Wilson, Frederic H. (ORCID: 0000-0003-1761-6437) O'Sullivan, Paul B. (ORCID: 0000-0002-7247-5107) Pongratz, Alan L. (ORCID: 0000-0002-1174-7711) 20240830 tabular digital data Anchorage, Alaska U.S. Geological Survey, Alaska Science Center Suggested Citation: Wilson, F.H., O'Sullivan, P.B., Pongratz, A.L., 2024, U-Pb isotopic data and geochemical analyses of selected rocks from the Seldovia Quadrangle, Southcentral Alaska: U.S. Geological Survey data release, https://doi.org/10.5066/P1FDZG9X https://doi.org/10.5066/P1FDZG9X 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 isotopic ages of zircon grains aid in the interpretation of igneous intrusions and pathways following the original deposition of sedimentary rocks. The youngest zircon ages in any single sample also provide information about the maximum possible intrusion or formation age, as well as depositional age of any sedimentary rocks and, therefore, the geologic unit that contains it. Comparison of zircon age populations between samples provides a critical test of local to regional correlations of geologic units and aids in the reconstruction of geologic histories of large regions. In this study, the data were used to attempt to better understand the geologic history of the larger area of southcentral Alaska. The petrology, composition, emplacement settings, and distribution of these rocks facilitate regional correlations, help define their tectonic setting, and provide insights into their magma sources and petrogenesis. The origin and evolution of these rocks identifies some processes that can accompany subduction initiation along a continental margin. These data will be used in support of multiple geological maps, reports, and papers that describe the geological framework and mineral resource potential of these regions. Geochemical and Sr and Nd isotopic analysis of the samples of this study are used to help characterize the rocks and assist in determining their environment of eruption or emplacement. In conjunction with the geologic mapping and U-Pb isotope ages, an interpretation of this environment is suggested. Isotope ratios were measured using MC-ICP-MS (NEPTUNE Plus) internal standardization and external calibration with bracketing isotope standard reference materials. The accepted range for the JB-2 certified reference material 143Nd/144Nd measurements was 0.513069-0.513121 (the published range for this standard is 0.513062-0.513122). Accuracy was assured using JB-2 certified reference material subject to the same preparation/measurements. 2024 publication date Complete None planned -151.99 -151.74 59.45 59.20 USGS Metadata Identifier USGS:66d23a94d34ebebd6af06002 ISO 19115 Topic Category GeoScientificInformation NASA GCMD Earth Science Keyword Thesaurus Age determinations Igneous rocks Isotopic age Isotope ratios Metamorphic rocks Sedimentary rocks USGS Thesaurus Geology Geochemistry Geochronology Isotopic analysis Radiometric dating Uranium-lead analysis Uranium-thorium analysis USGS Geographic Names Information System (GNIS) Alaska English Bay Point Bede Port Graham Seldovia Kenai Prince William Sound No access constraints. No use constraints. These data are marked with a Creative Commons Zero v1.0 (CC0-1.0) Universal public domain dedication. It is requested that this USGS data release be cited for any subsequent publications that reference or utilize these data. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. U.S. Geological Survey, Alaska Science Center Mailing and Physical

4210 University Drive

Anchorage Alaska 99508 USA 907-786-7000 gs-ak_asc_datamanagers@usgs.gov Hudson, T.L. Wilson, F.H. O'Sullivan, P.B. 2024 journal article Canadian Journal of Earth Sciences 61(9):941-965 online Geological Society of Canada Hudson, T.L., Wilson, F.H., O'Sullivan, P.B., 2024. Upper Triassic igneous rocks of the southern Kenai Peninsula, Alaska—prelude to Early Jurassic subduction along the Western Wrangellia composite terrane margin. Canadian Journal of Earth Sciences 61(9):941-965. https://doi.org/10.1139/cjes-2024-0009 https://doi.org/10.1139/cjes-2024-0009 The zircon samples were run with zircon reference materials. The reference materials were analyzed until fractionation was stable and the variance in the measured 206Pb/238U and 207Pb/206Pb ratios was at or near one percent. Reference materials were subsequently analyzed together with unknowns to monitor fractionation throughout the analytical session. All measured isotopic ratios for the samples in this study are reported with associated analytical uncertainty. For geochemistry analyses, approximately 3-5 g aliquots of U.S. Geological Survey (USGS) internal standards (RPMA and RPMC) were submitted as unknown samples with each group of samples to monitor accuracy. For isotopic data, isotope ratios were measured using MC-ICP-MS (NEPTUNE Plus) internal standardization and external calibration with bracketing isotope standard reference materials. The accepted range for the JB-2 certified reference material 143Nd/144Nd measurements was 0.513069-0.513121 (the published range for this standard is 0.513062-0513122). Accuracy was assured using JB-2 certified reference material subject to the same preparation/measurements. Geochemical data reported via ALS Laboratories consisted of multiple reports over three calendar years of analysis. Approximately 3-5 g aliquots of U.S. Geological Survey (USGS) internal standards (RPMA and RPMC) were submitted as unknown samples with each group of samples to monitor accuracy. During the time interval between the earliest and latest analyses run by ALS Laboratories, Limits of Detection (LOD) were changed by the laboratory. Thus, more than one lower LOD may be shown for multiple elements, especially on samples that were reanalyzed. Results below LOD are indicated by negative values within the column of the results for that element listed in data table 'geochemistry_seldovia_wilsonOsullivan.csv'. 