Todd, Erin (ORCID: 0000-0002-4871-9730) Kylander-Clark, Andrew R.C. (ORCID: 0000-0002-4034-644x) 20230202 tabular digital data Anchorage, Alaska U.S. Geological Survey, Alaska Science Center Suggested Citation: Todd, E., Kylander-Clark, A.C., 2023, U-Pb ages, hafnium isotope ratios, and trace element concentrations by Laser-Ablation Split Stream (LASS) analysis of igneous zircons from the western Alaska Range: U.S. Geological Survey data release, https://doi.org/10.5066/P9HE4U9N https://doi.org/10.5066/P9HE4U9N This dataset contains U-Pb isotopic data and ages, Hf isotope data, and trace element concentrations of zircon from igneous rocks collected from the western Alaska Range of south-central Alaska. The sample suite was collected as part of geological mapping and supporting geochemical and geochronological analysis conducted from 2011 to 2013. We also analyzed portions of remainders of previously collected igneous bedrock samples from the USGS archive, allowing expansion of the dataset to include igneous bodies that were not sampled during 2011–2013 field work or were outside the area of focused project field work. Zircon was obtained from these igneous rocks to determine the crystallization age for the bedrock samples. The data tables accompanying this data release report the isotopic composition of uranium (U) and thorium (Th) measured in each grain, ratios of three isotopes of lead (208Pb, 207Pb, and 206Pb), two isotopes of uranium (235U and 238U), one isotope of thorium (232Th), and the age of each grain, plus trace element abundances from the same ablated aliquot, including P, V, Sr, high field strength elements (HFSE), and rare earth elements (REE). Reported Hf (and Lu) isotope data includes 176Hf/177Hf, 176Lu/177Hf, and 178Hf/177Hf ratios, calculated epsilon Hf values, and age-corrected isotope ratios and epsilon values. U-Pb zircon dates and compositions from igneous rocks aid in the interpretation of the age of original formation (e.g. crystallization age) and sources of igneous rocks with variety of compositions. These data will be used in support of multiple geological maps, reports, and papers that describe the geological framework and mineral resource potential of the region. Sample collection was funded by the Mineral Resources Program of the U.S. Geological Survey. Bulk rock samples were processed into concentrated mineral separates in USGS laboratories in Denver, Colorado, or by Apatite to Zircon, Inc. (A2Z) and analyzed at the laser-ablation split-stream (LASS) laboratory at the University of California, Santa Barbara. The LASS configuration splits the laser-ablated aerosol stream between a quadrupole inductively coupled plasma spectrometer (Q-ICPMS) and a multi-collector inductively coupled plasma spectrometer (MC-ICP-MS), enabling simultaneous measurements of ages, trace elements, and Hf isotopes on the same volume of ablated material. U-Th-Pb isotopes and trace element concentrations were analyzed by Q-ICPMS, while Hf isotopes were analyzed by MC-ICP-MS. 2023 publication date Complete None planned -154.47 -150.62 62.80 60.86 USGS Metadata Identifier USGS:ASC514 ISO 19115 Topic Category GeoScientificInformation NASA GCMD Earth Science Keyword Thesaurus Earth science Igneous rocks USGS Thesaurus Geology Geochronology Geochemistry Isotopic analysis Uranium-lead analysis Radiometric dating None U-Pb geochronology Lu/Hf U/Pb U/Th/Pb Zircon Laser-Ablation Split-Stream LASS Laser-Ablation Multi Collector Inductively Coupled Plasma Mass Spectrometry LA-MC-ICPMS Trace elements USGS Geographic Names Information System (GNIS) Alaska Alaska Range No access constraints. No use constraints. These data are marked with a Creative Common CC0 1.0 Universal License and are in the public domain. 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 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. Layer, P.W. 2021 journal article Geosphere 17(1):118-153 online The Geological Society of America 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., Layer, P.W., 2021. Cretaceous to Oligocene magmatic and tectonic evolution of the western Alaska Range: insights from U-Pb and 40Ar/39Ar geochronology. Geosphere 17(1):118–153. https://doi.org/10.1130/GES02303.1 https://doi.org/10.1130/GES02303.1 Each run in each analytical session began with a round-robin of multiple analyses of zircon reference materials (RM), including 91500, GJ1, Plesovice, Mud Tank, and Temora2 to constrain stable isotope fractionation and measured 206Pb/238U and 207Pb/206Pb ratios was at or near 1 percent. The same zircon RM were interleaved among samples, with one analysis of 91500 plus a rotation of the other four RM run after every eighth sample spot. All measured isotopic ratios are reported with associated analytical uncertainty. Hf isotope ratios measured on