Linking nm-scale measurements of the anisotropy of silicate surface reactivity to macroscopic dissolution rate laws: New insights based on diopside

Daval, Damien; Hellmann, Roland; Saldi, Giuseppe D.; Wirth, Richard; Knauss, Kevin G.

doi:10.1016/j.gca.2012.12.045

Cited by 97 publications

(108 citation statements)

References 51 publications

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“…[5]). Both microscopes afford direct observation of mineral surfaces, and in situ AFM [6][7][8][9][10][11][12] and VSI [1,[13][14][15][16][17] have greatly expanded the understanding of reaction kinetics for a diverse range of carbonates, silicates, and other important phases. Calcite has been a favorite AFM and VSI target, due to its clear importance in environmental systems, its simple composition, and perfect cleavage.…”

Section: Introductionmentioning

confidence: 99%

Temporal Evolution of Calcite Surface Dissolution Kinetics

et al. 2018

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Abstract:This brief paper presents a rare dataset: a set of quantitative, topographic measurements of a dissolving calcite crystal over a relatively large and fixed field of view (~400 µm 2 ) and long total reaction time (> 6 h). Using a vertical scanning interferometer and patented fluid flow cell, surface height maps of a dissolving calcite crystal were produced by periodically and repetitively removing reactant fluid, rapidly acquiring a height dataset, and returning the sample to a wetted, reacting state. These reaction-measurement cycles were accomplished without changing the crystal surface position relative to the instrument's optic axis, with an approximate frequency of one data acquisition per six minutes' reaction (~10/h). In the standard fashion, computed differences in surface height over time yield a detailed velocity map of the retreating surface as a function of time. This dataset thus constitutes a near-continuous record of reaction, and can be used to both understand the relationship between changes in the overall dissolution rate of the surface and the morphology of the surface itself, particularly the relationship of (a) large, persistent features (e.g., etch pits related to screw dislocations; (b) small, short-lived features (e.g., so-called pancake pits probably related to point defects); (c) complex features that reflect organization on a large scale over a long period of time (i.e., coalescent "super" steps), to surface normal retreat and step wave formation. Although roughly similar in frequency of observation to an in situ atomic force microscopy (AFM) fluid cell, this vertical scanning interferometry (VSI) method reveals details of the interaction of surface features over a significantly larger scale, yielding insight into the role of various components in terms of their contribution to the cumulative dissolution rate as a function of space and time.

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Section: Introductionmentioning

confidence: 99%

Temporal Evolution of Calcite Surface Dissolution Kinetics

et al. 2018

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“…This includes studies on chemical and biochemical weathering (e.g. Hellmann et al 2012;Daval et al 2013;Bray 2014), archaeological findings damage (e.g. Rodriguez-Navarro and Benning 2013) or during mineral replacement (e.g.…”

Section: Introductionmentioning

confidence: 99%

Pressure solution in rocks: focused ion beam/transmission electron microscopy study on orthogneiss from South Armorican Shear Zone, France

Bukovská

Wirth

Morales

2015

Contrib Mineral Petrol

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In order to characterize the µm-to-nm structures related to operation of pressure solution on phase boundaries in naturally deformed rocks, we have performed a detailed focused ion beam/transmission electron microscopy study in ultramylonite samples from South Armorican Shear Zone (France) that focused on grain boundary scale. We have studied phase boundaries between quartz, K-feldspar and white mica both in 2 and 3D and compare our evidences with theoretical dissolution-precipitation models in the current literature. The dissolution (re)precipitation processes lead to the development of different features at different phase boundaries. In both quartz-white mica and quartz-K-feldspar phase boundaries, voids were ubiquitously observed. These voids have different shapes and the development of some of them is crystallographically controlled. In addition, part of these voids might be filled with vermiculite.Amorphous leached layers with kaolinite composition were observed at the boundaries of Kfeldspar-quartz and K-feldspar-white mica. The development of different features along the phase boundaries is mainly controlled by the crystallography of the phases sharing a common interface, together with the presence of fluids that either leaches or directly dissolve the mineral phases. In addition, the local dislocation density in quartz may play an important role during pressure solution.We suggest that the nano-scale observations of the quartz -white mica phase boundaries show direct evidence for operation of island-and-channel model as described in Wassmann and Stöckhert (2013), while K-feldspar -quartz phase boundaries represents amorphous layers formed via interface-coupled dissolution-reprecipitation as described by Hellmann et al. (2012).