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. For the geochronology results, the dataset outlines specific Pb/Pb, U/Pb and Pb/Th concentrations, isotope measurements, age determinations, and correction data for the samples are listed as having an overall sample age determination in the table 'geochronologyChemistry_sampleSummary_seldovia_wilsonOsullivan.csv'. Those specific items measured are included in the results, even if the instrument measured or returned a zero result. Laboratory signal-to-noise derivation calculations, cation measurements, concordia intercept uncertainty calculations and other internal use scan data for data reduction as noted by the laboratory were not included with the results. Blank cells indicate that the instrument did not return a result or did not conduct a measurement. Horizontal position was measured using hand-held GPS units with positional accuracy of 3 meters or less. Samples were collected from the field and sent to GSS (Geosep Services) Mineral separates were obtained at the laboratories of Geosep Services in Moscow, Idaho. Zircons were separated from their host rocks using lithium metatungstate and a centrifuge; this was used in place of the conventional Wilfley table, thus guarding against loss of zircon grains that might inadvertently be washed away, undetected, in the conventional method. Zircons (both unknowns and grains of internationally accepted standard zircon [FC-1, a ~1100-Ma zircon standard]) were then mounted in 1-cm2 epoxy wafers and ground down to expose internal grain surfaces before final polishing. Grains, and the locations for laser spots on these grains, were selected for analysis from all sizes and morphologies present using transmitted light with an optical microscope at a magnification of 1500x to 2000x. This approach is used because it allows the recognition and characterization of features below the surface of individual grains, including the presence of inclusions and the orientation of cracks, which could otherwise result in spurious isotopic counts. The grains were examined using a stage- mounted cathodoluminescence imaging setup that makes it possible to detect the presence of altered zones or inherited cores within the zircon. The highest quality portions of each grain, free of alteration, inclusion, or cores, were selected for analysis. 2023 At the GeoAnalytical Laboratory, Washington State University, Pullman, Washington, U.S.A. the mounted epoxy wafer surfaces were then washed for ~10 minutes with dilute nitric acid and rinsed in ultraclean water. Analyses were carried out using a New Wave YAG 213 nm laser ablation (LA) system in line with an inductively coupled plasma, mass spectrometer (ICP-MS) at the Washington State University Geoanalytical Laboratory in Pullman, Washington, U.S.A. (e.g., Chang et al., 2006). All analyses were performed using either a 20 µm or 30 µm spot. Ablation took place within a New Wave "Supercell" ablation chamber, which was designed to achieve very high efficiency entrainment of aerosols into the carrier gas. Helium was used as the carrier gas for all experiments, and gas flow rates, together with other parameters such as torch position, were optimized before beginning a series of analyses. Each analysis consisted of a 6-second background measurement (laser off) followed by a ~24-second data acquisition period with the laser firing. A typical analytical session consisted of two analyses of the standard zircon, followed by 15 to 30 analyses of unknown zircons, two standards, 15 to 30 unknowns, and so forth, with a 20-second delay between analyses. Data were collected for the following isotopic masses: 202Hg, 204Hg, 204Pb, 206Pb, 207Pb, 208Pb, 232Th, 235U, and 238U (250 data scans over 30 s) followed by 28Si and 91Zr (5 data scans over 4 s). Methods used for sample preparation, data collection, data modeling, common Pb correction, and preferred age determination and precision are provided in the Supplementary Materials. 2023 Major and trace element analyses were completed by ALS-Global laboratories. Major elements were determined from lithium-borate fused beads that were re-ground, acid-digested, and then diluted for Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES) analysis. Loss on ignition (LOI) was determined by furnace or Thermogravimetric Analysis (TGA). All major oxide values discussed or displayed in this report with iron reported total iron (Fe2O3). Trace element determinations used fusion with lithium borate flux followed by acid dissolution and ICP-MS analysis. ALS-Global provides a quantitative method to determine trace elements from the same digested solution of a fused sample. 