these standard reference materials agree within error to accepted values. Trace element data are calibrated with analysis of matrix-matched reference materials (91500 and GJ1) interleaved among samples. No unexpected values are found in these data. Blank cells in the data tables indicate values were either not provided, not measured, or not calculated. The geochronological data provided in this data release may contain trailing zeros. If the CSV files are opened directly in Microsoft Excel, data values may be truncated. This dataset contains LASS procedural analysis on samples selected from within a geographically bounded area of interest in the western portion of the Alaska Range. The dataset includes instances of failed analyses of specific grains due to instrumentation error. All samples collected after the calendar year 2000 have horizontal positions measured using hand-held GPS units with positional accuracy of approximately 3 meters. Different collectors used different datums – NAD83 and WGS84, so datum for each sample location is noted in the table. The location for samples collected prior to the year 2000 have been obtained from 1:63,360 scale topographic field sheets or field notebooks and converted from Datum NAD27 to NAD83. Zircon grains were separated from crushed and ground samples using standard magnetic and heavy liquid techniques, hand-picked under binocular microscope, and mounted in epoxy discs. The mounts were ground to expose the grain interior, further polished, and imaged using a digital camera mounted to a binocular picking microscope to identify any inclusions or other features such as cracks to be avoided during analysis. Detailed analytical procedures are described in the accompanying document included in this data package: "Supplemental_Info_Analytical_Methods_UCSB_LASS.pdf". Unknown LITERATURE CITED: Blichert-Toft, J., Albarede, F., 1997. The Lu-Hf isotope geochemistry of chondrites and the evolution of the mantle-crust system. Earth and Planetary Science Letters 148(1-2):243-258. https://doi.org/10.1016/S0012-821X(97)00040-X Ferry, J.M., Watson, E.B., 2007. New thermodynamic models and revised calibrations for the Ti-in-zircon and Zr-in-rutile thermometers. Contributions to Mineralogy and Petrology 154(4):429-437. https://doi.org/10.1007/s00410-007-0201-0 Griffin, W.L., Pearson, N.J., Belousova, E.A., Jackson, S.E., van Achterbergh, E., O'Reilly, S.Y., Shee, S.R., 2000. The Hf isotope composition of cratonic mantle: LAM-MC-ICPMS analysis of zircon megacrysts in kimberlites. Geochimica et Cosmochimica Acta 64(1):133-147. https://doi.org/10.1016/S0016-7037(99)00343-9 Scherer, E., Munker, C., Mezger, K., 2001. Calibration of the lutetium-hafnium clock. Science 293(5530):683-687. https://doi.org/10.1126/science.1061372 Unknown Point 0.0001 0.0001 Decimal degrees North American Datum of 1983 (NAD83) and World Geodetic System 1984 (WGS84) Geodetic Reference System 1980 (GRS80) and WGS84 6378137 298.257223563 geochronology_LASS_dataDictionary_wAlaskaRng_2023_todd.csv Table describing all fields in each table included in this data package. Includes field names, a brief description of each field, and the data units, if applicable. This table contains 140 records and is presented in comma separated value (.csv) format. Author defined TABLE Filename of the CSV data table included in this data package. Author defined geochronology_LASS_zircon_wAlaskaRng_2023_todd Filename of CSV data table Author defined geochronology_LASS_sampleSummary_wAlaskaRng_2023_todd Filename of CSV data table Author defined FIELD_NAME Name of each field as they appear in the CSV data tables (single words or concatenated abbreviations that describe the contents of the field). Author defined Name of each field in the CSV data tables FIELD_EXPLANATION Brief description of the contents of each field in the CSV data tables Author defined Attributes in this field are brief descriptions of the contents of each field and include unit of measure, as applicable. UNITS The unit of measurement for applicable data fields. Author defined n/a not applicable Author defined cps counts per second Author defined decimal degrees unit of angular measure Author defined degrees C degrees Celsius Author defined Ga Giga-annum, or billions of years before present Author defined Ma Mega-annum, or millions of years before present Author defined ppm parts per million Author defined um micrometers Author defined geochronology_LASS_sampleSummary_wAlaskaRng_2023_todd.csv Table with sample information, including location, rock descriptions, hafnium isotope data, median trace element concentrations, and geochronology analysis summary data. This table contains 109 records and is presented in comma separated value (.csv) format. Author defined Index Numeric identifier used for sorting