TY - JOUR
T1 - Tritium-helium 3 dating under complex conditions in hydraulically stressed areas of a buried-valley aquifer
AU - Shapiro, Stephanie Dunkle
AU - Rowe, Gary
AU - Schlosser, Peter
AU - Ludin, Andrea
AU - Stute, Martin
PY - 1998/5
Y1 - 1998/5
N2 - The 3H-3He dating method is applied in a buried-valley aquifer near Dayton, Ohio. The study area is large, not all sampling locations lie along well-defined flow paths, and existing wells with variable screen lengths and diameters are used. Reliable use of the method at this site requires addressing several complications: (1) The flow system is disturbed because of high pumping rates and induced infiltration; (2) tritium contamination is present in several areas of the aquifer; and (3) radiogenic helium concentrations are elevated in a significant number of the wells. The 3H-3He ages are examined for self-consistency by comparing the reconstructed tritium evolution to the annual weighted tritium measured in precipitation; deviations result from dispersion, tritium contamination, and mixing. The 3H-3He ages are next examined for consistency with chlorofluorocarbon ages, the agreement is poor because of degradation of CFCs. Finally, the 3H-3He ages are examined for consistency with the current understanding of local hydrologic processes; the ages are generally supported by hydrogeologic data and the results of groundwater flow modeling coupled with particle-tracking analyses.
AB - The 3H-3He dating method is applied in a buried-valley aquifer near Dayton, Ohio. The study area is large, not all sampling locations lie along well-defined flow paths, and existing wells with variable screen lengths and diameters are used. Reliable use of the method at this site requires addressing several complications: (1) The flow system is disturbed because of high pumping rates and induced infiltration; (2) tritium contamination is present in several areas of the aquifer; and (3) radiogenic helium concentrations are elevated in a significant number of the wells. The 3H-3He ages are examined for self-consistency by comparing the reconstructed tritium evolution to the annual weighted tritium measured in precipitation; deviations result from dispersion, tritium contamination, and mixing. The 3H-3He ages are next examined for consistency with chlorofluorocarbon ages, the agreement is poor because of degradation of CFCs. Finally, the 3H-3He ages are examined for consistency with the current understanding of local hydrologic processes; the ages are generally supported by hydrogeologic data and the results of groundwater flow modeling coupled with particle-tracking analyses.
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U2 - 10.1029/97WR03322
DO - 10.1029/97WR03322
M3 - Article
AN - SCOPUS:0031961422
SN - 0043-1397
VL - 34
SP - 1165
EP - 1180
JO - Water Resources Research
JF - Water Resources Research
IS - 5
ER -