2023 Isotope ratio measurements were completed at the ALS Scandinavia laboratory in Lulea, Sweden. Samples were prepared by alkali fusion. Sr was separated using a Sr-resin 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-resin column (TrisKem). Recovery of both analytes was above 95%, as reported by ALS Scandinavia. Rb, Sr, Nd, and Sm concentrations were determined by ID-ICP-SKMS (Standard deviation was calculated from two independent consecutive measurements). Isotope ratios were measured using MC-ICP-MS (NEPTUNE Plus) internal standardization and external calibration with bracketing isotope standard reference materials, also as referenced or reported by ALS. 2023 LITERATURE CITED: Black, L.P., Kamo, S.L., Allen, C.M., Davis, D.W., Aleinikoff, 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, https://doi.org/10.1016/j.chemgeo.2004.01.003 Bradley, D., Haeussler, P., O'Sullivan, P., Friedman, R., Till, A., Bradley, D., Trop, J., 2009. Detrital zircon geochronology of Cretaceous and Paleogene strata across the south-central Alaskan convergent margin, in Haeussler, P.J., and Galloway, J.P., Studies by the U.S. Geological Survey in Alaska, 2007: U.S. Geological Survey Professional Paper 1760-F, https://doi.org/10.3133/pp1760F Chang, Z., Vervoort, J.D., McClelland, W.C., Knaack, C., 2006. U-Pb dating of zircon by LA-ICP-MS. Geochemistry, Geophysics, Geosystems 7(5):Q05009, https://doi.org/10.1029/2005GC001100 Chew, D.M., Donelick, R.A., 2012. Combined apatite fission track and U-Pb dating by LA-ICP-MS and its application in apatite provenance analysis. Mineralogical Association of Canada Short Course, 42:219-247 Donelick, R.A., O'Sullivan, P.B., Ketcham, R.A., 2005. Apatite fission-track analysis. Reviews in Mineralogy and Geochemistry 58(1):49-94, https://doi.org/10.2138/rmg.2005.58.3 Donelick, R.A., O'Sullivan, P.B., Donelick, M.B., 2009. A discordia-based method of zircon U-Pb dating from LA-ICP-MS analysis of single spots. In P.J. Williams et al., Smart Science for Exploration and Mining. James Cook University, Townsville, Australia, pp. 276-278 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, https://doi.org/10.1029/2007GC001805 Hults, C.P., Wilson, F.H., Donelick , R.A., O'Sullivan, P.B., 2013. Two flysch belts having distinctly different provenance suggest no stratigraphic link between the Wrangellia composite terrane and the paleo-Alaskan margin. Lithosphere 5(6):575-594, https://doi.org/10.1130/L310.1 Mattinson, J.M., 2010. Analysis of the relative decay constants of 235U and 238U by multi-step CA-TIMS measurements of closed-system natural zircon samples. Chemical Geology 275(3-4):186-198, https://doi.org/10.1016/j.chemgeo.2010.05.007 Moore, T.E., O'Sullivan, P.B., Potter, C.J., Donelick, R.A., 2015. Provenance and detrital zircon geochonologic evolution of lower Brookian foreland basin deposits of the western Brooks Range, Alaska, and implications for early Brookian tectonism. Geosphere 11(1):93-122, https://doi.org/10.1130/GES01043.1 Paces, J.B., Miller, J.D., 1993. Precise U-Pb ages of Duluth Complex and related mafic intrusions, northeastern Minnesota: Geochronological insights to physical, petrogenetic, paleomagnetic, and tectonomagmatic processes associated with the 1.1 Ga Midcontinent Rift System. Journal of Geophysical Research 98(B8):13997-14013, https://doi.org/10.1029/93JB01159 Paton, C., Woodhead, J.D., Hellstrom, J.C., Hergt, J.M., Greig, A., Maas, R., 2010. Improved laser ablation U-Pb zircon geochronology through robust downhole fractionation correction. Geochemistry, Geophysics, Geosystems 11(3), https://doi.org/10.1029/2009GC002618 Savitzky, A., Golay, M.J.E., 1964. Smoothing and differentiation of data by simplified least squares procedures. Analytical Chemistry 36(8):1627-1639, https://doi.org/10.1021/ac60214a047 Stacey, J.S., Kramers, J.D., 1975. Approximation of terrestrial lead isotope evolution by a two-stage model. Earth and Planetary Science Letters 26(2):207-221, https://doi.org/10.1016/0012-821X(75)90088-6 Steiger, R.H., Jager, E., 1977. Subcommission on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters 36(3):359-362, https://doi.org/10.1016/0012-821X(77)90060-7 Zhang, M., Ewing, R.C., Boatner, L.A., Salje, E.K.H., Weber, W.J., Daniel, P., Zhang, Y., Farhan, I., 2009, Pb* irradiation of synthetic zircon (ZrSiO4): Infrared spectroscopic study – Reply. American Mineralogist 94(5-6):856-858, https://doi.org/10.2138/am.2009.542 Unknown Point 0.0001 0.0001 Decimal degrees North American Datum of 1983 (NAD83) Geodetic Reference System of 1980 (GRS80) 6378137 298.257222101 geochronologyChemistry_dataDictionary_seldovia_wilsonOsullivan.csv Table describing all fields in the four 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 138 records and is presented in comma separated value (CSV) format. Author defined Table Filename of the data table the field is found in. Author defined