Clay Minerals in the MacAdams Sandstone, California: Implications for Substitution of H3O+ and H2O and Metastability of Illite

Jiang, Wei Teh; Peacor, Donald R.; Essene, Eric J.

doi:10.1346/ccmn.1994.0420105

Cited by 23 publications

(9 citation statements)

References 24 publications

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“…Such a difference in the formation of cavansite and pentagonite cannot be verified by comparing the crystallization temperatures of H 3 O + -bearing minerals such as jarosite -alunite groups (Ripmeester et al, 1986;Lager et al, 2001), hydrated uranates (Demartin et al, 1991;Chukanov et al, 1999;Chukanov et al, 2004), and clay min- Table 9. Assignment of hydrogens to the refined oxygens using the difference in bond -valence sum of cavansite Polymorphic relation between cavansite and pentagonite erals (Jiang et al, 1994). However, extensive search on hydrous materials containing H 3 O + has been carried out in the realm of materials science.…”

Section: Polymorphic Relation Between Cavansite and Pentagonitementioning

confidence: 99%

Polymorphic relation between cavansite and pentagonite: Genetic implications of oxonium ion in cavansite

Ishida

Kimata

Nishida

et al. 2009

Journal of Mineralogical and Petrological Sciences

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The chemical compositions of cavansite and pentagonite, in which H 2 O contents and vanadium (in an unknown oxidation state) are present, were determined by thermogravimetry -differential thermal analysis (TG -DTA), electron spin resonance (ESR), and electron microprobe analysis (EMPA). Furthermore, the mechanism of dehydration of the minerals and presence of the hydrous species such as H 2 O, H 3 O + , and OH − in the aforementioned minerals have been investigated by TG -DTA, high -temperature X -ray diffraction (HT -XRPD) analysis, Fourier -transform infrared (FTIR) spectroscopy, and single -crystal XRD analysis. The results of TG -DTA and HT -XRD revealed that no reversible transitions occur between cavansite and pentagonite when they are heated in air and that no intermediate amorphous phase exists in these two minerals. Gradual dehydration of cavansite in the temperature range of 225 -550 °C was attributed to the removal of both oxonium (H 3 O + ) and hydroxyl ions (OH − ); the IR absorption bands of cavansite observed at 3186 and 3653 cm −1 were assigned to H 3 O + and OH − stretching vibrations, respectively. Moreover, the exact distribution of hydrogens in the crystal structure of the cavansite refined in this study was determined by applying the valence -matching principle; the results showed the existence of H 3 O + and OH − . Thus, the structural formula of cavansite should be revised to Ca(VO)(Si 4 O 10 )·(H 2 O) 4−2x (H 3 O) x (OH) x , in contrast to that of pentagonite, Ca(VO)(Si 4 O 10 )·4H 2 O. The changes in the ion product constant of water with temperature and pressure suggest that pentagonite is formed when the hydrothermal fluid is in supercritical condition (>300 °C), while cavansite is formed when the hydrothermal fluid is not in supercritical condition. Thus, cavansite is identified as a low -temperature form and pentagonite as a high -temperature one.

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Section: Polymorphic Relation Between Cavansite and Pentagonitementioning

confidence: 99%

Polymorphic relation between cavansite and pentagonite: Genetic implications of oxonium ion in cavansite

Ishida

Kimata

Nishida

et al. 2009

Journal of Mineralogical and Petrological Sciences

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“…early (Crowley, 1991) and advanced diagenesis, (Marfil and Gomez Gras, 1992) and subsequent uplift (Jiang et al, 1994). For the intergrowth to be formed, muscovite must provide template sites for the nucleation and subsequent growth of authigenic kaolinite, while additional elements must be supplied by a parent material (muscovite and/or other minerals such as feldspars and other phyllosilicates).…”

Section: Introductionmentioning

confidence: 99%

Microtextures and the Origin of Muscovite-Kaolinite Intergrowths in Sandstones of the Utrillas Formation, Basque Cantabrian Basin, Spain

Aróstegui

Irabién

Nieto

et al. 2001

Clays and clay miner.

