Stacking Faults in Kaolin-Group Minerals in the Light of Real Structural Features

Bookin, A. S.; Drits, Victor A.; Plançon, A.; Tchoubar, C.

doi:10.1346/ccmn.1989.0370402

Cited by 96 publications

(54 citation statements)

References 21 publications

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“…In addition, one kaolinite, from Charentes, of a type not represented in the Brindley et al collection, was examined. The defect model used was that described by Bookin et aL (1989), and the goal of the present study was to reproduce the entire X-ray diffraction profile, including interpeak background as well as peak heights and shapes.…”

Section: Clays and Clay Mineralsmentioning

confidence: 99%

“…The model proposed by Plan~on and Tchoubar (1977), while generally considered to be the best model of the defect structure of kaolinite, is not completely satisfactory because of (1) crystal chemical arguments, and (2) the fact that some features of the observed XRD profiles are not accurately reproduced by the model. As pointed out by Bookin et al (1989), some of the defects introduced by Planqon and Tchoubar have a high energy (distortions of the layers, unfavorable stacking sequence, etc.) and therefore are unlikely in the low-energy environments where kaolinite typically forms.…”

mentioning

confidence: 99%

“…and therefore are unlikely in the low-energy environments where kaolinite typically forms. To remedy this weakness, Bookin et aL (1989) proposed that the defects in kaolinite arise from (1) the coexistence in crystals of structural fragments (B layers only) of right-and left-handed kaolinite each generated by different interlayer vectors; and (2) the presence of some C layers in a predominantly B-layer structure.…”

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confidence: 99%

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Stacking Faults in the Kaolin-Group Minerals: Defect Structures of Kaolinite

Plançon

Giese

Snyder

et al. 1989

Clays and clay miner.

117

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Abstract-Previous studies of the defect structure of kaolinite have examined samples having a restricted level of defects. This study examined nine kaolinite samples having a large diversity of defect contents, as indicated by Hincldey indexes ranging from 1.44 to 0.18. The samples were chosen so as to cover this range in as regular a manner as possible. The types and abundances of the defects were determined by examining the X-ray powder diffraction profiles for the 02,11 and 20,13 bands. The diffraction intensities were measured by counting for a fixed time in steps of 0.01"20. Analysis of these diffraction profiles indicatedthat (1) the major defect is the existence of a translation between adjacent layers, which is not the usual tl (approximately a/3), but is related to that translation by the pseudo-mirror plane coincident with the long diagonal of the unit cell; (2) the existence of a few C layers among the B layer stacking is a minor defect; (3) many of the samples could be accurately modeled only by assuming the existence of two kaolinite phases; (4) the existence of only a few C layers in some samples does not support the idea of a continuous series from kaolinite to dickite through disordered intermediates; and (5) the Hinckley indexes of several samples depend on the relative proportions of the two types of kaolinite in the mixture.The nine kaolinite samples fall into three groups: those having a low to moderate abundance of defects (Hinckley index > 0.43) are mixtures of two types of kaolinite (one almost free of defects, the other richer in defects); those having low Hinckley indexes (0.43 to 0.18) are single phases with different proportions of defects; and those which contain a single type of kaolinite, unlike the others in the nature of the interlayer translations and the greater abundance of C layers. The agreement between calculated and observed X-ray diffraction profiles is excellent for all specimens, except one sample (from Charentes) for which the fit is acceptable but not perfect.

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Section: Clays and Clay Mineralsmentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

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Stacking Faults in the Kaolin-Group Minerals: Defect Structures of Kaolinite

Plançon

Giese

Snyder

et al. 1989

Clays and clay miner.

117

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“…Because polytype theory is based on ideal structures, the real structural details of individual minerals must be understood as suggested by Bookin et al (1989). These details, including tetrahedral rotations, polyhedral distortions, defects and disorder, can be studied through careful X-ray diffraction studies (Reynolds, 1989;Drits and Tchoubar, 1990), as well as with transmission electron microscopy (TEM) and selected-area electron diffraction (Veblen, 1985).…”

Section: Discussionmentioning

confidence: 99%

Chlorite Polytype Geothermometry

Walker

1993

Clays and clay miner.

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Abstract--Since the initial studies of chlorite polytypes, it has been suggested that the stability of the various polytypes may be a function of the temperature at which the mineral formed; however, few studies have been performed in which polytypes of chlorite in a specific suite of samples have been determined and correlated with temperature. A review of the reported occurrences of type I chlorite indicates that other factors, including grain size of the host rock, may be at least as important as temperature in controlling the stability of these polytypes. Results of systematic studies in areas of diagenesis and very low-grade metamorphism suggest that type-It chlorite is stable at temperatures well below 200~ and that it can form as the initial chlorite phase without passing through any intermediate polytypic stages. The conditions under which type-I polytypes occur are somewhat restricted, and cognizance of those restrictions will help to direct future studies of chlorite polytype transformations. These studies should focus on the structural details of polytype transformations; on the relationship of polytype stability to pressure, composition and kinetics; and on experimental calibration of the transformations.

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“…Particle shape of kaolinite is regular and pseudohexagonal. One of substantial parameters affecting the utilization of kaolins is the "crystallinity" or degree of structural ordering of kaolinite (Plançon & Tchoubar 1977a,b;Plançon et al 1988Plançon et al , 1989Bookin et al 1989). The level of kaolinite ordering is usually expressed by indices calculated from their X-ray diffraction patterns (Hinckley 1963;Plançon & Zacharie 1990;Aparicio et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Stability of kaolin sand from the Vyšný Petrovec deposit (south Slovakia) in an acid environment

Pentrák¹,

Madejová²,

Slávka³

et al. 2012

Geologica Carpathica

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Abstract:Comprehensive characterization of kaolin sand from the Vyšný Petrovec (VP) deposit in Slovakia by a variety of experimental methods was performed. The quantitative XRD analysis (RockJock software) revealed that the acid-untreated sample contained mainly kaolinite (~60 wt. %), a considerable amount of dioctahedral micas (~32 wt. %) and quartz (~7 wt. %). The Hinckley index (HI) and Aparicio-Galán-Ferrel index (AGFI) calculated from the 02l and 11l reflections showed medium-defect kaolinite to be present in the VP kaolin. The influence of the mineral composition of VP kaolin on its stability in 6 mol · dm -3 HCl at 95 °C was investigated. The solid reaction products were examined by chemical analysis; XRD and infrared spectroscopy in both middle (MIR) and near (NIR) regions. Considerably higher dissolution rate of Fe compared to Al indicated that Fe was bounded in a readily soluble phase rather than in kaolinite. While the MIR spectra confirmed the gradual release of the central atoms from the clay minerals layers and creation of amorphous silica upon acid treatment, the NIR spectra revealed the formation of Si-OH groups in the solid reaction product. Relatively high dissolution rate of VP kaolin resulted from the presence of small-grains of mediumdefect kaolinite and clay admixtures in VP kaolin sand.

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Stacking Faults in Kaolin-Group Minerals in the Light of Real Structural Features

Cited by 96 publications

References 21 publications

Stacking Faults in the Kaolin-Group Minerals: Defect Structures of Kaolinite

Stacking Faults in the Kaolin-Group Minerals: Defect Structures of Kaolinite

Chlorite Polytype Geothermometry

Stability of kaolin sand from the Vyšný Petrovec deposit (south Slovakia) in an acid environment

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