geochronologyChemistry_sampleSummary_seldovia_wilsonOsullivan.csv Table with 66 records included with this data package summarizing sample collection and analyses types. Author defined geochemistry_seldovia_wilsonOsullivan.csv Table with 91 records included with this data package containing sample and analytical information, analysis dates, and the results of multiple geochemical analysis types. Author defined geochronology_U-Pb_seldovia_wilsonOsullivan.csv Table with 749 records included with this data package containing sample information, isotope ratios and concentrations, and the results of multiple types of geochronological analysis types. Author defined geochemistry_isotopeRatio_seldovia_wilsonOsullivan.csv Table with eight records included with this data package containing sample information, isotope ratios and concentrations. Author defined Field Field name found in data tables included in this data package (single words or concatenated abbreviations that describe the contents of the field). Author defined Name of each field contained in each of the CSV data tables. Description Brief description of the contents of 'Field'. Author defined Brief description of the contents of 'Field'. Units The unit of measurement for applicable data fields. Author defined n/a n/a = not applicable Author defined decimal degrees decimal degrees = an angular unit of measure used to express location Author defined Ma Ma = Mega-annum, or millions of years before present. Author defined ppm ppm = parts per million Author defined % % = percent Author defined geochronologyChemistry_sampleSummary_seldovia_wilsonOsullivan.csv Table with sample information, including location, rock description, and summary of geochronology analyses conducted. The table contains 66 records and is presented in comma separated value (CSV) format. Author defined Sample_ID Sample identifier as collected in the field; internal USGS identifier. Author defined Unique sample identifier usually consisting of the last two digits of the year collected, abbreviation identifying the collector, with a one to three-digit number and possible one to two-letter suffix. Corresponds to the 'Sample_ID' field in other tables included with this data package. Latitude Latitude given in decimal degrees datum NAD83 Author defined 59.2268 59.4447 decimal degrees 0.0001 Longitude Longitude given in decimal degrees datum NAD83 Author defined -151.9884 -151.7402 decimal degrees 0.0001 Field_Lithology Description of sampled material Author defined This free text field contains a general to detailed explanation of physical characteristics associated with the sample collected. Thin_section Indicates the number of petrographic thin sections prepared for optical analyses. Blank cells are present. Author defined x x = Indicates a thin section for the sample was produced. Author defined xx xx = Indicates two thin sections for this sample were produced. Author defined xxx xxx = Indicates three thin sections for this sample were produced. Author defined Chemistry Indicates the sample was selected for a full suite of geochemical analyses. Blank cells are present. Author defined x x = Indicates a full single suite of geochemical analyses were conducted for the sample noted. Author defined xx xx = Indicates more than one full suite of geochemical analyses were produced for the sample noted. Author defined Age_Ma Calculated age of sample based on zircon measurements, in Mega-annum (Ma), or millions of years before present. Blank cells are present. Author defined 52.5 213.6 Ma (millions of years before present) Age_Uncertainty_Ma Calculated absolute uncertainty (95% confidence) of sample age based on zircon measurements, in Mega-annum (Ma), or millions of years before present. Blank cells are present. Author defined 1.5 5.1 Ma (millions of years before present) geochemistry_seldovia_wilsonOsullivan.csv Table with whole rock geochemical analysis and laboratory standard results, including major element oxide weight percentages as well as elemental concentrations in parts per million. The table contains 91 records and is presented in comma separated value (CSV) format. Author defined Sample_ID Sample identifier per collected method; internal laboratory or USGS identifier. Author defined Sample identifier usually consisting of the last two digits of the year collected, abbreviation identifying the collector, with a one to three-digit number and possible letter suffix. Laboratory standard identifiers follow various identification conventions and are referenced in the 'Rcvd_wt_kg' field as "STD". Entries in this field that are processed samples and not laboratory standards correspond to the 'Sample_ID' field in each of the .csv files included with this data package. Analysis_Date Calendar date that the geochemical analyses were completed, in mm/dd/yyyy format. Author defined 10/16/2021 Measurements and report completed on October 16, 2021. Author defined 4/18/2022 Measurements and report completed on April 18, 2022. Author defined 1/28/2023 Measurements and report completed on January 28, 2023 Author defined 4/13/2023 Measurements and report completed on April 13, 2023 Author defined Rcvd_wt_kg Reported weight of received