purposes within this table only. Author defined 1 109 Sample Sample number as collected in the field; USGS identifier. Author defined 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. Sample identifiers link to field Sample in table "geochronology_LASS_zircon_wAlaskaRng_2023_todd.csv". LONGITUDE Sample location longitude in decimal degrees. Author defined -154.4630 -150.6214 Decimal degrees 0.0001 LATITUDE Sample location latitude in decimal degrees. Author defined 61.0029 62.7936 Decimal degrees 0.0001 DATUM Geodetic model used for sample location; NAD83 or WGS1984. Author defined NAD83 North American Datum of 1983; semi-major axis = 6378137.0 and flattening ratio denominator = 298.257222101 Author defined WGS84 World Geodetic System 1984; semi-major axis = 6378137.0 m and flattening ratio = 298.257223563 Author defined SERIES Magmatic series assumed for sample; geochronological groupings based on discussion in Jones et al. (2021) and expanded on by Todd et al. (in prep.). Author defined TR Rock associated with Triassic magmatism Author defined ELC Rock associated with early Late-Cretaceous magmatism Author defined MLC Rock associated with middle Late-Cretaceous magmatism Author defined LC Rock associated with Late-Cretaceous magmatism Author defined E Rock associated with Eocene magmatism Author defined EO Rock associated with Oligocene magmatism Author defined P Rock associated with Paleocene magmatism Author defined ROCK_CLASS Rock type (Igneous, metamorphic, or sedimentary). Author defined Igneous Primary rock classification = Igneous Author defined ROCK_NAME Rock name, as described in original collector field notes. Author defined Sample rock nomenclature. ROCK_COMMENT A more detailed rock description. Author defined This free text field contains a more descriptive rock description than 'ROCK_NAME'. UPb_Age_Interpretation Interpretation whether an analyzed grain represents the main crystallization stage of the host rock, or "inheritance" (xenocrystic) from a different source. Author defined Crystallization age Analyzed grain represents the main crystallization stage of the host rock. Author defined Mount Internal laboratory alphanumeric identifier for a specific sample mount. Author defined Values in this field consist of three letter initials followed by a two-digit number, denoting a specific and repeatable laboratory equipment configuration. Session_Run Year and month of analytical session, and Run sequence within that session, when analysis was conducted. Author defined Values in this data set are a concatenation of the calendar year followed by a "/", the number associated with the calendar month, a two-digit number indicating the procedural sequence during the month indicated, the word "_RUN_", and a two-digit number. Multiple runs are indicated in certain cells. Spot_Size_um Laser spot size during analyses, in micrometers (um). Author defined Values in this field are concatenated numeric spot analysis sizes from the instrument in micrometers and the suffix 'um". Some samples were run more than once with more than one spot size, as indicated. Laser_Run_Conditions Laser run conditions during analysis; repetition rate (Hz), fluence (%) and Output (mJ). Author defined The attributes in this field are a concatenation of the frequency of the laser in Hz (cycles per second), power setting of the laser in % (percent), and output power setting of the laser in mJ (milliJoules). Additional comments are included if multiple settings or analytical sessions were used. Comment_age Comments on sample age or analytical observations. Author defined The values in this dataset include specific additional or amplifying remarks regarding the type of analysis or procedures. This is a free text field. Comment_chem Comments on sample trace elements or hafnium isotope observations. Blank cells may be present, indicating that no additional chemistry observations were made as a result of the procedures completed. Author defined The values in this data set include general observations regarding procedural results. This is a free text field. Spots_total Total number of zircon measurements made for a sample population. Author defined 1 56 Method Analytical configuration used; "LASS," short for laser-ablation split-stream, indicates simultaneous quadrupole inductively coupled plasma spectrometer (Q-ICPMS) and multi-collector inductively coupled plasma spectrometer (LA-MC-ICP-MS) analyses, measuring U-Th-Pb and trace elements on Q-ICPMS and Hf isotopes on MC-ICP-MS. "LA-ICP-MS" indicates Hf isotopes on MC-ICP-MS only. For samples with LA-MC-ICP-MS Hf isotope analyses only, ages and TE concentrations shown are measured by SHRIMP ["LA-MC-ICPMS (+SHRIMP)"], from published sources detailed in Supplement. Author defined LASS Laser-ablation split-stream