Surface specific measurements of olivine dissolution by phase-shift interferometry

摘要: Natural olivine dissolution and replacement often occurs preferentially along specific crystallographic planes. Thus, reactivity at surfaces was examined in situ using phase-shift interferometry, which has a detection limit <10−5 nm/s, by dissolving two smoothed crystal faces third sample corresponding to surface that generated preferential structural defects. The experiments were conducted 22 °C ambient pressure 0.1 M NaCl solutions acidified pHs between 1 4 HCl. These show can vary from one another as well different areas of the same have similar characteristics. fastest vertical retreat occurred related However, only advancement observed pH on this consistent with observation isolated islands during atomic force microscopy investigations after experiment. Raman analysis precipitated phase showed it not thermodynamically stable phases expected PHREEQC modeling. correlation siloxane ring peak amorphous silica precipitate spectrum, conjunction previous experimental natural observations, indicates Si-enriched phase. Therefore, precipitation facilitate further long does completely armor surface. Precipitate formation associated outcropping defects supports observations serpentinization these implying fast will play critical role replacement. In addition, comparison flow-through outflow fluid chemistry may provide an incomplete picture processes occurring dissolution.