sample material, as recorded by the laboratory performing the analysis. Blank cells are present, indicating no sample weight was reported for reanalysis and analyses duplications. An entry of "STD" indicates a laboratory control analysis run. Author defined 0.06 1.06 kilograms (kg) SiO2_pct Silicon, as silicon oxide (SiO2) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. Author defined 0.4 92.1 weight percent (wt_%) Al2O3_pct Aluminum, as aluminum trioxide (Al2O3) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. Author defined 0.05 22.50 weight percent (wt_%) Fe2O3_pct Iron, as iron trioxide (Fe2O3) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. Author defined 0.03 51.80 weight percent (wt_%) CaO_pct Calcium, as calcium oxide (CaO) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. Author defined 0.13 31.30 weight percent (wt_%) MgO_pct Magnesium, as magnesium oxide (MgO) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. Author defined 0.05 21.60 weight percent (wt_%) Na2O_pct Sodium, as sodium oxide (Na2O) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. Author defined 0.06 9.51 weight percent (wt_%) K2O_pct Potassium, as potassium oxide (K2O) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 5.46 weight percent (wt_%) Cr2O3_pct Chromium, as chromium trioxide (Cr2O3) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.002 0.082 weight percent (wt_%) TiO2_pct Titanium, as titanium dioxide (TiO2) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 1.77 weight percent (wt_%) MnO_pct Manganese, as manganese oxide (MnO) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 2.52 weight percent (wt_%) P2O5_pct Phosphorus, as phosphorus pentoxide (P2O5) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 2.00 weight percent (wt_%) SrO_pct Strontium, as strontium dioxide (SrO) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 0.39 weight percent (wt_%) BaO_pct Barium, as barium oxide (BaO) in weight percent; measured by inductively coupled plasma atomic emission spectroscopy (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 1.58 weight percent (wt_%) LOI_pct Loss on ignition, in weight percent, at 1000 degrees C. A null or empty cell means not analyzed. Author defined 0.23 39.00 weight percent (wt_%) Total_pct Raw sum of oxide weight percent total by ICP-AES, including the LOI_pct result. A null or empty cell means not analyzed. Author defined 52.47 101.97 weight percent (wt_%) C_pct Carbon (C) concentration, in weight percent, of total carbon; determined by induction furnace/infrared spectroscopy. A null or empty cell means not analyzed. Author defined 0.01 3.21 weight percent (wt_%) S_pct Sulfur (S) concentration, in weight percent, of total sulphur; determined by induction furnace/infrared spectroscopy. A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 2.68 weight percent (wt_%) Ba_ppm Concentration of barium (Ba) in parts per million (ppm) measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A value of "10000.1111" represents the analysis is above the detection limit. Author defined 1.5 10000.1111 parts per million (ppm) Ce_ppm Concentration of cerium (Ce) in parts per million (ppm) measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 1.0 8690.0 parts per million (ppm) Cr_ppm Concentration of chromium (Cr) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Note that lower detection limit parameters for this element changed after the year 2021. Author defined -10 590 parts per million (ppm) Cs_ppm Concentration of cesium (Cs) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.02 4.19 parts per million (ppm) Dy_ppm Concentration of dysprosium (Dy) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.05 240.00 parts per million (ppm) Er_ppm Concentration of erbium (Er) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.03 88.00 parts per million (ppm) Eu_ppm Concentration of europium (Eu) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.02 151.50 parts per million (ppm) Ga_ppm Concentration of gallium (Ga) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.1 53.5 parts per million (ppm) Gd_ppm Concentration of gadolinium (Gd) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.07 359.00 parts per million (ppm) Ge_ppm Concentration of germanium (Ge) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.5 8.0 parts per million (ppm) Hf_ppm Concentration of hafnium (Hf) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.10 26.10 parts per million (ppm) Ho_ppm Concentration of holmium (Ho) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.01 38.00 parts per million (ppm) La_ppm Concentration of lanthanum (La) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.5 3600.0 parts per million (ppm) Lu_ppm Concentration of lutetium (Lu) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 6.58 parts per million (ppm) Nb_ppm Concentration of niobium (Nb) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A value of "2500.1111" represents that the analysis result is above the upper detection limit. Author defined 0.10 2500.1111 parts per million (ppm) Nd_ppm Concentration of neodymium (Nd) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.4 4380.0 