Direct Observations of the Coupling between Quartz Dissolution and Mg-Silicate Formation
- Lisa de Ruiter (6452084)
- Christine V. Putnis (1445740)
- Jörn Hövelmann (1625197)
- Helen E. King (1445746)
- Håkon Austrheim (6452087)
DOIAbstract
Although quartz is a stable mineral at Earth surface conditions, field samples have shown its rapid dissolution in combination with the precipitation of Mg-silicate phases. Atomic force microscopy (AFM) experiments were performed to investigate the dissolution of quartz and the precipitation of secondary phases in high-pH, Mg-rich solutions both in situ and ex situ. Experiments were conducted at room temperature with varying MgCl2 or MgSO4 concentrations (0.1–100 mM), pH (8.9–12) and ionic strength (<1–530 mM). The results suggest that quartz dissolves by the removal of nanoparticles on the time scale of minutes, and that a nanometer-scale gel-like layer of amorphous silica forms on the quartz surface and is thicker at higher pH. During the...
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