This dataset contains measurements of dissolved hydrocarbons in from groundwater samples collected in the shale gas producing regions of West Virginia, USA, between June and August of 2018. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6). This dataset also contains corresponding measurements of chlorofluorocarbons (CFCs), Sulfurhexafluoride (SF6), dissolved permanent gases (N2/Ar), tritium, the isotope ratio of helium dissolved in water, the concentration of neon dissolved in water, the isotope ratios of hydrogen-2 and oxygen-18 in water, and the isotope ratio of carbon-13 in dissolved inorganic carbon (DIC).

This dataset contains measurements of dissolved hydrocarbons in from various water sources, as well as ancillary raw calibration data showing the stability of the gas chromatograph with an atomic emission detector and flame ionization detector (GC-AED-FID) analytical system over time. Across multiple studies, samples from tap water, groundwater, surface water, springs, mine outflows, and blank materials were analyzed using this system over a period from 2014 to 2017, comprising 172 samples analyzed. In addition to water samples, 183 calibrations conducted over the same period of time are included to document the stability of the GC-AED-FID system over time. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6).

This dataset contains measurements of dissolved hydrocarbons in from various water sources, as well as ancillary raw calibration data showing the stability of the gas chromatograph with an atomic emission detector and flame ionization detector (GC-AED-FID) analytical system over time. Across multiple studies, samples from tap water, groundwater, surface water, springs, mine outflows, and blank materials were analyzed using this system over a period from 2014 to 2017, comprising 172 samples analyzed. In addition to water samples, 183 calibrations conducted over the same period of time are included to document the stability of the GC-AED-FID system over time. The target analytes in this study were: methane (CH4), ethane (C2H6), ethene (C2H4), ethyne (C2H2), propane (C3H8), propene (C3H6), i-butane (C4H10), n-butane (C4H10), 1-butene (C4H8), propyne (C3H4), i-pentane (C5H12), n-pentane (C5H12), 2-methyl-pentane (C6H14), 3-methyl-pentane (C6H14), hexane (C6H14), and benzene (C6H6).

Water samples from 50 domestic wells located <1 kilometer (km) (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas compared to valleys. Methane (CH4) -isotope and pre-drill CH4 data indicate one proximal sample (5 percent of proximal samples) contains thermogenic CH4 (2.6 milligrams per liter (mg/L)) associated with shale-gas production. Chloride (Cl), bromide (Br), lithium (Li), and neon-20 (20Ne)/argon-36 (36Ar) data suggest that CH4 leaked from a nearby gas well in a gas phase. Another proximal sample contains volatile hydrocarbons (0.03-0.4 micrograms per liter (µg/L)), including benzene, found in some hydraulic fracturing fluid. Modeled groundwater-age distributions, calibrated to tritium (3H), sulfur hexafluoride (SF6), and carbon-14 (14C) concentrations, indicate that water recharged prior to shale-gas development, suggesting surface releases associated with shale-gas production were not the source of those hydrocarbons, although leakage from a nearby gas well directly into the old groundwater cannot be ruled out. Estimated age distributions in the samples span ~20 to >10,000 years and have implications for relating occurrences of hydrocarbons in groundwater to surface releases associated with recent shale-gas production, and to the time required to flush contaminants from the system. This data release contains isotopic tracer, noble gas, and groundwater-age tracer concentration data collected by the U.S. Geological Survey and data for pH, specific conductance, major ions, and methane collected by Chesapeake Energy Corporation.

