Growth mechanisms, polytypism, and real structure of kaolinite microcrystals

Samotoin, N. D.

doi:10.1134/s1063774508050271

Cited by 4 publications

(9 citation statements)

References 4 publications

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“…12,17,28 Under hydrothermal conditions, layered silicates could grow through layer growth or spiral growth mechanisms. 12,13,17 The AFM images showed that the a−b planes were flat and lacked growth spirals (Figure 4), also consistent with the characteristic of the layer growth mechanism rather than that of the spiral growth mechanism. As mentioned above, the layer growth of minerals generally takes place under the conditions of a high oversaturation degree and temperature.…”

Section: Growth Mechanisms Of 2:1 Type Las During Mineral Transformationsupporting

confidence: 68%

“…These growth mechanisms well revealed the formation of polytypisms, crystal defects, and micromorphologies of layered silicates. 13,17 Generally, layer growth takes place under the conditions of a high oversaturation degree and temperature, 12,13 and it causes a significantly increased thickness of layered silicates. 15 By contrast, spiral growth appears in the relatively low oversaturation degree and temperature environments such as the conditions of the late stage of mineralization, 13,15 and it generally retains growth spirals on the basal surfaces.…”

Section: Introductionmentioning

confidence: 99%

“…13,17 Generally, layer growth takes place under the conditions of a high oversaturation degree and temperature, 12,13 and it causes a significantly increased thickness of layered silicates. 15 By contrast, spiral growth appears in the relatively low oversaturation degree and temperature environments such as the conditions of the late stage of mineralization, 13,15 and it generally retains growth spirals on the basal surfaces. Ostwald ripening mainly involves the dissolution and crystallization of small and large crystal particles, respectively, and it generally happens in environments with active water− rock interactions.…”

Section: Introductionmentioning

confidence: 99%

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Multiple Growth Mechanisms of 2:1 Type Layered Aluminosilicates during Mineral Transformation

et al. 2022

ACS Earth Space Chem.

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2:1 type layered aluminosilicates (LAs) such as beidellite, montmorillonite, and paragonite distribute widely in the various environments of the Earth, and they form commonly through the transformation of other minerals under hydrothermal or weathering conditions. Understanding the growth mechanisms of 2:1 type LAs during mineral transformation is of great importance for profoundly revealing their formation processes in the geological environments and a better understanding of the formation of crystal defects within minerals, however, which is not thoroughly revealed. In this study, the transformation of boehmite into 2:1 type LAs was successfully realized under hydrothermal conditions, and the growth mechanisms of 2:1 type LAs during such a mineral transformation were explored using spectroscopic and microscopic characterizations. The results indicated that layers of 2:1 type LAs preferentially extend in the a–b plane at the initial transformation stage and stack along the c-axis with the transformation proceeding. Additionally, some small primary nanoparticles of 2:1 type LAs occasionally attached to each other along the c-axis or in the a–b plane. This revealed that 2:1 type LAs that formed at the interfaces between precursor boehmite and additional amorphous Si mainly grew through the layer growth mechanism occasionally accompanied by the oriented attachment.

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Section: Growth Mechanisms Of 2:1 Type Las During Mineral Transformationsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Multiple Growth Mechanisms of 2:1 Type Layered Aluminosilicates during Mineral Transformation

et al. 2022

ACS Earth Space Chem.

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“…As was shown by Samotoin (2008) and in this paper, the relaxation of internal stresses in kaolinite microcrystals is implemented by local ruptures and slips of 7 Å layers along c axis for one or several periods, i.e., by arising screw dislocations with different Burg ers vectors rather than by twinning. As concerns the formation of regular kaolinite intergrowths (Mansfield and Bailey, 1972), this phenomenon is determined only by epitactic stage of their growth on primary min erals rather than by internal stresses in the structure.…”

Section: Epitactic and Autoepitactic Stages Of Kaolinite Growthmentioning

confidence: 94%

“…Their appearance is determined by internal stresses in this layer because of inconsistence of tetrahedral and octa hedral grids (Samotoin, 2008). The coupled (+ and -) screw dislocations connected by a joint step are formed in this case.…”

Section: Msmentioning

confidence: 98%

Formation of kaolinite nano- and microcrystals by weathering of phyllosilicates

Samotoin

Бортников

2011

Geol. Ore Deposits

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The relationship between morphology, size, and real structure of kaolinite microcrystals and the structure and composition of the primary minerals, by the weathering of which kaolinite is formed, was stud ied with analytical transmitted electron microscopy (ATEM), including vacuum decoration with gold, imag ing in transmitted light, selected area electron diffraction (SAED), and energy dispersive X ray spectroscopy (EDS). Muscovite, biotite, and chlorite that have been weathered (replaced with kaolinite) to varying degrees were examined. It has been shown that kaolinite is formed from the solution, which arises owing to decom position of primary minerals, and crystallizes immediately at the surface of these minerals without participa tion of any intermediate amorphous or crystalline phases. Kaolinite grows over primary minerals by mecha nism of periodical 2D nucleation at the early stage of its formation and by helical mechanism at the late stage. The difference in morphology, dimensions, and real structure of the kaolinite replacing muscovite, biotite, and chlorite is determined by various degrees of similarity with primary minerals in parameters and structural motifs, distinct strains of kaolinite structure at the stages of epitactic and autoepitactic growth, different resis tance of primary minerals to weathering and variable intensity of this process.

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Growth surface topography of kaolinite-group minerals and their simulation based on the regular sequence of enantiomorphic layers

Samotoin

Бортников

2014

Crystallogr. Rep.

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Growth mechanisms, polytypism, and real structure of kaolinite microcrystals

Cited by 4 publications

References 4 publications

Multiple Growth Mechanisms of 2:1 Type Layered Aluminosilicates during Mineral Transformation

Multiple Growth Mechanisms of 2:1 Type Layered Aluminosilicates during Mineral Transformation

Formation of kaolinite nano- and microcrystals by weathering of phyllosilicates

Growth surface topography of kaolinite-group minerals and their simulation based on the regular sequence of enantiomorphic layers

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