The bivariate plot of Ague provides

Moreover methanogens is often used in mass balance studies (e.g., Birkeland, 1999, Brimhall and Dietrich, 1987 and Girty et al., 2008; and many others). Consequently, though Ca, Mg, and Na yielded broadly similar results, we report here only the results derived from using Zr as the reference frame.
The key algorithm in SACD is based on the following equation for a change in elemental mass (Δ%elemental mass) derived originally by Woronow and Love (1990).equation(2)Δ%elementalmass=100elnfm−1.