Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations
We provide a detailed 3D characterization of the geometry evolution and dissolution rate mapping at the surface of four carbonate samples, namely a calcite spar crystal, two limestone rock fragments, and an aragonite ooid, using time-lapse X-ray micro-tomography during dissolution experiments at pH...
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| Language: | English |
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Frontiers Media S.A.
2023-06-01
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| Series: | Frontiers in Water |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/frwa.2023.1185608/full |
| _version_ | 1797800742199754752 |
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| author | Marthe Grønlie Guren François Renard François Renard Catherine Noiriel |
| author_facet | Marthe Grønlie Guren François Renard François Renard Catherine Noiriel |
| author_sort | Marthe Grønlie Guren |
| collection | DOAJ |
| description | We provide a detailed 3D characterization of the geometry evolution and dissolution rate mapping at the surface of four carbonate samples, namely a calcite spar crystal, two limestone rock fragments, and an aragonite ooid, using time-lapse X-ray micro-tomography during dissolution experiments at pH 4.0. Evaluation of the retreat and mapping of the reaction rates at the whole surface of the samples reveals a large spatial variability in the dissolution rates, reflecting the composition and the specific contributions of the different regions of the samples. While crystal edges and convex topographies record the highest dissolution rates, the retreat is slower for flat surfaces and in topographic lows (i.e., concave areas), suggesting surface-energy related and/or diffusion-limited reactions. Microcrystalline aragonite has the highest rate of dissolution compared to calcite. Surprisingly, rough microcrystalline calcite surface dissolves globally more slowly than the {101̄4} faces of the calcite spar crystal. The presence of mineral impurities in rocks, through the development of a rough interface that may affect the transport of species across the surface, may explain the slight decrease in reactivity with time. Finally, a macroscopic stochastic model using the set of detachment probabilities at corner, edge, and face (terrace) sites obtained from kinetic Monte Carlo simulations is applied at the spar crystal scale to account for the effect of site coordination onto reactivity. Application of the model to the three other carbonate samples is discussed regarding their geometry and composition. The results suggest that the global dissolution process of carbonate rocks does not reflect only the individual behavior of their forming minerals, but also the geometry of the crystals and the shape of the fluid-mineral interface. |
| first_indexed | 2024-03-13T04:38:50Z |
| format | Article |
| id | doaj.art-e9da034e8f344086b109803a63d8e267 |
| institution | Directory Open Access Journal |
| issn | 2624-9375 |
| language | English |
| last_indexed | 2024-03-13T04:38:50Z |
| publishDate | 2023-06-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Water |
| spelling | doaj.art-e9da034e8f344086b109803a63d8e2672023-06-19T06:32:55ZengFrontiers Media S.A.Frontiers in Water2624-93752023-06-01510.3389/frwa.2023.11856081185608Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigationsMarthe Grønlie Guren0François Renard1François Renard2Catherine Noiriel3Departments of Geosciences and Physics, The Njord Centre, University of Oslo, Oslo, NorwayDepartments of Geosciences and Physics, The Njord Centre, University of Oslo, Oslo, NorwayISTerre, University Grenoble Alpes, University Savoie Mont Blanc, University Gustave Eiffel, CNRS, IRD, Grenoble, FranceGéosciences Environnement Toulouse, Observatoire Midi-Pyrénées, Université Paul Sabatier, CNRS, IRD, CNES, Université de Toulouse, Toulouse, FranceWe provide a detailed 3D characterization of the geometry evolution and dissolution rate mapping at the surface of four carbonate samples, namely a calcite spar crystal, two limestone rock fragments, and an aragonite ooid, using time-lapse X-ray micro-tomography during dissolution experiments at pH 4.0. Evaluation of the retreat and mapping of the reaction rates at the whole surface of the samples reveals a large spatial variability in the dissolution rates, reflecting the composition and the specific contributions of the different regions of the samples. While crystal edges and convex topographies record the highest dissolution rates, the retreat is slower for flat surfaces and in topographic lows (i.e., concave areas), suggesting surface-energy related and/or diffusion-limited reactions. Microcrystalline aragonite has the highest rate of dissolution compared to calcite. Surprisingly, rough microcrystalline calcite surface dissolves globally more slowly than the {101̄4} faces of the calcite spar crystal. The presence of mineral impurities in rocks, through the development of a rough interface that may affect the transport of species across the surface, may explain the slight decrease in reactivity with time. Finally, a macroscopic stochastic model using the set of detachment probabilities at corner, edge, and face (terrace) sites obtained from kinetic Monte Carlo simulations is applied at the spar crystal scale to account for the effect of site coordination onto reactivity. Application of the model to the three other carbonate samples is discussed regarding their geometry and composition. The results suggest that the global dissolution process of carbonate rocks does not reflect only the individual behavior of their forming minerals, but also the geometry of the crystals and the shape of the fluid-mineral interface.https://www.frontiersin.org/articles/10.3389/frwa.2023.1185608/fullcarbonate dissolutionX-ray micro-tomographydissolution rate distributionrate mappingstochastic modeling |
| spellingShingle | Marthe Grønlie Guren François Renard François Renard Catherine Noiriel Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations Frontiers in Water carbonate dissolution X-ray micro-tomography dissolution rate distribution rate mapping stochastic modeling |
| title | Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations |
| title_full | Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations |
| title_fullStr | Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations |
| title_full_unstemmed | Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations |
| title_short | Dissolution rate variability at carbonate surfaces: 4D X-ray micro-tomography and stochastic modeling investigations |
| title_sort | dissolution rate variability at carbonate surfaces 4d x ray micro tomography and stochastic modeling investigations |
| topic | carbonate dissolution X-ray micro-tomography dissolution rate distribution rate mapping stochastic modeling |
| url | https://www.frontiersin.org/articles/10.3389/frwa.2023.1185608/full |
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