analytical configuration was used. Author defined LASS & LA-MC-ICPMS Both laser-ablation split-stream and laser-ablation multi collector inductively coupled plasma mass spectrometry analytical configurations were used. Author defined LA-MC-ICPMS (+SHRIMP) Both laser-ablation multi collector inductively coupled plasma mass spectrometry and sensitive high-resolution ion microprobe analytical configurations were used. Author defined LASS & LA-MC-ICPMS (+SHRIMP) A combination of laser-ablation split-stream, laser-ablation multi collector inductively coupled plasma mass spectrometry, and sensitive high-resolution ion microprobe analytical configurations were used. Author defined UPb_MEAS_USED Number of zircon measurements per sample, out of the permissible measurements (i.e., total analyzed minus excluded), contributing to calculation of weighted means of U-Pb ages. "SHRIMP" indicates age shown is the published weighted mean age, from sources detailed in Supplement. Author defined Attributes for this data set are 'SHRIMP', 'single grain', and a series of results in the format 'X of Y', where 'X' indicates number of measurements used and 'Y' indicates the number of measurements permitted. Hf_MEAS_USED Number of zircon measurements per sample, out of the permissible measurements (i.e., total analyzed minus excluded), contributing to calculation of weighted means of Hafnium isotopes Author defined Attributes for this data set are 'single grain' and a series of results in the format 'X of Y', where 'X' indicates number of measurements used and 'Y' indicates the number of measurements permitted. TE_MEAS_USED Number of zircon measurements per sample, out of the permissible measurements (i.e., total analyzed minus excluded), contributing to calculation of medians of trace element compositions. "SHRIMP" indicates compositions shown are the median of published values, from sources detailed in Supplement. Author defined Attributes for this data set are 'SHRIMP', 'single grain', and a series of results in the format 'X of Y', where 'X' indicates number of measurements used and 'Y' indicates the number of measurements permitted. Age_Type Method used to calculate the values for each individual analysis that yielded a valid result. "age7corr" indicates a 207Pb-corrected 206Pb/238U age (Ma), for U-Pb ages < 1.4Ga; "SHRIMP" indicates 207Pb/206Pb age (Ma) for U-Pb ages >1.4Ga. Author defined The only values for this data set are 'SHRIMP' and 'age7corr'. w_mean_age_Ma Weighted mean of 207Pb-corrected 206Pb/238U ages (Ma) Author defined 26.7 441.4 Mega-annum, or millions of years before present w_mean_age_Ma_2sigma 2-sigma (uncertainty) in the weighted mean of 207Pb-corrected 206Pb/238U ages (Ma). Long-term instrument reproducibility is typically higher than analytical uncertainty, approximately 2% of the age. Author defined 0.2 55.2 Mega-annum, or millions of years before present MSWD Mean square weighted deviation of ages; blank cells are present to indicate either single grains or published SHRIMP ages. Author defined 0.14 7.94 176Hf_177Hf_ratio The ratio of 176Hf to 177Hf. Author defined 0.282623 0.283110 176Hf_177Hf_ratio_2sigma 2-sigma (uncertainty) values for the ratio of 176Hf to 177Hf. Author defined 0.000010 0.000130 176Lu_177Hf_ratio The weighted mean ratio of 176Lu to 177Hf. Author defined 0.000252 0.006616 176Lu_177Hf_ratio_2sigma 2-sigma (uncertainty) values for the weighted mean ratio of 176Lu to 177Hf Author defined 0.000001 0.001279 eHf Epsilon Hf value, assuming a chondritic 176Hf/177Hf value of 0.282772 (Blichert-Toft and Albarede, 1997). Author defined -5.27 11.95 eHf_2sigma 2-sigma (uncertainty) values for epsilon Hf value, assuming a chondritic 176Hf/177Hf value of 0.282772 (Blichert-Toft and Albarede, 1997). Author defined 0.35 4.60 176Hf_177Hf_T Age-corrected 176Hf/177Hf ratio, assuming Lutetium-176 decay constant of 1.86x10e-11 (Scherer et al., 2001). Author defined 0.282614 0.283108 eHf_T Age-corrected epsilon Hf value assuming chondritic 176Hf/177Hf ratio of 0.282772 and 176Lu/177Hf ratio of 0.0332 (Blichert-Toft and Albarede, 1997). Author defined -3.86 13.64 T_DM_Hf Model age in billions of years before present (Ga) assuming a present-day depleted mantle 176Lu/177Hf and 176Hf/177Hf of 0.0384 and 0.28325 (Griffin et al., 2000). Author defined 0.20 0.93 (Ga) Giga-annum, or billions of years before present m_Zr_ppm Median zirconium (Zr) concentration, in parts per million (ppm). Blank cells are present. Author defined 3.80E+05 4.87E+05 ppm (parts per million) m_Si_ppm Median silica (Si) concentration, in parts per million (ppm). Blank cells are present. Author defined 1.37E+05 1.99E+05 ppm (parts per million) m_P_ppm Median phosphorous (P) concentration, in parts per million (ppm). Blank cells are present. Author defined 77.6 737.5 ppm (parts