This data release documents three Microsoft Excel tables; one contains noble gas isotopic data, one contains data for understanding groundwater ages in the South Rim of the Grand Canyon, and one that describe the data fields. Results described include raw noble gas concentrations, environmental tracer concentrations (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14, and chlorofluorocarbons), and mean age and age distribution. Noble gas isotopes (NobleGas) contain noble gas isotope concentrations measured for South Rim springs. Samples were collected in pinch clousure copper tubes (Weiss, 1968) and analyzed at the University of Utah Dissolved Gas Lab. Mean age and age distribution results (TracerLPM) contain final models of groundwater age by calibration of lumped parameter models to tracer concentrations (Jurgens and others, 2012). In cases where age was modeled with a binary lumped parameter model (BMM), the mean age was computed from the mean age and fraction of the two components in the mixture. Please see the processing steps below and the main manuscript for additional details on the results presented in this table. Multiple LPMs are provided for a single sample to estimate uncertainty in mean age and age distribution associated with LPM parameter estimates.

This data release documents 155 sets of dissolved noble gas analyses (neon, argon, krypton, xenon) and 153 modeled recharge temperatures for groundwater sampled from domestic water supply wells and springs throughout the northern Sierra Nevada foothills as part of the California State Water Resources Control Board’s Groundwater Ambient Monitoring and Assessment (GAMA) Program in 2015-2017. Data from two of the U.S. Geological Survey’s Priority Basin Project Shallow Aquifer Assessment study units are presented here: The Yuba and Bear Watersheds (YB) Shallow Aquifer Study Unit (sampled in 2015-2016) and the Mokelumne, Cosumnes, and American River Watersheds (MCAW) Shallow Aquifer Study Unit (sampled in 2016-2017). The YB and MCAW study units include domestic well and spring sites within watersheds overlying fractured rock aquifer systems of the Sierra Nevada hydrogeologic province of California in Nevada, Yuba, Sierra, Placer, El Dorado, Amador, and Calaveras Counties. Study design and site attributes for the YB and MCAW study units are presented by Jasper and others (2017) and Shelton and others (2018), respectively. This data release contains one tab-delimited text file containing Table 1, which reports the results of dissolved noble gas analyses for environmental samples from 72 sites in the YB study unit in addition to eight field replicates (80 samples total) and environmental samples from 67 sites in the MCAW study unit in addition to eight field replicates (75 samples total). Table 1 also contains groundwater recharge temperatures for 153 samples that were modeled using measured dissolved noble gas concentrations, land surface elevation at the sample site, and sample salinity. Model inputs and outputs including Monte Carlo simulations to estimate model parameter errors are also included in Table 1. Detailed descriptions for Table 1 column fields are provided in an additional tab-delimited text file of Table 1 column definitions. Abbreviations used in this data release are explained in an additional tab-delimited text file of abbreviations. These data support the following publications: Jasper, M., Bennett, G.L., and Fram, M.S., 2017, Groundwater-Quality Data in the Yuba and Bear Watersheds Shallow Aquifer Study Unit, 2015-2016: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release, https://doi.org/10.5066/F73F4MS9. Levy, Z.F., Fram, M.S., Faulkner, K.E., Alpers, C.N., Soltero, E.M., and Taylor, K.A., 2020, Effects of montane watershed development on vulnerability of domestic groundwater supply during drought: Journal of Hydrology, v. 583, https://doi.org/10.1016/j.jhydrol.2020.124567. Shelton, J.L., Fram, M.S., Goldrath, D.A., Bennett, G.L., V, and Jasper, M., 2018, Groundwater-quality data in the Mokelumne, Cosumnes, and American River Watersheds Shallow Aquifer Study Unit, 2016-2017: Results from the California GAMA Priority Basin Project: U.S. Geological Survey data release, https://doi.org/10.5066/F78G8JXP.