Water samples from 50 domestic wells located <1 kilometer (km) (proximal) and >1 km (distal) from shale-gas wells in upland areas of the Marcellus Shale region were analyzed for chemical, isotopic and groundwater-age tracers. Uplands were targeted because natural mixing with brine and hydrocarbons from deep formations is less common in those areas compared to valleys. Methane (CH4) -isotope and pre-drill CH4 data indicate one proximal sample (5 percent of proximal samples) contains thermogenic CH4 (2.6 milligrams per liter (mg/L)) associated with shale-gas production. Chloride (Cl), bromide (Br), lithium (Li), and neon-20 (20Ne)/argon-36 (36Ar) data suggest that CH4 leaked from a nearby gas well in a gas phase. Another proximal sample contains volatile hydrocarbons (0.03-0.4 micrograms per liter (µg/L)), including benzene, found in some hydraulic fracturing fluid. Modeled groundwater-age distributions, calibrated to tritium (3H), sulfur hexafluoride (SF6), and carbon-14 (14C) concentrations, indicate that water recharged prior to shale-gas development, suggesting surface releases associated with shale-gas production were not the source of those hydrocarbons, although leakage from a nearby gas well directly into the old groundwater cannot be ruled out. Estimated age distributions in the samples span ~20 to >10,000 years and have implications for relating occurrences of hydrocarbons in groundwater to surface releases associated with recent shale-gas production, and to the time required to flush contaminants from the system. This data release contains isotopic tracer, noble gas, and groundwater-age tracer concentration data collected by the U.S. Geological Survey and data for pH, specific conductance, major ions, and methane collected by Chesapeake Energy Corporation.

This data release documents three Microsoft Excel tables that contain data for understanding environmental tracer concentrations in groundwater of the Columbia Plateau 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.

This data release documents three Microsoft Excel tables that contain data for understanding environmental tracer concentrations in groundwater of the Columbia Plateau 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.

This data release contains geochemical and mineralogical laboratory results from core samples collected from the USGS Cow Creek 1-21 well. The well was drilled and cored in 2022 and targeted the Lewis Shale on the eastern edge of the Washakie Basin in Carbon County, Wyoming. The core data include results from total organic carbon (TOC) and total carbon (TC) analysis, programmed pyrolysis, inductively coupled plasma-optical emission spectroscopy and mass spectrometry (ICP-OES/MS), X-ray diffraction (XRD), stable isotope (C-13) analysis, and vitrinite reflectance analysis. A separate data release contains 4 geophysical wire line logs and is available at .

In 2023, the U.S. Geological Survey, in cooperation with Riverside Energy Michigan, LLC, conducted an injection experiment to monitor the natural rate of biogenic methane generation in the Mortensen A4-24 well which was completed in the Antrim Shale and located in Antrim County, Michigan, United States of America. Approximately 20 barrels (bbl) of produced water was pumped from the well and stored in a tank in the weeks prior to the injection. On June 6, 2023, ~15 bbl of produced water from the tank was mixed with 2 L of deuterated water (D2O) in a pump truck and injected into the Mortensen A4-24 well. An additional ~5 bbl of produced water from the tank was injected to push the D2O labeled slug into the formation. The well was shut in (both gas and produced water) until August 29, 2023. Produced water and gas samples were collected prior to the injection to assess background conditions and after the shut-in period to assess changes to the system due to the injection. Gas samples were also collected during the shut-in period. This data set includes the geochemical analyses of the produced water samples collected, the compositional and isotopic data of the gas sampled, and metaproteomic data synthesized from extraction of filtered particulates.

In 2023, the U.S. Geological Survey, in cooperation with Riverside Energy Michigan, LLC, conducted an injection experiment to monitor the natural rate of biogenic methane generation in the Mortensen A4-24 well which was completed in the Antrim Shale and located in Antrim County, Michigan, United States of America. Approximately 20 barrels (bbl) of produced water was pumped from the well and stored in a tank in the weeks prior to the injection. On June 6, 2023, ~15 bbl of produced water from the tank was mixed with 2 L of deuterated water (D2O) in a pump truck and injected into the Mortensen A4-24 well. An additional ~5 bbl of produced water from the tank was injected to push the D2O labeled slug into the formation. The well was shut in (both gas and produced water) until August 29, 2023. Produced water and gas samples were collected prior to the injection to assess background conditions and after the shut-in period to assess changes to the system due to the injection. Gas samples were also collected during the shut-in period. This data set includes the geochemical analyses of the produced water samples collected, the compositional and isotopic data of the gas sampled, and metaproteomic data synthesized from extraction of filtered particulates.