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Abstract--Muscovite-kaolinite intergrowths found in Albian sandstones of the Basque Cantabrian basin (northern Spain) were studied by optical, scanning and electron microscopy and electron microprobe analysis. Kaolinitization begins at grain edges, forming the characteristic fanned-out textures, and propagates toward the interior along the cleavages of muscovite. Kaolinite and muscovite occur as thick packets, being free of interlayering. Phase boundaries between both minerals show bidimensional crystallographic continuity, and no intermediate phases have been identified. The data obtained suggest that muscovite only supplied a template suitable for the epitactic crystallization of kaolinite, while A1 was available in sufficient amounts due to the dissolution of detrital K-feldspar. Very small packets of magnetite or maghemite showing a coherent orientation with the kaolinite crystals have been recognized, and could be responsible for the small Fe contents usually detected in electron microprobe analyses of kaolinite.Textural relationships between authigenic kaolinite and deformation microstructures in the intergrowths, combined with previous information about burial conditions, show that alteration proceeded during a late stage of the diagenetic history, related to the uplift of the studied materials as a result of the Alpine orogeny.

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“…Selected area electron diffraction (SAED) patterns were obtained with a camera length of 770 ram. EDS data were obtained in scanning mode over 300 • 300 ,~ areas and processed using k-factors as defined by Jiang et al (1994). AEM analyses were obtained only from grains which were first characterized by TEM techniques.…”

Section: Methodsmentioning

confidence: 99%

“…Smectite is considered to be a metastable phase by some authors (e.g., Jiang et al, 1994). It commonly forms from materials such as volcanic ash and then generally transforms to illite at low temperatures and in relatively young rocks in an Ostwald-step-rule, prograde sequence where the successive mineral assemblages are of decreasing free energy.…”

Section: Introductionmentioning

confidence: 99%

“Retrograde Diagenesis” of Clay Minerals in the Precambrian Freda Sandstone, Wisconsin

Zhao

Peacor

McDowell

1999

Clays and clay miner.

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Abstract--Siltstones from the Precambrian Freda Formation in Wisconsin have been studied by scanning, scanning-transmission and analytical electron microscopy (SEM, STEM and AEM), and X-ray diffraction (XRD). XRD data for drill core samples show a change from smectite-rich Illite-Smectite (I-S) in shallow samples to illite in deeper samples, implying a transition during burial diagenesis.Transmission electron microscopy (TEM) observations of shallow samples reveal the presence of three clearly distinguishable kinds of dioctahedral clay minerals: (1) detrital grains of micrometer-sized, mature muscovite; (2) small packets in the matrix consisting of dominant (Reichweite) R1 I-S or (3) small packets of illite. The illite and I-S stacks occur separately and have similar textures, with packet thicknesses averaging --400 A, within the range of anchizonal illite. Illite and detrital muscovite commonly display strain features typical of the effects of tectonic stress. Void space within I-S or iilite packets is inferred to be a strain feature, and to have served as pathways for fluids. Detrital muscovite shows abundant alteration features including (001) boundaries which are continuous with parallel packets of I-S; individual layers commonly show along-layer transitions of muscovite to smectite or I-S. Trioctahedral clays consist primarily of detrital chlorite which commonly shows direct alteration to R1 I-S and smectite, as with detrital muscovite.Deep samples contain only unaltered, coarse detrital muscovite, and thin packets of illite forming stacks and comprising most of the matrix. The texture of the illite appears to be identical to that of shallow samples, with characteristics such as packet size typical of anchizonal illite. Trioctahedral clays consist almost entirely of detrital grains of chlorite and corrensite. They occur as separate grains with rather constant composition, without signs of alteration.The data imply that all of the studied rocks have been subjected to a uniform anchizonal grade of metamorphism in which detrital grains were largely unchanged but matrix clays were transformed to packets of illite. The unusually abrupt transition with depth from highly expandable I-S to illite is inferred to actually be the result of subsequent alteration of authigenic illite and detrital chlorite and muscovite to R1 I-S and smectite in shallow rocks. This late overprinting of the anchimetamorphic clay mineral assemblage is inferred to have been locally caused by fluids with temperatures less than those of peak metamorphism. This process, called "retrograde diagenesis", gave rise to a sequence of dioctahedral I-S and illite which mimics classic prograde sequences. Interpretations of such sequences as being prograde, especially in cases of ancient rocks, should be interpreted with caution when high-resolution images of textures are not available.

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Clay Minerals in the MacAdams Sandstone, California: Implications for Substitution of H₃O⁺ and H₂O and Metastability of Illite

Cited by 23 publications

References 24 publications

Polymorphic relation between cavansite and pentagonite: Genetic implications of oxonium ion in cavansite

Polymorphic relation between cavansite and pentagonite: Genetic implications of oxonium ion in cavansite

Microtextures and the Origin of Muscovite-Kaolinite Intergrowths in Sandstones of the Utrillas Formation, Basque Cantabrian Basin, Spain

“Retrograde Diagenesis” of Clay Minerals in the Precambrian Freda Sandstone, Wisconsin

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