Pilot Project on Groundwater Dating in Confined Aquifers of the North Carolina Coastal Plain

摘要

This pilot project presents 14C groundwater ages in the Black Creek and Upper Cape Fear aquifers of the North Carolina Coastal Plain, an evaluation of the relationship between He concentration and groundwater age, and H concentrations in groundwater. Groundwater samples were collected with a positive-displacement Bennett pump from 7 wells that lie along a trend roughly; parallel to groundwater flow (at least, predevelopment groundwater flow). 14C, 13C, DIC,:DOC, He, Ne,.Ar, N(sub 2), O(sub 2), CO2, CH4, H2, (sup 3)H, S, Fe, Al, Mn, Si, Na+, K+, Ca2+, Mg 2+, Cl-, SO4-, and NO3- were measured in all samples. Estimation of groundwater age involved inverse mass balance modeling with NETPATH to account for geochemical reactions (calcite dissolution, organic matter oxidation, and cation exchange) affecting 14C activity in groundwater.