parts per million (ppm) Pr_ppm Concentration of praseodymium (Pr) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A value of "1000.1111" represents that the analysis is above the upper detection limit. Author defined 0.10 1000.1111 parts per million (ppm) Rb_ppm Concentration of rubidium (Rb) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.3 227.0 parts per million (ppm) Sm_ppm Concentration of samarium (Sm) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.09 630.00 parts per million (ppm) Sn_ppm Concentration of tin (Sn) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Note that lower detection limit parameters for this element changed after the year 2021. Author defined -1.0 45.2 parts per million (ppm) Sr_ppm Concentration of strontium (Sr) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 10.3 3640.0 parts per million (ppm) Ta_ppm Concentration of tantalum (Ta) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.1 11.6 parts per million (ppm) Tb_ppm Concentration of terbium (Tb) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.01 47.10 parts per million (ppm) Th_ppm Concentration of thorium (Th) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.07 985.00 parts per million (ppm) Tm_ppm Concentration of thulium (Tm) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.01 10.80 parts per million (ppm) U_ppm Concentration of uranium (U) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.06 549.00 parts per million (ppm) V_ppm Concentration of vanadium (V) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -5 503 parts per million (ppm) W_ppm Concentration of tungsten (W) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Note that lower detection limit parameters for this element changed after the year 2021. Author defined -1.0 28.6 parts per million (ppm) Y_ppm Concentration of yttrium (Y) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. Author defined 0.2 970.0 parts per million (ppm) Yb_ppm Concentration of ytterbium (Yb) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.03 54.70 parts per million (ppm) Zr_ppm Concentration of zirconium (Zr) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -2 1175 parts per million (ppm) As_ppm Arsenic (As) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A value of "250.1111" represents that the analysis result is above the upper detection limit. Author defined 0.3 250.1111 parts per million (ppm) Bi_ppm Bismuth (Bi) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 5.59 parts per million (ppm) Hg_ppm Mercury (Hg) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.005 1.250 parts per million (ppm) In_ppm Indium (In) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.005 0.898 parts per million (ppm) Re_ppm Rhenium (Re) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.001 0.303 parts per million (ppm) Sb_ppm Antimony (Sb) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. A value of "250.1111" represents the analysis result was above the upper detection limit of the instrument. Author defined -0.05 250.1111 parts per million (ppm) Se_ppm Selenium (Se) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.2 6.4 parts per million (ppm) Te_ppm Tellurium (Te) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.01 1.35 parts per million (ppm) Tl_ppm Thallium (Tl) in parts per million (ppm); measured by inductively coupled plasma mass spectrometry (ICP-MS). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.02 1.85 parts per million (ppm) Ag_ppm Silver (Ag) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.5 68.30 parts per million (ppm) Cd_ppm Cadmium (Cd) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -0.5 20.20 parts per million (ppm) Co_ppm Cobalt (Co) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -1 763 parts per million (ppm) Cu_ppm Copper (Cu) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. Author defined 1 8310 parts per million (ppm) Li_ppm Lithium (Li) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -10 7360 parts per million (ppm) Mo_ppm Molybdenum (Mo) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -1 1085 parts per million (ppm) Ni_ppm Nickel (Ni) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -1 7700 parts per million (ppm) Pb_ppm Lead (Pb) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -2 7290 parts per million (ppm) Sc_ppm Scandium (Sc) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. A negative value represents the analysis is below the detection limit, which is the absolute value of the attribute. Author defined -1 53 parts per million (ppm) Zn_ppm Zinc (Zn) in parts per million (ppm); measured by inductively coupled plasma atomic emission spectrometry (ICP-AES). A null or empty cell means not analyzed. Author defined 5 7520 parts per million (ppm) geochronology_U-Pb_seldovia_wilsonOsullivan.csv Table with sample analysis results, including isotope concentrations and ratios, age determinations, and summary of geochronology analyses. The table contains 749 records and is presented in comma separated value (CSV) format. Author defined Sample_ID Sample identifier as collected in the field; USGS identifier. Author defined Sample identifier; most labels