per million) m_Ti_ppm Median titanium (Ti) concentration, in parts per million (ppm). Author defined 1.39 36.18 ppm (parts per million) m_V_ppm Median vanadium (V) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.96 0.96 ppm (parts per million) m_Sr_ppm Median strontium (Sr) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.26 0.26 ppm (parts per million) m_Y_ppm Median yttrium (Y) concentration, in parts per million (ppm). Author defined 329 8100 ppm (parts per million) m_Nb_ppm Median niobium (Nb) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.38 121.50 ppm (parts per million) m_La_ppm Median lanthanum (La) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.001 7.700 ppm (parts per million) m_Ce_ppm Median cerium (Ce) concentration, in parts per million (ppm). Author defined 1.4 81.0 ppm (parts per million) m_Pr_ppm Median praseodymium (Pr) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.04 2.24 ppm (parts per million) m_Nd_ppm Median neodymium (Nd) concentration, in parts per million (ppm). Author defined 0.1 13.6 ppm (parts per million) m_Sm_ppm Median samarium (Sm) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.4 19.6 ppm (parts per million) m_Eu_ppm Median europium (Eu) concentration, in parts per million (ppm). Author defined 0.04 4.88 ppm (parts per million) m_Gd_ppm Median gadolinium (Gd) concentration, in parts per million (ppm). Author defined 5.0 164.4 ppm (parts per million) m_Tb_ppm Median terbium (Tb) concentration, in parts per million (ppm). Blank cells are present. Author defined 2.6 65.5 ppm (parts per million) m_Dy_ppm Median dysprosium (Dy) concentration, in parts per million (ppm). Author defined 29.2 844.0 ppm (parts per million) m_Ho_ppm Median holmium (Ho) concentration, in parts per million (ppm). Blank cells are present. Author defined 12.9 298.7 ppm (parts per million) m_Er_ppm Median erbium (Er) concentration, in parts per million (ppm). Author defined 63 1500 ppm (parts per million) m_Tm_ppm Median thulium (Tm) concentration, in parts per million (ppm). Blank cells are present. Author defined 16.9 265.3 ppm (parts per million) m_Yb_ppm Median ytterbium (Yb) concentration, in parts per million (ppm). Author defined 137 2620 ppm (parts per million) m_Lu_ppm Median lutetium (Lu) concentration, in parts per million (ppm). Blank cells are present. Author defined 33.2 9253.3 ppm (parts per million) m_Hf_ppm Median hafnium (Hf) concentration, in parts per million (ppm). Author defined 5663 15068 ppm (parts per million) m_Ta_ppm Median tantalum (Ta) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.407 60.600 ppm (parts per million) m_Pb_ppm Median lead (Pb) concentration, in parts per million (ppm). Blank cells are present. Author defined 5.6 81.4 ppm (parts per million) m_Th_ppm Median thorium (Th) concentration, in parts per million (ppm). Author defined 26.7 3680 ppm (parts per million) m_U_ppm Median uranium (U) concentration, in parts per million (ppm). Author defined 59 12100 ppm (parts per million) T_C Ti-in-zircon thermometer (degrees C), after Ferry and Watson (2007), calculated using median Ti concentrations and assuming SiO2 and TiO2 of 0.7 Author defined 614 929 degrees Celsius geochronology_LASS_zircon_wAlaskaRng_2023_todd.csv Table with zircon LASS data, reporting the isotropic concentration of uranium (U) and thorium (Th) measured in individual grains, isotopic ratios of lead and uranium, and the age of each grain interpreted from the isotopic ratios. This table also reports hafnium isotope and concentrations of selected trace elements measured in the same grains. This table contains 2,391 records and is presented in comma separated value (.csv) format. Author defined Index Numeric identifier used for sorting purposes within this table only. Author defined 1 3041 Sample Sample number as collected in the field; USGS identifier. Author defined 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 'Sample' field in table "geochronology_LASS_sampleSummary_wAlaskaRng_2023_todd.csv" included with this data package. Mount Internal laboratory alphanumeric identifier for a specific sample mount. Author defined Values in this field consist of three letter initials followed by a two-digit number, denoting a specific and repeatable laboratory equipment configuration. Session_Run Year and month of analytical session, and Run sequence within that session, when analysis was conducted. Author defined Values in this data set are a concatenation of the calendar year followed by a "/", the number associated with the calendar month, a two-digit number indicating the procedural sequence during the month indicated, the word "_RUN_", and a two-digit number. Multiple runs are indicated in certain cells. Timestamp Concatenation of date and time of analysis for individual analysis spot. Author