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.

Twenty-five ore and gangue mineral separates from the Miocene-age Goldfield and Tonopah epithermal Au-Ag deposits in southwestern Nevada were analyzed to determine the helium, neon, and argon (He, Ne, and Ar) isotopic compositions contained in fluid inclusions. Four mineral separates from the Butte Main Stage vein deposit and two from the Bingham pyrite-enargite vein deposits were also analyzed. Fifteen separates are from hand samples collected from underground mine workings and the remaining 16 are from mine tailings piles and pits excavated within the past 100 years. The separates consist dominantly of pyrite, enargite, and quartz, with lesser amounts of sphalerite, galena, potassium feldspar, bismuthinite, marcasite, alunite, chalcocite, chalcopyrite, rhodonite, and gold. Fluid inclusion gases were extracted by thermal decrepitation at 300 to 350°C, with the exception of samples CL-480 and M2763A which were crushed under ultrahigh vacuum. Ar and Ne isotopic ratios are similar to atmospheric compositions while He isotopic ratios (helium-3/helium-4 [3He/4He]) range widely from 0.03 to 34.12 times the atmospheric 3He/4He value (R/RA, measured 3He/4He normalized to the atmospheric value of 1.384 x 10^-6).

Twenty-five ore and gangue mineral separates from the Miocene-age Goldfield and Tonopah epithermal Au-Ag deposits in southwestern Nevada were analyzed to determine the helium, neon, and argon (He, Ne, and Ar) isotopic compositions contained in fluid inclusions. Four mineral separates from the Butte Main Stage vein deposit and two from the Bingham pyrite-enargite vein deposits were also analyzed. Fifteen separates are from hand samples collected from underground mine workings and the remaining 16 are from mine tailings piles and pits excavated within the past 100 years. The separates consist dominantly of pyrite, enargite, and quartz, with lesser amounts of sphalerite, galena, potassium feldspar, bismuthinite, marcasite, alunite, chalcocite, chalcopyrite, rhodonite, and gold. Fluid inclusion gases were extracted by thermal decrepitation at 300 to 350°C, with the exception of samples CL-480 and M2763A which were crushed under ultrahigh vacuum. Ar and Ne isotopic ratios are similar to atmospheric compositions while He isotopic ratios (helium-3/helium-4 [3He/4He]) range widely from 0.03 to 34.12 times the atmospheric 3He/4He value (R/RA, measured 3He/4He normalized to the atmospheric value of 1.384 x 10^-6).

Geochemical data for cold groundwaters and produced geothermal fluids around the Utah FORGE site. The data is compiled into four tables in the attached Excel File. Table 1 is a compilation of compositions (anions, cations, weak acids, oxygen, hydrogen, and carbon isotopes) for cold groundwaters and produced geothermal waters in the Milford valley, Utah. Table 2 is a compilation of noble gas (He, Ne, Ar) and He and Ne isotopic compositions for cold groundwaters and produced geothermal waters in the Milford valley, Utah. Table 3 provides values for calculated advective and diffusive fluxes of helium. Table 4 provides values of calculated subsurface stored heat between the Opal Mound fault and the Utah FORGE site, which are related to volumes of recently solidified magmatic heat sources.

Geochemical data for cold groundwaters and produced geothermal fluids around the Utah FORGE site. The data is compiled into four tables in the attached Excel File. Table 1 is a compilation of compositions (anions, cations, weak acids, oxygen, hydrogen, and carbon isotopes) for cold groundwaters and produced geothermal waters in the Milford valley, Utah. Table 2 is a compilation of noble gas (He, Ne, Ar) and He and Ne isotopic compositions for cold groundwaters and produced geothermal waters in the Milford valley, Utah. Table 3 provides values for calculated advective and diffusive fluxes of helium. Table 4 provides values of calculated subsurface stored heat between the Opal Mound fault and the Utah FORGE site, which are related to volumes of recently solidified magmatic heat sources. The associated paper for this study will be open access (Simmons, S.F., and Kirby, S. 2024. Formation of a Large Cold Groundwater Mantle Helium Anomaly and High Temperature Geothermal Resources in Response to Bimodal Magmatism near Roosevelt Hot Springs and Utah FORGE, Milford Valley, southwest Utah. Geochemistry, Geophysics, Geosystems, in press.).

This data release provides quantitative whole rock geochemical results from The Geysers vapor-dominated geothermal field in California. The concentrations of major elements are reported in oxide weight percent by wavelength dispersive x-ray fluorescence (WDXRF), the concentrations for sixty elements are reported in elemental weight percent (pct) or parts per million (ppm) from inductively coupled plasma-optical emission spectrometry-mass spectrometry ICP-OES-MS analysis, mercury is reported in ppm by cold vapor atomic absorption spectrometry (CVAAS), and ammonium in ppm from automated colorimetry analysis. The analyses show significant enrichment of volatile elements and elements such as sulfur, boron, arsenic, and mercury. Mineral scales from the Northwest Geysers are characterized by high concentrations of ammonium and mercury while the mineral scales from the Central and Southeast Geysers are enriched in boron, iron and sulfur. The mineral scales from orifice plates and condensers contain significant concentrations of Cr, Ni, Co, Zn, and W which are common contaminants from rusted steel equipment.

This dataset contains 8 data tables provided in .csv format that contain sample location data, whole-rock geochemical data, argon-argon geochronologic data, sulfur, oxygen, and hydrogen isotope data, and mineralogical data from shortwave infrared spectrography (SWIR) and X-ray diffraction (XRD) analyses collected from igneous rocks on Brokeoff and Maidu volcanoes, northeastern California, USA. The data table files are Sample_Location_Data.csv, Argon_Data.csv, Geochemistry_Data.csv, SWIR_Data.csv, Whole_Rock_XRD.csv, Clay_XRD.csv, Sulfur_Isotope.csv, and Oxygen_Hydrogen_Data.csv. Fields in the data tables are defined in 8 corresponding data dictionaries, Sample_Location_Data_Dictionary.csv, Argon_Data_Dictionary.csv, Geochemistry_Data_Dictionary.csv, Whole_Rock_XRD_Dictionary.csv, Clay_XRD_Data_Dicitonary.csv, Sulfur_Isotope_Data_Dictionary.csv, Oxygen_Hydrogen_Isotope_Data_Dictionary.csv, and SWIR_Data Dictionary.csv. Analytical techniques are described in AnalyticalTechniques.txt.

This dataset contains 8 data tables provided in .csv format that contain sample location data, whole-rock geochemical data, argon-argon geochronologic data, sulfur, oxygen, and hydrogen isotope data, and mineralogical data from shortwave infrared spectrography (SWIR) and X-ray diffraction (XRD) analyses collected from igneous rocks on Brokeoff and Maidu volcanoes, northeastern California, USA. The data table files are Sample_Location_Data.csv, Argon_Data.csv, Geochemistry_Data.csv, SWIR_Data.csv, Whole_Rock_XRD.csv, Clay_XRD.csv, Sulfur_Isotope.csv, and Oxygen_Hydrogen_Data.csv. Fields in the data tables are defined in 8 corresponding data dictionaries, Sample_Location_Data_Dictionary.csv, Argon_Data_Dictionary.csv, Geochemistry_Data_Dictionary.csv, Whole_Rock_XRD_Dictionary.csv, Clay_XRD_Data_Dicitonary.csv, Sulfur_Isotope_Data_Dictionary.csv, Oxygen_Hydrogen_Isotope_Data_Dictionary.csv, and SWIR_Data Dictionary.csv. Analytical techniques are described in AnalyticalTechniques.txt.

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.