Extended Data Fig. 4: Gold solubility in our experiments vs. typical orogenic systems.
From: Gold nugget formation from earthquake-induced piezoelectricity in quartz
Eh vs. pH diagrams showing the potentials required to reduce aqueous gold. (a) Gold present as AuCl4− in our room-temperature experiments and (b) shown as the Au(HS)2- ± Au(HS)(aq) complexes typical in orogenic gold fluids, into metallic gold, as a function of gold in solution. The diagrams of iron also shown for comparison, where (c) and (d) correspond to (a) and (b), respectively. Abbreviations: Hem – hematite, Mgn – magnetite, Po- pyrrhotite, Py – pyrite. QMF in (d) shows the pH corresponding to quartz-muscovite-K-feldspar for activities of K+ of 0.1 to 0.01.
