Data Release for Hydrocarbons in Upland Groundwater, Marcellus Shale Region, Northeastern Pennsylvania and Southern New York, USA

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.

                                            [
  "010:12"
]
                                        

                                            {
  "fn": "Peter B McMahon",
  "@type": "vcard:Contact",
  "hasEmail": "mailto:pmcmahon@usgs.gov"
}
                                        

                                            [
  {
    "@type": "dcat:Distribution",
    "title": "Digital Data",
    "format": "XML",
    "accessURL": "https://doi.org/10.5066/P93M7JCD",
    "mediaType": "application/http",
    "description": "Landing page for access to the data"
  },
  {
    "@type": "dcat:Distribution",
    "title": "Original Metadata",
    "format": "XML",
    "mediaType": "text/xml",
    "description": "The metadata original format",
    "downloadURL": "https://data.usgs.gov/datacatalog/metadata/USGS.5c58ad28e4b0708288ff2ab6.xml"
  }
]
                                        

                                            [
  "Bradford County, PA",
  "Broome County, NY",
  "Cycle 3",
  "Domestic well",
  "Groundwater",
  "Groundwater-age distribution",
  "Hydrocarbons",
  "Marcellus Shale",
  "NAWQA",
  "New York",
  "Pennsylvania",
  "Shale-gas well",
  "Sullivan County, PA",
  "Susquehanna County, PA",
  "Tioga County, NY",
  "USGS:5c58ad28e4b0708288ff2ab6",
  "Water quality",
  "Wyoming County, PA"
]
                                        

                                            {
  "name": "U.S. Geological Survey",
  "@type": "org:Organization"
}
                                        

                                            [
  "Geospatial"
]