consist of the last two digits of the year collected, an abbreviation identifying the collector, and a number and possible suffix. Analysis_Number_ID Lab sample identification assigned by laboratory for an individual analysis procedure. Author defined An alpha-numeric code that contains the contents of field 'Sample_ID', usually followed by.a hyphen, an alphanumeric identifier, and unique analysis sequence number. U_ppm The concentration of uranium (U), in parts per million (ppm). Blank cells are present. Author defined 10.71 3937.56 parts per million (ppm) Th_ppm The concentration of thorium (Th), in parts per million (ppm). Blank cells are present. Author defined 0.92 3828.96 parts per million (ppm) UTh_Ratio The ratio of the concentration of uranium (U) to the concentration of thorium (Th). Blank cells are present, indicating the instrument did not yield a uranium or thorium concentration. Author defined 0.76 33.17 207Pb_235Uc_Ratio The ratio of lead (Pb, isotope 207) to uranium (U, isotope 235, decay corrected) for concordant scans. Author defined 0.055494 13.26997 207Pb_235Uc_Ratio_2sigma Two-sigma uncertainty for the ratio of lead (Pb, isotope 207) to uranium (U, isotope 235 decay corrected) for concordant scans. Author defined 0.005618 1.995002 206Pb_238U_Ratio The ratio of lead (Pb, isotope 206) to uranium (U, isotope 238) for concordant scans. Author defined 0.007852 0.513803 206Pb_238U_Ratio_2sigma Two-sigma uncertainty for the ratio of lead (Pb, isotope 206) to uranium (U, isotope 238) for concordant scans. Author defined 0.00031 0.056779 Error_Correlation Error correlation of 2-sigma uncertainty on 207Pb/235Uc and 206Pb/238U ratios. Author defined 0.008219 0.677845 238U_206Pb_Ratio The ratio of uranium (U, isotope 238) to lead (Pb, isotope 206) for concordant scans. Author defined 1.946271 127.3573 238U_206Pb_Ratio_2sigma Two-sigma uncertainty for the ratio of uranium (U, isotope 238) to lead (Pb, isotope 206) for concordant scans. Author defined 0.0341 14.19693 207Pb_206Pb_Ratio The ratio of lead (Pb, isotope 207) to lead (Pb, isotope 206) for concordant scans. Author defined 0.0407 0.192355 207Pb_206Pb_Ratio_2sigma Two-sigma uncertainty for the ratio of lead (Pb, isotope 207) to lead (Pb, isotope 206) for concordant scans. Author defined 0.001936 0.0851 Error_Correlation Error correlation of 2-sigma uncertainty on 238U/206Pb and 207Pb/206Pb ratios. Author defined -0.375147 0.680495 207Pb_235U_Ratio The ratio of lead (Pb, isotope 207) to uranium (U, isotope 235) for concordant scans. Author defined 0.053781 13.03894 207Pb_235U_Ratio_2sigma Two-sigma uncertainty for the ratio of lead (Pb, isotope 207) to uranium (U, isotope 235) for concordant scans. Author defined 0.005967 1.975146 208Pb_232Th_Ratio The ratio of lead (Pb, isotope 208) to thorium (Th, isotope 232) for concordant scans. Author defined 0.001769 0.182809 208Pb_232Th_Ratio_2sigma Two-sigma uncertainty for the ratio of lead (Pb, isotope 208) to thorium (Th, isotope 232) for concordant scans. Author defined 0.0002 0.0145 207Pb_235U_Age_Ma Age in Mega-annum (Ma) calculated from the ratio of 207Pb to 235U. Author defined 53.19 2682.47 Ma (millions of years before present) 207Pb_235U_Age_Ma_2sigma- Lower two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 207Pb to 235U. Author defined 5.72 290.18 Ma (millions of years before present) 207Pb_235U_Age_Ma_2sigma+ Upper two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 207Pb to 235U. Author defined 5.7 253.85 Ma (millions of years before present) 207Pb_235Uc_Age_Ma Age in Mega-annum (Ma) calculated from the ratio of 207Pb to 235Uc (decay corrected). Author defined 54.84 2699.05 Ma (millions of years before present) 207Pb_235Uc_Age_Ma_2sigma- Lower two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 207Pb to 235U (decay corrected). Author defined 5.38 275.71 Ma (millions of years before present) 207Pb_235Uc_Age_Ma_2sigma+ Upper two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 207Pb to 235U (decay corrected). Author defined 5.37 242.71 Ma (millions of years before present) 206Pb_238U_Age_Ma Age in Mega-annum (Ma) calculated from the ratio of 206Pb to 238U. Author defined 50.42 2672.85 Ma (millions of years before present) 206Pb_238U_Age_Ma_2sigma- Lower two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 206Pb to 238U. Author defined 1.98 258.41 Ma (millions of years before present) 206Pb_238U_Age_Ma_2sigma+ Upper two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 206Pb to 238U. Author defined 1.98 253.33 Ma (millions of years before present) 207Pb_206Pb_Age_Ma Age in Mega-annum (Ma) calculated from the ratio of 207Pb to 206Pb. Author defined 0.0 2762.4 Ma (millions of years before present) 207Pb_206Pb_Age_Ma_2sigma- Lower two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 207Pb to 206Pb. Author defined 0.0 1432.69 Ma (millions of years before present) 207Pb_206Pb_Age_Ma_2sigma+ Upper two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 207Pb to 206Pb. Author defined 50.58 1048.5 Ma (millions of years before present) 208Pb_232Th_Age_Ma Age in Mega-annum (Ma) calculated from the ratio of 208Pb to 232Th. Author defined 35.72 3393.46 Ma (millions of