Calcite dissolution: Effects of trace cations naturally present in Iceland spar calcites

Harstad, Andreas Olaus; Stipp, S. L. S.

doi:10.1016/j.gca.2006.07.037

Cited by 79 publications

(85 citation statements)

References 44 publications

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“…The observed rounding of the obtuse-obtuse corners in Fig. 1 might be associated with trace impurities present in the system (Lea et al, 2001;Arvidson et al, 2003;Freij et al, 2005;Harstad and Stipp, 2007;Ruiz-Agudo et al, 2009). …”

Section: Resultsmentioning

confidence: 92%

Kinetics and mechanisms of cadmium carbonate heteroepitaxial growth at the calcite (101¯4) surface

Xu¹,

Kovařík²,

Arey³

et al. 2014

Geochimica et Cosmochimica Acta

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Elucidating the kinetics and mechanisms of heteroepitaxial nucleation and growth at mineral-water interfaces is essential to understanding surface reactivity in geochemical systems. In the present work, the formation of heteroepitaxial cadmium carbonate coatings at calcite-water interfaces was investigated by exposing calcite ð10 1 4Þ surfaces to Cd-bearing aqueous solutions. In situ atomic force microscopy (AFM) was employed as the primary technique. The AFM results indicate that the heteroepitaxial growth of cadmium carbonate proceeds via three different mechanisms depending on the initial supersaturation of the aqueous solution: advancement of existing steps, nucleation and growth of three-dimensional (3D) islands, and nucleation and spread of two-dimensional (2D) nuclei. The 3D islands and 2D nuclei exhibit different morphologies and growth kinetics. The effects of supersaturation on heteroepitaxial growth mechanisms can be interpreted in terms of the free energy barrier for nucleation. At low initial supersaturation, where 3D nucleation dominates, it is hypothesized, from the growth rate and morphology of the 3D islands observed with AFM, that the crystallization of the overgrowth follows a non-classical pathway involving the formation of a surface precursor that is not fully crystalline, whereas high supersaturation favors the formation of crystalline 2D nuclei whose morphology is based on the atomic structure of the calcite substrate. Cross-sectional transmission electron microscopy (TEM) images reveal that the atomic structure of the interface between the cadmium carbonate coating and calcite shows perfect, dislocation-free epitaxy.

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Section: Resultsmentioning

confidence: 92%

Kinetics and mechanisms of cadmium carbonate heteroepitaxial growth at the calcite (101¯4) surface

Xu¹,

Kovařík²,

Arey³

et al. 2014

Geochimica et Cosmochimica Acta

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“…Experimentally observed recrystallisation rates at high temperatures increased by an order of magnitude when in the presence of Mn-rich fluids (Olgaard, 1985). However, calcite dissolution experiments involving atomic force microscopy show that Mn-rich calcites resist dissolution relative to more pure calcites (Harstad and Stipp, 2007).…”

Section: Strain Localisation and Review Materials Strength Factorsmentioning

confidence: 99%

“…Mn has been observed to enhance diffusion creep by up to an order of magnitude (Freund et al, 2004) which is linked to enhanced grain boundary mobility (Olgaard, 1985;Freund et al, 2001). However, dissolution experiments have shown that Mn-rich calcites are more resistant to dissolution (Harstad and Stipp, 2007).…”

Section: C3 Cement Deformationmentioning

confidence: 99%

“…As the low-temperature D1 dissolution occurred in the coarse-ooid layer and preferentially dissolved the cement, the Mn-rich C3 cement was more resistant to dissolution (Harstad and Stipp, 2007) than the Mn-poor C1 and C2 were preferentially dissolved. Geometry also supports this as C1 and C2 were closer to the clay-rich dissolution zones within the ooids and must be dissolved prior to C3 reaching these dissolution zones.…”

Section: C3 Cement Deformationmentioning

confidence: 99%

“…However, these mechanisms do not contribute significantly to the finite strain in the C3 cement, and the dominant deformation mechanism observed is pressure solution. Mn-content is also known to slow dissolution by pressure solution (Harstad and Stipp, 2007). Therefore, it is unlikely that Mn content resulted in a layer viscosity variation and H2 is rejected.…”

Section: Summary Of Deformation Mechanismsmentioning

confidence: 99%

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Millimetre-Scale Localisation of Strain and Dissolution in Oolitic Grainstone

Lynch¹

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Millimetre-scale localisation of strain and dissolution in oolitic grainstone ii KeywordsCarbonate, clay dissolution, cement, CPO, ductile, deformation mechanisms, EBSD, grain boundary sliding, geological history, initial interfaces, microfabric, ooid, oolite, porosity, pressure solution, SPO, strain localisation, stylolite, viscosity, XFMMillimetre-scale localisation of strain and dissolution in oolitic grainstone iii AbstractLocalisation of finite strain in rocks is commonly explained by variations in loading conditions, rock mechanical properties and rock fabric. In a geological sequence of layered rocks where loading conditions (such as temperature and far-field stress) are similar, strain variations are commonly constrained to layers with differing material properties. The examined Gudman Oolite presents a unique and interesting example of how variable finite strain is influenced by minor variations in material properties.The Carboniferous Gudman Oolite features alternating millimetre-to centimetre-thick layers of coarse ooids (mean diameter ~1-3mm) and fine ooids (mean diameter ~0.5-1mm) within a sparitic cement (30-300µm grains). Each layer is predominantly (>95%) calcite, formed in the same depositional environment and experienced the same tectonic history. However, the coarse-ooid layers show high non-coaxial deformation and extensive stylolite textures. In contrast, the fine-ooid layers appear nearly undeformed, and are almost devoid of dissolution textures.To shed light on the reasons for this marked localisation of deformation and dissolution, the rock mechanical properties and rock fabric were measured using a combination of X-ray Fluorescence Microscopy (XFM), Electron Backscatter Diffraction (EBSD), X-ray Diffraction (XRD), palaeotemperature analysis and petrographic methods including Scanning Electron Microscopy (SEM), Cathodoluminescence (CL) and transmitted light microscopy. Examination of overprinting relationships in the coarse-ooid layer shows that localised dissolution (D1) occurred prior to localised non-coaxial strain (D2). Primitive stylolite textures suggest that dissolution seams formed in concentric mica-rich layers within ooids which occasionally linked to surrounding ooids to form laterally extensive stylolite seams. I argue that the relatively larger ooids in the coarse-ooid layer contain more extensive micaceous layers which promoted linking and dissolution to form laterally continuous stylolite seams.I conclude that D1 dissolution destroyed the C3 cement framework and reduced the strength of the coarse-ooid layer relative to the largely preserved fine-ooid layer. The later D2 shear deformation event localised strain in the weakened coarse-ooid layer.

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