defined 2014-08-11/ 13:20:41 2022-09-23/ 15:22:56 Date Time (YYYY-MM-DD/ hh:mm:ss) local time Spot_ID Internal ID number of individual analysis location, generally the sample name or other laboratory identifier followed by a number for each individual grain. Author defined The values in this data set are a concatenation of parts of the field 'Sample' or other laboratory identifier, a dash or underscore, and a number indicating a unique location during the procedure. Spot_Size_um Laser spot size during analyses, in micrometers (um). Author defined 40 65 (um) micrometers Laser_Run_Conditions Laser run conditions during analysis; repetition rate (Hz), fluence (%) and output (mJ). Author defined The attributes in this field are a concatenation of the frequency of the laser in Hz (cycles per second), power setting of the laser in % (percent), and output power setting of the laser in mJ (milliJoules). Method Analytical configuration used; "LASS" short for laser-ablation split-stream, indicates simultaneous quadrupole inductively coupled plasma spectrometer (Q-ICPMS) and multi-collector inductively coupled plasma spectrometer (MC-ICP-MS) analyses, measuring U-Th-Pb and trace elements on Q-ICPMS and Hf isotopes on MC-ICP-MS. "LA-ICP-MS" indicates Hf isotopes on MC-ICP-MS only. Author defined LASS Laser-ablation split-stream analytical configuration Author defined LA-ICP-MS Laser-ablation inductively coupled plasma spectrometer analytical configuration Author defined LA-MC-ICPMS (+SHRIMP) Both laser-ablation multi collector inductively coupled plasma mass spectrometry and sensitive high-resolution ion microprobe analytical configurations were used. Author defined U_Pb_x_from_wtmn Grains with discordant ages (generally <0.80 or >1.05 concordance; tolerances adjusted to <0.70 and >1.10 for smallest sample populations), calculated analytical age uncertainty in excess of 5%, or U/Th ratios indicating metamorphic origin, or grains interpreted as inherited, that are omitted from calculated weighted mean ages. Blank cells are present. Author defined Blank cells Grain was not omitted from calculation. Author defined X Value indicates a grain was omitted from calculations. Author defined Hf_x_from_wtmn Grains omitted from calculation of Hf isotope characterization for zircon populations. These include all grains excluded from calculated weighted mean ages, plus those with uncertainty in excess of 5%, or obvious outliers, the latter of which are typically associated with particularly small grain to spot size ratios. Blank cells are present. Author defined Blank cells Grain was not omitted from calculation. Author defined X Value indicates a grain was omitted from calculations. Author defined TE_x_from_median Grains omitted from calculation of median trace element composition for zircon populations. These include all grains excluded from weighted mean and Hf isotopes, and zircon grains suspected of containing inclusions imparting non-zircon signal on integration of measured trace elements. Blank cells are present. Author defined Blank cells Grain was not omitted from calculation. Author defined X Value indicates a grain was omitted from calculations. Author defined Comment_exclude Shorthand description for why a grain was considered not permissible for deriving representative values for any one of the three datasets (U/Pb age, Hf isotope, trace elements); for more details see the document: "Supplemental_Info_Analytical_Methods_UCSB_LASS.pdf", included in this data package. "eHf" refers to calculated epsilon Hf value. Blank cells are present. Author defined The values in this data set are general remarks denoting rationale for exclusion. U_ppm The concentration of uranium (U), in parts per million (ppm). Blank cells are present. Author defined 22 71000 ppm (parts per million) Th_ppm The concentration of thorium (Th), in parts per million (ppm). Blank cells are present. Author defined 9 45900 ppm (parts per million) 207Pb_235U_ratio The ratio of 207Pb to 235U. Blank cells are present. Author defined 0.02620 6.60000 207Pb_235U_ratio_2sigma 2-sigma (absolute uncertainty) on the ratio of 207Pb to 235U. Blank cells are present. Author defined 0.0006 0.5920 206Pb_238U_ratio The ratio of 206Pb to 238U. Blank cells are present. Author defined 0.0039 0.3735 206Pb_238U_ratio_2sigma 2-sigma (absolute uncertainty) on the ratio of 206Pb to 238U. Blank cells are present. Author defined 0.0001 0.0256 rho_6_38vs7_35 Error correlation coefficient between 206Pb/238U and 207Pb/235U, for generating concordia plot. Blank cells are present. Author defined -0.75 1.00 238U_206Pb_ratio The ratio of 238U to 206Pb. Author defined 2.677 253.970 238U_206Pb_ratio_2sigma 2-sigma (uncertainty) on the ratio of 238U to 206Pb. Author defined 0.076 26.120 207Pb_206Pb_ratio The ratio of 207Pb to 