Mechanism of leached layer formation during chemical weathering of silicate minerals
The dissolution of most common multicomponent silicate minerals and glasses is typically incongruent, as shown by the nonstoichiometric release of the solid phase components. This results in the formation of so-called surface leached layers. Due to the important effects these leached layers may have...
| Main Authors: | , , , |
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| Format: | Journal Article |
| Published: |
2012
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| Online Access: | http://hdl.handle.net/20.500.11937/10577 |
| _version_ | 1848747571426623488 |
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| author | Ruiz-Agudo, E. Putnis, Christine Rodriguez-Navarro, C. Putnis, Andrew |
| author_facet | Ruiz-Agudo, E. Putnis, Christine Rodriguez-Navarro, C. Putnis, Andrew |
| author_sort | Ruiz-Agudo, E. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The dissolution of most common multicomponent silicate minerals and glasses is typically incongruent, as shown by the nonstoichiometric release of the solid phase components. This results in the formation of so-called surface leached layers. Due to the important effects these leached layers may have on mineral dissolution rates and secondary mineral formation, they have attracted a great deal of research. However, the mechanism of leached layer formation is a matter of vigorous debate. Here we report on an in situ atomic force microscopy (AFM) study of the dissolution of wollastonite, CaSiO 3, as an example of leached layer formation during dissolution. Our in situ AFM results provide, for the first time, clear direct experimental evidence that leached layers are formed in a tight interface-coupled two-step process: stoichiometric dissolution of the pristine mineral surfaces and subsequent precipitation of a secondary phase (most likely amorphous silica) from a supersaturated boundary layer of fluid in contact with the mineral surface. This occurs despite the fact that the bulk solution is undersaturated with respect to the secondary phase. Our results differ significantly from the concept of preferential leaching of cations, as postulated by most currently accepted incongruent dissolution models. This interface-coupled dissolution-precipitation model has important implications in understanding and evaluating dissolution kinetics of major rock-forming minerals. © 2012 Geological Society of America. |
| first_indexed | 2025-11-14T06:51:16Z |
| format | Journal Article |
| id | curtin-20.500.11937-10577 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T06:51:16Z |
| publishDate | 2012 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-105772017-09-13T14:56:20Z Mechanism of leached layer formation during chemical weathering of silicate minerals Ruiz-Agudo, E. Putnis, Christine Rodriguez-Navarro, C. Putnis, Andrew The dissolution of most common multicomponent silicate minerals and glasses is typically incongruent, as shown by the nonstoichiometric release of the solid phase components. This results in the formation of so-called surface leached layers. Due to the important effects these leached layers may have on mineral dissolution rates and secondary mineral formation, they have attracted a great deal of research. However, the mechanism of leached layer formation is a matter of vigorous debate. Here we report on an in situ atomic force microscopy (AFM) study of the dissolution of wollastonite, CaSiO 3, as an example of leached layer formation during dissolution. Our in situ AFM results provide, for the first time, clear direct experimental evidence that leached layers are formed in a tight interface-coupled two-step process: stoichiometric dissolution of the pristine mineral surfaces and subsequent precipitation of a secondary phase (most likely amorphous silica) from a supersaturated boundary layer of fluid in contact with the mineral surface. This occurs despite the fact that the bulk solution is undersaturated with respect to the secondary phase. Our results differ significantly from the concept of preferential leaching of cations, as postulated by most currently accepted incongruent dissolution models. This interface-coupled dissolution-precipitation model has important implications in understanding and evaluating dissolution kinetics of major rock-forming minerals. © 2012 Geological Society of America. 2012 Journal Article http://hdl.handle.net/20.500.11937/10577 10.1130/G33339.1 restricted |
| spellingShingle | Ruiz-Agudo, E. Putnis, Christine Rodriguez-Navarro, C. Putnis, Andrew Mechanism of leached layer formation during chemical weathering of silicate minerals |
| title | Mechanism of leached layer formation during chemical weathering of silicate minerals |
| title_full | Mechanism of leached layer formation during chemical weathering of silicate minerals |
| title_fullStr | Mechanism of leached layer formation during chemical weathering of silicate minerals |
| title_full_unstemmed | Mechanism of leached layer formation during chemical weathering of silicate minerals |
| title_short | Mechanism of leached layer formation during chemical weathering of silicate minerals |
| title_sort | mechanism of leached layer formation during chemical weathering of silicate minerals |
| url | http://hdl.handle.net/20.500.11937/10577 |