Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.
Plots of (a) δ18O and (b) δ13CDIC against the C1 14C age in intermediate and deep groundwater only (samples from >90 m bgl), with an added third dimension of alkalinity. The units of alkalinity concentrations shown in the legend are mEq/L, and the three concentration ranges were selected based on the spread of data values. The overall trendlines for pooled intermediate and deep samples and their R2 values are displayed.