206Pb. Author defined 0.03810 0.53300 207Pb_206Pb_ratio_2sigma 2-sigma (uncertainty) on the ratio of 207Pb to 206Pb. Author defined 0.00098 0.08810 rho_38_6vs7_6 Error correlation coefficient between 238U/206Pb and 207Pb/206Pb, for generating concordia plot. Author defined -1.00 0.91 208Pb_232Th_ratio The ratio of 208Pb to 232Th. Author defined 0.0012 0.1100 208Pb_232Th_ratio_2sigma 2-sigma (uncertainty) on the ratio of 208Pb to 232Th. Author defined 0.0001 0.0270 206Pb_208Pb_ratio The ratio of 206Pb to 208Pb. Author defined 0.74 343.00 206Pb_208Pb_ratio_2sigma 2-sigma (uncertainty) values for the ratio of 206Pb to 208Pb. Author defined 0.06 51.74 207Pb_235U_Age_Ma Age (Ma) calculated from 207Pb/235U ratio. Author defined 26.1 2059.3 Mega-annum, or millions of years before present 207Pb_235U_Age_Ma_2sigma The 2-sigma (uncertainty) in the 207Pb/235U age (Ma). Author defined 0.6 344.9 Mega-annum, or millions of years before present 206Pb_238U_Age_Ma Age (Ma) calculated from 206Pb/238U. Author defined 25.3 2045.8 Mega-annum, or millions of years before present 206Pb_238U_Age_Ma_2sigma The 2-sigma (uncertainty) in the 206Pb/238U age (Ma). Author defined 0.4 148.8 Mega-annum, or millions of years before present 207Pb_206Pb_Age_Ma Age (Ma) calculated from 207Pb/206Pb. Author defined -478.3 4335.2 Mega-annum, or millions of years before present 207Pb_206Pb_Age_Ma_2sigma The 2-sigma (uncertainty) in the 207Pb/206Pb age (Ma). Author defined -66.5 1317.4 Mega-annum, or millions of years before present Concordance Ratio of age determined using 206Pb/238U versus age determined using 207Pb/235U. Author defined 0.13 1.24 Age_Type Method used to calculate the values for each individual analysis that yielded a valid result. "age7corr" indicates a 207Pb-corrected 206Pb/238U age (Ma), for U-Pb ages < 1.4Ga; "agepb76" indicates 207Pb/206Pb age (Ma) for U-Pb ages >1.4Ga. Blank cells indicate no age type determination was made. Author defined age7corr 207Pb-corrected 206Pb/238U age (Ma), for U-Pb ages < 1.4Ga Author defined Preferred_Age Preferred grain age for calculation of sample age (in millions of years, or Ma), selected from one of two following fields containing corrected ages for each grain: 207Pb-corrected 206Pb/238U age (Ma) for U-Pb ages < 1.4Ga; For U-Pb ages > 1.4Ga, or 207Pb/206Pb for U-Pb ages >1.4Ga. Author defined 25.1 2100.7 Mega-annum, or millions of years before present Preferred_Age_2sigma Uncertainty (2-sigma) on preferred grain age (in millions of years, or Ma). Author defined 0.6 141.6 Mega-annum, or millions of years before present 176Hf_177Hf_ratio The ratio of 176Hf to 177Hf. Blank cells are present, indicating no data was measured, and some cells contain the value "-9999.000000", indicating failure of measurement equipment to resolve the data. Author defined 0.281330 0.283340 176Hf_177Hf_ratio_2sigma Uncertainty (2-sigma) values for the ratio of 176Hf to 177Hf. Blank cells are present, indicating no data was measured, and some cells contain the value "-9999.000000", indicating failure of measurement equipment to resolve the data. Author defined 0.000031 0.000320 176Lu_177Hf_ratio The ratio of 176Lu to 177Hf. Blank cells are present, indicating no data was measured, and some cells contain the value "-9999.000000", indicating failure of measurement equipment to resolve the data. Author defined 0.000027 0.013760 176Lu_177Hf_ratio_2sigma Uncertainty (2-sigma) values for the ratio of 176Lu to 177Hf. Blank cells are present, indicating no data was measured, and some cells contain the value "-9999.000000", indicating failure of measurement equipment to resolve the data. Author defined 0.000001 0.001200 178Hf_177Hf_ratio The ratio of 178Hf to 177Hf. Blank cells are present, indicating no data was measured, and some cells contain the value "-9999.000000", indicating failure of measurement equipment to resolve the data. Author defined 1.46685 1.46805 178Hf_177Hf_ratio_2sigma 2-sigma (uncertainty) values for the ratio of 178Hf to 177Hf. Blank cells are present, indicating no data was measured, and some cells contain the value "-9999.000000", indicating failure of measurement equipment to resolve the data. Author defined 0.00006 0.00049 eHf Epsilon Hf value, assuming a chondritic 176Hf/177Hf value of 0.282772 (Blichert-Toft and Albarede, 1997). Blank cells are present, indicating no result was calculated. Author defined -51.00 20.09 eHf_2sigma 2-sigma (uncertainty) values for epsilon Hf value, assuming a chondritic 176Hf/177Hf value of 0.282772 (Blichert-Toft and Albarede, 1997). Blank cells are present, indicating no result was calculated. Author defined 1.10 11.32 176Hf_177Hf_T Age-corrected 176Hf/177Hf ratio, assuming Lutetium-176 decay constant of 1.86x10e-11 (Scherer et al., 2001); not calculated if discordant or no same-grain age measurement. Author