Formation of Clay Minerals During Low Temperature Experimental Alteration of Obsidian

Kawano, Motoharu; Tomita, Katsutoshi; Kamino, Yoshitaka

doi:10.1346/ccmn.1993.0410404

Cited by 33 publications

(25 citation statements)

References 28 publications

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“…Following the procedures of Kawano and Tomita (1992) and Kawano et al (1993) to synthesize beidellite by hydrothermal alteration of volcanic glass, Tomita et al (1993) synthesized Fe3 § at 90-100~ and ambient pressure by reaction of volcanic glass with NaOH. The ratio of glass to NaOH determined whether a smectite or a zeolite (P, E, or chabazite) formed, although a large overlap was observed.…”

Section: Saponitementioning

confidence: 99%

“…Apparently, the slightly acidic conditions of the experiment inhibited the formarion of analcime. Kawano and Tomita (1992) and Kawano et al (1993) studied the formation of beidellite and allophane (a very poorly crystalline aluminosilicate) during hydrothermal treatment of obsidian (volcanic glass). They observed the formation of allophane as the first alteration product after treatment of the glass in distilled water at 150-200~…”

Section: Beidellitementioning

confidence: 99%

See 1 more Smart Citation

Synthesis of Smectite Clay Minerals: A Critical Review

Kloprogge

Komarneni

Amonette

1999

Clays and clay miner.

318

153

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Abstract--Smectites are one of the most important groups of phyllositicates found in soils and sediments, and certainly one of the most difficult to study. New information about the formation mechanisms, impact of structural features on surface properties, and long-term stability of smectites can best be gained from the systematic study of single-phase specimens. In most instances, these specimens can only be obtained through synthesis under controlled conditions. Syntheses of smectites have been attempted (1) at ambient pressure and low-temperature (< 100~(2) under moderate hydrothermal conditions (100-1000~ pressures to several kbars), (3) under extreme hydrothermal conditions (>1000~ or pressures >10 kbars), and (4) in the presence of fluoride. Of these approaches, syntheses performed under moderate hydrothermal conditions are the most numerous and the most successful in terms of smectite yield and phasepurity. Using hydrothermal techniques, high phase-purity can be obtained for beidellites and several transition-metal smectites. However, synthesis of montmorillonite in high purity remains difficult. Starting materials for hydrothermal syntheses include gels, glasses, and other aluminosilicate minerals. The presence of Mg 2+ seems to be essential for the formation of smectites, even for phases such as montmorillonite which contain low amounts of Mg. Highly crystalline smectites can be obtained when extreme temperatures or pressures are used, but other crystalline impurities are always present. Although the correlation between synthesis stability fields and thermodynamic stability fields is good in many instances, metastable phases are often formed. Few studies, however, include the additional experiments (approach from underand over-saturation, reversal experiments) needed to ascertain the conditions for formation of thermodynamically stable phases. Thorough characterization of synthetic products by modern instrumental and molecular-scale techniques is also needed to better understand the processes leading to smectite formation.

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Section: Saponitementioning

confidence: 99%

Section: Beidellitementioning

confidence: 99%

Synthesis of Smectite Clay Minerals: A Critical Review

Kloprogge

Komarneni

Amonette

1999

Clays and clay miner.

318

153

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“…Kinetic effects (e.g., low temperatures, short alteration times) influence the formation of poorly crystalline phases such as hydrotalcite (Abdelouas et al, 1994) and allophane Tomita, 1992, 1995;Kawano et al, 1993). Low pH promotes the formation of halloysite and kaolinite (Nagasawa, 1978;Kawano and Tomita, 1995), neutral and slightly basic conditions favor smectite formation Ghiara et al, 1993;, and basic pH values promote zeolite formation (Mariner and Surdam, 1970;Hall, 1998).…”

Section: Introductionmentioning

confidence: 99%

“…Hydrothermal alteration may involve illite or I-S formation directly from a glass precursor (Lanson and Champion, 1991;Zevenbergen et aL, 1996). Reported mechanisms of volcanic glass alteration include the following: 1) formation of an alteration layer on the glass surface by incongruent glass dissolution and selective trapping of dissolved ions (Thomassin et al, 1989;Magonthier et al, 1992;Kawano et al, 1993), 2) congruent dissolution of glass and precipitation of new phases (Crovisier et aL, 1992), and 3) formation of protocrystalline domains within the glass that evolve to new crystalline phases (Tazaki et al, 1989;Fiore et al, 1999). The latter mechanism implies long ion-diffusion paths through the glass.…”

Section: Introductionmentioning

confidence: 99%

Electron Microscopy Study of Volcanic Tuff Alteration to Illite-Smectite Under Hydrothermal Conditions

Fuente

Cuadros

Fiore³

et al. 2000

Clays and clay miner.

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Abstract--Experimental alteration of volcanic tuff from Almeria, southeastern Spain, was performed in solutions with different Na/K ratios (0.01, 1, 10, and 100), different total salt concentrations (0.01, 0.1, 0.2, 0.33, and 1 M), and in deionized water, at 60, 80, 120, and 160~ for periods of 60, 90, 180, and 360 d. Two particle size fractions of volcanic tuff were used: 10-200 and 20-60 p,m. Alteration products were examined by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), laser-particle size analysis, scanning electron microscopy equipped with an energy dispersive X-ray spectrometer (SEM-EDS), image computer analysis, and transmission electron microscopy with microanalysis (TEM-AEM). XRD detected neoformed phases only in the products from experiments of 180-360 d at high temperatures (120-160~and with Na/K ratios above unity and in deionized water. The synthesized phase is a random mixed-layer illite-smectite (I-S) with 75% smectite. The quantity of newly formed I-S, determined by FTIR, ranged between 3-30%. There was no apparent change in grain size and shape of the grains after the experiments as compared to before.SEM-EDS and TEM-AEM revealed the following alteration sequence: 1) intense etching on glassgrain surfaces; 2) formation of hemispherical morphologies on grain surfaces; 3) precipitation of very thin, individual flakes of illite-smectite on glass-grain surfaces; 4) development of I-S at the edges of glass grains; and 5) development of I-S honeycomb structures either covering large areas of the glass grains or resulting from the complete alteration of glass grains. A direct transformation of glass to I-S seems to be the major reaction mechanism, although there also is evidence of glass dissolution and subsequent I-S precipitation.

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“…Synthesis of smectite at elevated tempera tures and pressures from oxides and hydroxides and from various minerals has been carried out by many researchers (Noll, 1930(Noll, , 1935(Noll, and 1936Bowen and Tuttle, 1949;Yoder, 1952;Sand et al, 1953;Roy and Roy, 1.955;Tomita, 1970;Kawano and Tomita, 1992, 1994aKawano et al, 1993), but it has been rarely achieved at atmospheric pressure (Sedleckij, 1937;Tomita et al, 1993). Zeolites on the other hand are easily formed from volcanic glasses as reaction products with alkali solu tions at atmospheric pressure (Sudo and Ma tsuoka, 1959;Tomita et al, 1969;, but formation of smectite from ob sidian at 1 atm however has not yet been report ed.…”

Section: Introductionmentioning

confidence: 99%