• journal_title：American Mineralogist
• Contributor：Yun Liu ; Amanda A. Olsen ; J. Donald Rimstidt
• Publisher：Mineralogical Society of America
• Date：2006-
• Format：text/html
• Language：en
• Identifier：10.2138/am.2006.2077
• journal_abbrev：American Mineralogist
• issn：0003-004X
• volume：91
• issue：2-3
• firstpage：455
• section：Letters

The complexity of silicate minerals makes prediction of their dissolution rates a challenging problem. A combination of large cluster ab-initio quantum mechanical models and chemical probe dissolution experiments are used to understand the dissolution process for olivine-group minerals. Rapid release of M²⁺ cations by precursor reactions involving H⁺ attack at μ₃-O surface sites produces a silica-enriched surface. Slower rates of silica release via a ligand exchange reaction involving a proton in the activated complex controls the overall rate of olivine dissolution. Our results provide a physical explanation for the correlation among olivine dissolution rates and water exchange rates for the corresponding aqueous cation.