defined 0.281441 0.283339 eHf_T Age-corrected epsilon Hf value assuming chondritic 176Hf/177Hf ratio of 0.282772 and 176Lu/177Hf ratio of 0.0332 (Blichert-Toft and Albarede, 1997); not calculated if discordant or no same-grain age measurement. Author defined -36.68 20.83 T_DM_Hf Model age in billions of years before present (Ga) assuming a present-day depleted mantle 176Lu/177Hf and 176Hf/177Hf of 0.0384 and 0.28325 (Griffin et al., 2000). Blank cells are present, indicating no result was calculated. Author defined -0.13 3.03 Giga-annum, or billions of years before present Zr_ppm Zirconium (Zr) concentration, in parts per million (ppm). Blank cells are present. Author defined 3.62E+05 5.39E+05 ppm (parts per million) Zr_cps Raw, uncalibrated signal intensity of zirconium (Zr), measured in counts per second (cps). Provided for informational purposes only. Blank cells are present. Author defined 5.80E+03 9.65E+08 cps (counts per second) Si_ppm Silica (Si) concentration, in parts per million (ppm). Blank cells are present. Author defined 1.29E+05 2.35E+05 ppm (parts per million) Si_cps Raw, uncalibrated signal intensity of silicon (Si), measured in counts per second (cps). Provided for informational purposes only. Blank cells are present. Author defined 3.34E+06 6.62E+07 cps (counts per second) P_ppm Phosphorous (P) concentration, in parts per million (ppm). Blank cells are present. Author defined 39.8 14700.0 ppm (parts per million) Ti_ppm Titanium (Ti) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.69 106000.00 ppm (parts per million) V_ppm Vanadium (V) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.53 1.59 ppm (parts per million) Sr_ppm Strontium (Sr) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.15 0.42 ppm (parts per million) Y_ppm Yttrium (Y) concentration, in parts per million (ppm). Blank cells are present. Author defined 199 23300 ppm (parts per million) Nb_ppm Niobium (Nb) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.25 1963.00 ppm (parts per million) La_ppm Lanthanum (La) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.001 68000.000 ppm (parts per million) Ce_ppm Cerium (Ce) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.6 46000.0 ppm (parts per million) Pr_ppm Praseodymium (Pr) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.01 9800.00 ppm (parts per million) Nd_ppm Neodymium (Nd) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.2 19100.0 ppm (parts per million) Sm_ppm Samarium (Sm) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.3 1970.0 ppm (parts per million) Eu_ppm Europium (Eu) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.02 117.00 ppm (parts per million) Gd_ppm Gadolinium (Gd) concentration, in parts per million (ppm). Blank cells are present. Author defined 2.3 1840.0 ppm (parts per million) Tb_ppm Terbium (Tb) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.9 331.0 ppm (parts per million) Dy_ppm Dysprosium (Dy) concentration, in parts per million (ppm). Blank cells are present. Author defined 13.4 2700.0 ppm (parts per million) Ho_ppm Holmium (Ho) concentration, in parts per million (ppm). Blank cells are present. Author defined 5.7 781.0 ppm (parts per million) Er_ppm Erbium (Er) concentration, in parts per million (ppm). Blank cells are present. Author defined 30 3560 ppm (parts per million) Tm_ppm Thulium (Tm) concentration, in parts per million (ppm). Blank cells are present. Author defined 8.6 923.0 ppm (parts per million) Yb_ppm Ytterbium (Yb) concentration, in parts per million (ppm). Blank cells are present. Author defined 83 7660 ppm (parts per million) Lu_ppm Lutetium (Lu) concentration, in parts per million (ppm). Blank cells are present. Author defined 14.9 7660.0 ppm (parts per million) Hf_ppm Hafnium (Hf) concentration, in parts per million (ppm). Author defined 2 28469 ppm (parts per million) Ta_ppm Tantalum (Ta) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.166 457.000 ppm (parts per million) Pb_ppm Lead (Pb) concentration, in parts per million (ppm). Blank cells are present. Author defined 0.7 1570.0 ppm (parts per million) T_C Ti-in-zircon thermometer (degrees C), after Ferry and Watson (2007), assuming SiO2 and TiO2 of 0.7. Blank cells are present, indicating no calculation for grains excluded from main populations. Author defined 567 931 degrees Celsius Supplemental_Info_Analytical_Methods_UCSB_LASS.pdf "Supplemental Info: Zircon U-Pb geochronology, Hf isotope and trace element concentration analytical methods using UCSB Laser-ablation Split Stream (LASS) Analysis": Document that describes the laboratory methods used in Laser Ablation Split-Stream (LASS) procedures. Provided in PDF format. Author defined U.S. Geological Survey USGS ScienceBase Team Mailing and Physical

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