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“…Experimentally and analytically, fundamental information about the evolution of reacting surface topographies and their heterogeneity have been gained by using surface-sensitive techniques such as atomic force microscopy, interferometry microscopy, or spectroscopy techniques (e.g., [1][2][3]). Measured reaction rates in laboratory experiments differ significantly under otherwise identical chemical conditions, often up to two to three orders of magnitude (e.g., [4,5]), indicating intrinsic differences in crystal surface reactivity [6]. As yet, a consistent theoretical model based on a purely mechanistic understanding of the heterogeneous distribution of surface reactivity is unavailable, despite its critical importance in understanding processes of, e.g., mineral conversion [7] or the pore evolution in geological structures [8].…”

Section: Introductionmentioning

confidence: 99%

Crystal Dissolution Kinetics Studied by a Combination of Monte Carlo and Voronoi Methods

2018

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Kinetic Monte Carlo (kMC) methods have been used extensively for the study of crystal dissolution kinetics and surface reactivity. A current restriction of kMC simulation calculations is their limitation in spatial system size. Here, we explore a new and very fast method for the calculation of the reaction kinetics of a dissolving crystal, capable of being used for much larger systems. This method includes a geometrical approach, the Voronoi distance map, to generate the surface morphology, including etch pit evolution, and calculation of reaction rate maps and rate spectra in an efficient way, at a calculation time that was about 1/180 of the time required for a kMC simulation of the same system size at one million removed atoms. We calculate Voronoi distance maps that are based on a distance metric corresponding to the crystal lattice, weighted additively in relation to stochastic etch pit depths. We also show how Voronoi distance maps can be effectively parameterized by kMC simulation results. The resulting temporal sequences of Voronoi maps provide kinetic information. By comparing temporal sequences of kMC simulation and Voronoi distance maps of identical etch pit distributions, we demonstrate the opportunity of making specific predictions about the dissolution reaction kinetics, based on rate maps and rate spectra. The dissolution of an initially flat Kossel crystal surface served as an example to show that a sequence of Voronoi calculations can predict dissolution kinetics based on the information about the distribution of screw defects. The results confirm that a geometrical relationship exists between the material flux from the surface at a certain point and the distance (or, when considering anisotropy, a function of distance) to the nearest defect. In this study, for the sake of comparability, the calculations are made using input parameters directly derived from the kMC models operating at the atomic scale. We show that, using values of v(r pit ) and weighting factors obtained by kMC, the resulting surface morphologies and material flux are almost identical. This implies that discrete Voronoi calculations of starting and end points of the dissolution are sufficient to calculate material flux maps, without the time-consuming overhead of computing the interim reactions at the atomic-scale. This opens a promising new venue to efficiently upscale full-atomic kMC models to the continuum macroscopic level where reactive transport and Lattice Boltzmann calculations can be applied.

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Linking nm-scale measurements of the anisotropy of silicate surface reactivity to macroscopic dissolution rate laws: New insights based on diopside

Cited by 97 publications

References 51 publications

Temporal Evolution of Calcite Surface Dissolution Kinetics

Temporal Evolution of Calcite Surface Dissolution Kinetics

Pressure solution in rocks: focused ion beam/transmission electron microscopy study on orthogneiss from South Armorican Shear Zone, France

Crystal Dissolution Kinetics Studied by a Combination of Monte Carlo and Voronoi Methods

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