years before present) 208Pb_232Th_Age_Ma_2sigma- Lower two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 208Pb to 232Th. Author defined 4.04 269.68 Ma (millions of years before present) 208Pb_232Th_Age_Ma_2sigma+ Upper two-sigma uncertainty age in Mega-annum (Ma) calculated from the ratio of 208Pb to 232Th. Author defined 4.04 267.89 Ma (millions of years before present) Preferred_Age_Ma Preferred grain age for calculation of overall sample age (in millions of years before present, or Ma). Author defined 50.42 2762.4 Ma (millions of years before present) Preferred_Age_Ma_2sigma- Lower two-sigma uncertainty for the preferred grain age for calculation of overall sample age (in millions of years before present, or Ma). Author defined 1.98 233.87 Ma (millions of years before present) Preferred_Age_Ma_2sigma+ Upper two-sigma uncertainty for the preferred grain age for calculation of overall sample age (in millions of years before present, or Ma). Author defined 1.98 216.99 Ma (millions of years before present) Age_Type Method used to calculate the values for each individual analysis that yielded a valid result. Author defined 206Pb/238U concordant scans Indicates the measurements for lead isotope 206 to uranium isotope 238 were valid along the concordia line. Author defined 207Pb/206Pb concordant scans Indicates the measurements for lead isotope 207 to lead isotope 206 were valid along the concordia line. Author defined Concordant_Scans Number of measurements recorded for a sample that plotted along the concordia line. Author defined 2 30 geochemistry_isotopeRatio_seldovia_wilsonOsullivan.csv Table with sample information, specific isotope concentration values, and isotopic ratios. This table consists of eight records and is presented in comma separated value (CSV) format. Author defined Sample_ID Sample identifier as collected in the field; USGS identifier. Author defined Sample identifier; most labels consist of the last two digits of the year collected, an abbreviation identifying the collector, and a number and possible suffix. Lithology_Group Assigned lithologic category of the sampled material, as referenced in Hudson and others, 2024. Author defined Values in this field contain an assigned general lithologic category (Hudson and others, 2024) associated with the sample collected. Rb_ppm Isotope-dilution measured concentration of rubidium (Rb) in the sample, in parts per million (ppm). Author defined 4.56 29.8 parts per million (ppm) Sr_ppm Isotope-dilution measured concentration of strontium (Sr) in the sample, in parts per million (ppm). Author defined 48.4 505.0 parts per million (ppm) 87Sr_86Sr_ratio Ratio of strontium, isotope 87, to strontium, isotope 86, as measured in the sample. Author defined 0.70443 0.7079 87Sr_86Sr_ratio_2sigma Two-sigma uncertainty of the ratio of strontium, isotope 87, to strontium, isotope 86, as measured in the sample. Author defined 1.5e-05 4.3e-05 87Rb_86Sr_ratio Ratio of rubidium, isotope 87, to strontium, isotope 86, as measured in the sample. Author defined 0.0349 0.7684 Nd_ppm Isotope-dilution measured concentration of neodymium (Nd) in the sample, in parts per million (ppm). Author defined 4.1 26.0 parts per million (ppm) Sm_ppm Isotope-dilution measured concentration of samarium (Sm) in the sample, in parts per million (ppm). Author defined 1.3 6.06 parts per million (ppm) 143Nd_144Nd_ratio Ratio of neodymium, isotope 143, to neodymium, isotope 144, as measured in the sample. Author defined 0.512617 0.513062 143Nd_144Nd_ratio_2sigma Two-sigma uncertainty of the ratio of neodymium, isotope 143, to neodymium, isotope 144, as measured in the sample. Author defined 2.1e-05 4.9e-05 147Sm_144Nd_ratio Ratio of samarium, isotope 147, to neodymium, isotope 144, as measured in the sample. Author defined 0.1392 0.3337 GSS_Analytical_Methods.pdf Detailed documentation of sample preparation, data collection, specific laboratory methodology for geochronologic and geochemical sample processing, and data modeling. Presented in a PDF format. Author defined GSS_Supplementary_Table_S2.pdf Data file provided by GeoSep Services detailing grain measurements, uncertainty data, and supporting calculations used in age determinations. Presented in a PDF format. Author defined U.S. Geological Survey USGS ScienceBase Team Mailing and Physical

Denver Federal Center, Building 810, Mail Stop 302

Denver Colorado 80225 USA 1-888-275-8747 sciencebase@usgs.gov The U.S. Geological Survey, Alaska Science Center is the authoritative source of these data, distributed by ScienceBase (a USGS Trusted Digital Repository). Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data for other purposes or on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names is for descriptive purposes only and does not imply endorsement by the U.S. Government. CSV Tabular data in CSV format; FGDC metadata in XML and HTML formats. https://doi.org/10.5066/P1FDZG9X None 20250919 U.S. Geological Survey, Alaska Science Center Mailing and Physical

4210 University Drive

Anchorage Alaska 99508 USA 907-786-7000 gs-ak_asc_datamanagers@usgs.gov FGDC Content Standard for Digital Geospatial Metadata (CSDGM) FGDC-STD-001-1998