This dataset provides groundwater age estimates for 203 wells used as public- and domestic-supply in two selected areas of California. Groundwater ages were estimated by calibration of environmental tracers (tritium, tritiogenic helium-3, sulfur hexafluoride, carbon-14 and radiogenic helium-4) to lumped parameter models (LPMs). Calibrated lumped parameter models provide the optimal mean age and mixing parameter(s) used to compute the distribution of ages that explain the measured tracer concentrations in a sample. Groundwater samples were collected between March 2006 and October 2022 as part of four studies done for the California Groundwater Ambient Monitoring and Assessment Priority Basin Project (GAMA-PBP): (1) Central Eastside San Joaquin Basin public-supply, (2) South Coast Interior Basins - Gilroy public-supply, (3) Modesto, Turlock, and Merced subbasins of the San Joaquin Valley groundwater basin domestic-supply, and (4) Gilroy-Hollister groundwater basin and adjacent areas outside of the basin domestic-supply. Table 1 reports the primary results of this assessment including mean groundwater age, linear recharge rate, groundwater age classification based on tritium, condensed results from dissolved gas modeling, and calculated environmental tracer concentrations. Tables 2, 3, and 4 provide results in support of Table 1. Table 2 reports detailed results for the calibration of dissolved gas models to neon, argon, krypton, xenon, and nitrogen. Calibrated dissolved gas models provide the optimal water temperature, excess air, entrapped air, fractionation of gases, and excess nitrogen gas (mainly from denitrification) that explain the measured dissolved gases in a sample. Table 3 reports measured concentrations and the detailed calculations of environmental tracer concentrations derived from the dissolved gas modeling results in Table 2. Calculated concentrations of environmental tracers that can be used in groundwater age calculations are the dry air mixing ratio of sulfur hexafluoride, tritiogenic helium-3, which is the concentration of helium-3 from the decay of tritium, and radiogenic helium-4. Table 4 reports information used to calculate carbon-14 dilution for use in groundwater age calculations. In addition to these five tables, two ancillary tables (Table 5 and Table 6) are included to provide more detailed information about the fields and the abbreviations used in Tables 1-4.

The contents of this data release represent the results of the noble gas composition analysis and are presented in support of the planned publication Gao et al., 2023, titled Lead and noble gas isotopic constraints on the origin of Te-bearing adularia-sericite epithermal Au-Ag deposits in a calc-alkaline magmatic arc. Tellurium (Te)-bearing adularia-sericite epithermal Au-Ag deposits are widely distributed in calc-alkaline magmatic arcs and are an important current and future source of precious and critical metals. However, the source of ore-forming fluids in these deposits remain unclear due to the lack of isotopic evidence on Au-, Ag-, and Te-bearing minerals. To advance understanding of the source of Te and precious metals, He, Ne, and Ar isotope analysis were performed on gases extracted from fluid inclusions contained in ore and gangue minerals from two Te-rich (Sandaowanzi and Yongxin, Xing’an Block) and two Te-poor (Dong’an, Songliao Block, and Tuanjiegou, Jiamusi Massif) epithermal Au-Ag deposits that occur in an early Cretaceous magmatic arc in the North Heilongjiang Belt, northeastern China. Samples were collected by Shen Gao (see Gao et al. 2022) and were analyzed at the U.S. Geological Survey Noble Gas Laboratory by Andrew Hunt from August 2019 to March 2020.

The contents of this data release represent the results of the noble gas composition analysis and are presented in support of the planned publication Gao et al., 2023, titled Lead and noble gas isotopic constraints on the origin of Te-bearing adularia-sericite epithermal Au-Ag deposits in a calc-alkaline magmatic arc. Tellurium (Te)-bearing adularia-sericite epithermal Au-Ag deposits are widely distributed in calc-alkaline magmatic arcs and are an important current and future source of precious and critical metals. However, the source of ore-forming fluids in these deposits remain unclear due to the lack of isotopic evidence on Au-, Ag-, and Te-bearing minerals. To advance understanding of the source of Te and precious metals, He, Ne, and Ar isotope analysis were performed on gases extracted from fluid inclusions contained in ore and gangue minerals from two Te-rich (Sandaowanzi and Yongxin, Xing’an Block) and two Te-poor (Dong’an, Songliao Block, and Tuanjiegou, Jiamusi Massif) epithermal Au-Ag deposits that occur in an early Cretaceous magmatic arc in the North Heilongjiang Belt, northeastern China. Samples were collected by Shen Gao (see Gao et al. 2022) and were analyzed at the U.S. Geological Survey Noble Gas Laboratory by Andrew Hunt from August 2019 to March 2020.

Dissolved noble gas data were collected using a portable mass spectrometer mounted on inflatable rafts on the Colorado River near Glenwood Springs, Colorado and the Virgin River near La Verkin, Utah. Data were collected approximately every 3 to 10 minutes for a suite of noble gases including helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). Patterns in observed dissolved He concentrations were used to locate diffuse discharge of saline geothermal water, which commonly have elevated He concentrations. Diffuse groundwater discharge can be difficult to locate and quantify, and the dissolved He signals are a novel approach to understanding diffuse geothermal discharge to rivers. Dissolved He data were also used in a mass balance model to estimate the quantity of discharging groundwater.

Dissolved noble gas data were collected using a portable mass spectrometer mounted on inflatable rafts on the Colorado River near Glenwood Springs, Colorado and the Virgin River near La Verkin, Utah. Data were collected approximately every 3 to 10 minutes for a suite of noble gases including helium (He), neon (Ne), argon (Ar), krypton (Kr), and xenon (Xe). Patterns in observed dissolved He concentrations were used to locate diffuse discharge of saline geothermal water, which commonly have elevated He concentrations. Diffuse groundwater discharge can be difficult to locate and quantify, and the dissolved He signals are a novel approach to understanding diffuse geothermal discharge to rivers. Dissolved He data were also used in a mass balance model to estimate the quantity of discharging groundwater.

