopic data generated from analyses of 40 metaplutonic and metavolcanic rocks from the Yukon-Tanana Upland of western Yukon and east-central Alaska and one sample from southern Yukon. One of the tables also reports U-Pb data for two titanite analyses for one of the samples. U-Pb zircon ages from analyzed samples range from 363.5 ± 3.8 to 253.1 ± 0.7 Ma and were collected from parautochthonous North America and the allochthonous Yukon-Tanana terrane. U-Pb zircon data include 216 individual analyses by ID-TIMS and 35 individual analyses of two samples by LA-ICP-MS. ID-TIMS analyses of titanite give concordant 206Pb-238U ages of 333 and 338 Ma. Two U-Pb tables report the isotopic composition of uranium (U) and thorium (Pb) measured in each grain, ratios of isotopes of lead and uranium isotopes, and the age of each grain. A third table reports interpreted U-Pb ages, sample locations, tectonic assemblage or unit, lithology, analysis method, laboratory used, and basis for age assignment. The data release also contains two tables of whole-rock major- and trace-element geochemical data for metaigneous rocks from the Yukon-Tanana Upland in east-central Alaska for augen gneiss (15 samples) and amphibolite (30 samples).
Data for Uranium-Lead Geochronology, Carbon and Sulfur Stable Isotopes, and Raman Spectroscopy from Graphite Creek, Alaska
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The data release includes zircon and titanite U-Pb-Thisotope and age data, monazite U-Pb-Th isotope, trace element and age data, carbon and sulfur stableisotope data, and graphite Raman spectroscopy data, from samples collected at the Graphite Creek deposit, Alaska. Sample location information and descriptions are in table "_sampleDescriptions_". Table "_ramanPeakFits_" contains all raw Raman spectra peak fit data. Table "_monaziteIsotopic_" contains all monazite data. Table "_carbonSulfurIsotopic_" contains all carbon and sulfur data. Folder "_zirconData_" contains all zircon numerical data, plots, and images. Raw numerical data are presented in tabular format; plots of select zircon data (conventional discordia, U/Th vs age, U (ppm) vs age, and percent discordance vs age) are presented in PDF format; scanning electron microscope cathodoluminescence images of zircon are presented in TIF format.
Data for Uranium-Lead Geochronology, Carbon and Sulfur Stable Isotopes, and Raman Spectroscopy from Graphite Creek, Alaska
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This data release supports the paper titled, "Insights into the metamorphic history and origin of flake graphite mineralization at the Graphite Creek graphite deposit, Seward Peninsula, Alaska, USA", published in the journal Mineralium Deposita. The data release includes zircon and titanite U-Pb-Thisotope and age data, monazite U-Pb-Th isotope, trace element and age data, carbon and sulfur stableisotope data, and graphite Raman spectroscopy data, from samples collected at the Graphite Creek deposit, Alaska. Sample location information and descriptions are in table "sample_descriptions.csv". The raw numerical data are presented in tabular format. Additionally, plots of select zircon data – conventional discordia, U/Th vs age, U (ppm) vs age, and percent discordance vs age – are included in PDF format (zircon_plots.pdf), along with scanning electron microscope cathodoluminescence images of zircon in TIFF format. Folder "zircon_data" contains all zircon numerical data, plots, and images. Table "raman_peak_fits.csv" contains all raw Raman spectra peak fit data. Table "monazite_isotopic_data.csv" contains all monazite data. Table "carbon_sulfur_isotopic_data.csv" contains all carbon and sulfur data. Interpretations of the data are presented in the aforementioned journal paper.
U-Pb Zircon Data for Igneous and Metaigneous Rocks of Interior and Southwest Alaska
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This dataset contains U-Pb isotopic data and associated dates for sampled igneous, meta-igneous, and metamorphic rocks of interior and southwestern Alaska. Samples were collected during geologic mapping and mineral deposit research from 2019 to 2023. Mapping and research were funded by the Mineral Resources Program of the U.S. Geological Survey. Mineral separations were conducted at the U.S. Geological Survey mineral separation laboratory in Denver, Colorado and GeoSep Services in Moscow, Idaho. Laser-ablation-inductively-coupled-plasma-mass spectrometry analyses of zircon grains were performed from 2020 through 2024 at the U.S Geological Survey Microbeam Laboratory in Denver, Colorado and at the GeoAnalytical Laboratory, Washington State University, Pullman, Washington by GeoSep Services.
U-Pb Isotopic Data and Ages of Detrital Zircon Grains, Whole Rock Major and Trace-element Geochemistry, and Whole Rock Isotopic Data from Selected Rocks from the Western Alaska Range, Medfra area, and Livengood area, Alaska
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This data release contains 3 datasets, U-Pb isotopic data and associated ages of detrital zircon grains for 27 sedimentary rocks, whole rock major and trace-element geochemistry for 15 igneous or phosphatic rock samples, and whole rock Sr, Nd, and Pb isotopic data for 6 igneous rock samples. The samples were collected from multiple localities across Alaska as part of geological mapping and research conducted between 1974 and 2014 and funded by the Mineral Resources Program of the U.S. Geological Survey.