Figure 4
(a) A dissolution sensitivity diagram, which shows the dissolution rates of minerals and selected glasses as function of nc at pH 13 (0.15 M NaOH); a concrete relevant pH (T = 25° ± 3 °C, p = 1 bar). Dissolution sensitivities of more covalently bonded silicate minerals increase with a decreasing number of atomic constraints (nc). Decreasing nc often denotes an increase in atomic disorder, e.g., as induced by irradiation. More ionically bonded minerals such as calcite show little if any change in nc and dissolution rates following irradiation (Fig. 1b). Rate data for glasses compositionally analogous to albite, jadeite and nepheline was sourced from the literature50 while all other rate data was measured using VSI. The thick dashed lines show the trends in dissolution rates while the thin solid lines show relevant uncertainty bounds. The trend line is fitted to an equation of the form: DR = A · exp(B · nc), where A and B are numerical constants. The highest uncertainty in the measured dissolution rate(s) is on the order of ±0.5 log units. (b) 3D VSI images of a (100)-surface of irradiated quartz: (i) prior to its dissolution and (ii) after 22 hours of dissolution at pH 14.6. The cross section profile (ii) indicates the change in the morphology caused due to etch pit opening on the surface.