This data release documents two Microsoft Excel tables that contain data for understanding tracer concentrations and groundwater age in the Columbia Plateau aquifer system. Results for geochemical correction of carbon-14, and lumped parameter modeling of groundwater age for the sample network (VPFS, vertical flow path study) are described. Geochemical carbon-14 correction results (RFG) describe geochemical correction of carbon-14 in dissolved inorganic carbon (DIC) for groundwater age dating. Datasets includes measured water parameters and chemistry, model parameter inputs, and final corrected carbon-14 in DIC. Geochemical correction was completed using the revised Fontes and Granier model of Han and Plummer (2013). Mean age and age distribution results (TracerLPM) contain final models of groundwater age by calibration of lumped parameter models to tracer concentrations (Jurgens and others, 2012). Please see the processing steps below for additional details on the results presented in this table.

This data release documents two Microsoft Excel tables that contain data for understanding tracer concentrations and groundwater age in the Columbia Plateau aquifer system. Results for geochemical correction of carbon-14, and lumped parameter modeling of groundwater age for the sample network (VPFS, vertical flow path study) are described. Geochemical carbon-14 correction results (RFG) describe geochemical correction of carbon-14 in dissolved inorganic carbon (DIC) for groundwater age dating. Datasets includes measured water parameters and chemistry, model parameter inputs, and final corrected carbon-14 in DIC. Geochemical correction was completed using the revised Fontes and Granier model of Han and Plummer (2013). Mean age and age distribution results (TracerLPM) contain final models of groundwater age by calibration of lumped parameter models to tracer concentrations (Jurgens and others, 2012). Please see the processing steps below for additional details on the results presented in this table.

This data release documents three Microsoft Excel tables that contain data for understanding environmental tracer concentrations in groundwater of the High Plains aquifer system. Results of dissolved-gas modeling using environmental tracer concentrations (tritium, tritiogenic helium-3, and radiogenic helium-4), for the sample network (VPFS, vertical flow path study) are described. Dissolved gas modeling results (ModOut) contains detailed information on the calibration of dissolved gas models to measured dissolved-gas concentrations (neon, argon, krypton, xenon, and nitrogen). Calibration was done using methods described by Aeschbach-Hertig and others (1999 & 2000) with modifications to include nitrogen gas (Weiss, 1970). In most cases, a single set of noble-gas concentrations (neon, argon, krypton, and xenon) was used to solve for recharge conditions (recharge temperature, excess or entrapped air, and fractionation) using the unfractionated excess air (UA) and closed equilibration (CE) models (Aeschbach-Hertig and others, 1999 & 2000). In cases where noble gas data were not available, multiple analyses of nitrogen and argon (collected sequentially on the same sample date) were used to solve for recharge conditions. Environmental tracer results (TrcOut) contains detailed information on calculations of environmental tracer data. Dissolved gas models were paired with measured helium isotope ratios (3He/4He) and helium concentrations to calculate concentrations of tritiogenic helium-3 (the component of 3He derived from tritium decay; Solomon and Cook, 2000) and radiogenic helium-4 (the component of 4He derived from the decay of uranium and thorium in aquifer materials; Solomon, 2000). Tracer concentrations were computed for each combination of measure dissolved gas concentrations when sites had multiple measured gas results and analyses for helium isotopes. Average environmental tracer results (AvgTrcOut) contains average tracer concentrations for a given site used for determination of groundwater ages. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (1999), Interpretation of dissolved atmospheric noble gases in natural waters, Water Resour. Res., 35(9), 2779–2792,https://dx.doi.org/10.1029/1999WR900130. Aeschbach-Hertig, W., F. Peeters, U. Beyerle, and R. Kipfer (2000), Paleotemperature reconstruction from noble gases in ground water taking into account equilibration with entrapped air, Nature, v. 405, Iss. 6790, pg. 1040-1044, http://dx.doi.org/10.1038/35016542 Solomon, D.K., and P.G. Cook. 2000. 3H and 3He. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 197-424. Boston: Kluwer Academic Publishers. Solomon, D.K. 2000. 4He in groundwater. In Environmental Tracers in Subsurface Hydrology, ed. P.G. Cook and A.L. Herczeg, 425-439. Boston: Kluwer Academic Publishers. Weiss, R. F., 1970, The solubility of nitrogen, oxygen, and argon in water and seawater, Deep Sea Research, vol. 17, pp. 721-735, https://doi.org/10.1016/0011-7471(70)90037-9.