scholarly journals Kaolinite-to-Chlorite Conversion from Si,Al-Rich Fluid-Origin Veins/Fe-Rich Carboniferous Shale Interaction

Minerals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 804
Author(s):  
Franck Bourdelle ◽  
Michel Dubois ◽  
Emily Lloret ◽  
Cyril Durand ◽  
Ahmed Addad ◽  
...  
Keyword(s):  
Solid State ◽  
Low Temperature ◽  
Intermediate Phase ◽  
Hydrothermal Systems ◽  
Small Scale ◽  
State Transformation ◽  
Solid State Transformation ◽  
The North ◽  
Reducing Conditions ◽  
Carboniferous Shale

The kaolinite-to-chlorite conversion is one of the chloritization processes that occurs in low temperature diagenetic and hydrothermal systems. The mechanism of this mineralogical transformation is still under discussion, since direct transformation, conversion via berthierine as intermediate phase or direct formation of berthierine/chlorite mix, either by dissolution-crystallization or by solid state transformation (or a combination of both), are all hypotheses put forward. In this context, each description of a kaolinite-to-chlorite conversion occurrence becomes an opportunity to shed new light and to renew this debate. Studying Carboniferous shale–crosscut by large quartz-kaolinite veins–from the mining basin of the North of France, we report therefore an uncommon kaolinite-Fe-rich chlorite assemblage. This assemblage appears as a chlorite fringe 20 µm wide along the interfaces between the shale and the quartz-kaolinite veins. All petrographical, mineralogical and chemical data suggest that the Fe-chlorite results from the interaction between the shale, providing the Fe,Mg supply, and the Si,Al-rich veins, leading to the chloritization of the kaolinite at a small scale via at least one dissolution-recrystallisation step. High-resolution observations highlight that neoformed Fe-rich chlorite contains some 7Å isochemical layers, as relict of berthierine. Therefore, we advance that the conversion takes place either through the precipitation of berthierine following by a second step involving solid state berthierine-chlorite conversion, or through the direct precipitation of a chlorite-rich/berthierine-poor mix driven by the Fe/(Fe + Mg) ratio, at low temperature and in reducing conditions. The comparison of our data with the recent literature allows to prefer the second hypothesis.

Preparing Bi12SiO20 crystals at low temperature through nontopotactic solid-state transformation and improving its photocatalytic activity by etching

2015 ◽  
Vol 3 (14) ◽  
pp. 7413-7421 ◽  
Author(s):  
Qiaofeng Han ◽  
Juan Zhang ◽  
Xin Wang ◽  
Junwu Zhu
Keyword(s):  
Photocatalytic Activity ◽  
Solid State ◽  
Low Temperature ◽  
Visible Light ◽  
State Transformation ◽  
Solid State Transformation ◽  
Visible Light Photocatalytic Activity ◽  
Visible Light Photocatalytic

The egg-tart shaped BiOCl hierarchitectures with efficient visible-light photocatalytic activity were prepared through etching of Bi12SiO20 obtained at low temperature.

Clay crystal-chemical adaptability and transformation mechanisms

Clay Minerals ◽  
2012 ◽  
Vol 47 (2) ◽  
pp. 147-164 ◽  
Author(s):  
J. Cuadros
Keyword(s):  
Solid State ◽  
Reaction Mechanisms ◽  
Morphological Changes ◽  
Atomic Scale ◽  
Small Scale ◽  
Minor Role ◽  
Crystal Chemical ◽  
State Transformation ◽  
Solid State Transformation ◽  
A Minor

AbstractChemical and mineralogical transformations of phyllosilicates are among the most important in diagenetic environments in all types of rocks because they can exert a large control on the processes taking place in such environments and/or provide constraints for the conditions in which phyllosilicate transformation occurred. Dissolution-precipitation and solid-state transformation are usually the two mechanisms proposed for such reactions depending on the crystal-chemical and morphological similarities between parent and neoformed phases together with knowledge of the environmental conditions. These two mechanisms, however, may be at both ends of the spectrum of those operating and many transformations may take place through a mixture of the two mechanisms, generating observable elements that are characteristic of one or the other. In the present literature, the boundaries between the two mechanisms are not clear, mainly because dissolution-precipitation is sometimes defined at nearly atomic scale. It is proposed here that such small-scale processes are considered as a solid-state transformation, and that dissolution-precipitation requires dissolution of entire mineral particles and their dissolved species to pass into the bulk of the solution. Understanding the reaction mechanisms of diagenetic transformations is an important issue because they impinge on geochemical conditions and variables such as cation mobility, rock volume, fabric changes, rock permeability, stable isotope signature and phyllosilicate crystal-chemistry.I propose that, in the lower range temperatures at which clay mineral transformations take place, energy considerations favour solid-state transformation, or reactions that involve the breaking of a limited number of bonds, over dissolution of entire grains and precipitation of crystals of the new phase. Large morphological changes are frequently invoked as evidence for a dissolution-precipitation mechanism but changes in particle shape and size may be achieved by particle rupture, particle welding or by hybrid processes in which dissolution-precipitation plays a minor role.Past and recent studies of phyllosilicate transformations show chemical and structural intermediates indicating a large crystal-chemical versatility, greater than is commonly recognized. These intermediates include tetrahedral sheets of different composition within TOT units (termed polar layers), dioctahedral and trioctahedral domains in the same layer, and 2:1 and 1:1 domains also within the same layers. The existence of such intermediate structures suggests that the reaction mechanisms that generated them are within the realm of the solid-state transformation processes.

Solid-state Transformation of Achiral Crystals to a Chiral Crystal by Guest Release from Host–Guest Inclusion Crystals of Achiral Host Compound

2009 ◽  
Vol 38 (11) ◽  
pp. 1080-1081 ◽  
Author(s):  
Hironori Saito ◽  
Mitsuaki Suzuki ◽  
Hiroshi Miyamae ◽  
Naoto Hayashi ◽  
Keiji Kobayashi
Keyword(s):  
Solid State ◽  
State Transformation ◽  
Solid State Transformation ◽  
Host Compound

scholarly journals Maskelynite formation via solid-state transformation: Evidence of infrared and X-ray anisotropy

2015 ◽  
Vol 120 (3) ◽  
pp. 570-587 ◽  
Author(s):  
Steven J. Jaret ◽  
William R. Woerner ◽  
Brian L. Phillips ◽  
Lars Ehm ◽  
Hanna Nekvasil ◽  
...  
Keyword(s):  
Solid State ◽  
State Transformation ◽  
Solid State Transformation ◽  
X Ray

Solid-State Reactions in Multilayer Ni/Ti Thin Film Composites

1990 ◽  
Vol 205 ◽  
Author(s):  
Gillian E. Winters ◽  
K.M. Unruh ◽  
C.P. Swann ◽  
M.E. Patt ◽  
B.E. White ◽  
...  
Keyword(s):  
Solid State ◽  
Solid State Reactions ◽  
Metastable Solid Solution ◽  
State Transformation ◽  
Solid State Transformation ◽  
Scanning Calorimetry ◽  
The Individual ◽  
Thin Film Composites ◽  
Film Composites ◽  
Rf Sputter Deposition

AbstractMultilayer films, consisting of alternating layers of crystalline Ni and Ti, have been prepared by RF sputter deposition over a range of modulation wavelengths corresponding to an overall composition of Ni50Ti50. These films have been characterized by xray diffraction and Rutherford backscattering measurements. The solid-state transformation by interdiffusional mixing of the individual layers has been directly studied by differential scanning calorimetry and correlated with structural measurements. These measurements indicate that the solid-state reaction of Ni and Ti multilayers proceeds through the formation of a metastable solid solution of Ti in Ni followed by the formation of intermetallic equilibrium compounds. No direct calorimetric or structural evidence for the formation of an amorphous Ni-Ti phase has been found in these samples.

Self-assembled ZnO-rGO nanocomposite, a solid-state transformation to control its crystallite size

2021 ◽  
pp. 159992
Author(s):  
Germán Pérez-Zúñiga ◽  
Gabriel Herrera-Pérez ◽  
Ysmael Verde-Gómez ◽  
Ana María Valenzuela-Muñiz
Keyword(s):  
Solid State ◽  
Crystallite Size ◽  
State Transformation ◽  
Solid State Transformation ◽  
Self Assembled
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