BASAL PLANE REACTIVITY OF PHYLLOSILICATES STUDIED IN SITU BY HYDROTHERMAL ATOMIC FORCE MICROSCOPY (HAFM)

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dc.contributor.author Aldushin K.
dc.contributor.author Jordan G.
dc.contributor.author Schmahl W.W.
dc.date.accessioned 2024-04-29T04:07:39Z
dc.date.available 2024-04-29T04:07:39Z
dc.date.issued 2006
dc.identifier https://elibrary.ru/item.asp?id=12091675
dc.identifier.citation Geochimica et Cosmochimica Acta, 2006, 70, 17, 4380-4391
dc.identifier.issn 0016-7037
dc.identifier.uri https://repository.geologyscience.ru/handle/123456789/43755
dc.description.abstract The basal plane reactivities of the sheet silicates apophyllite and phlogopite have been studied by hydrothermal atomic force microscopy (HAFM) in situ in aqueous solutions at temperatures from 20 to 140 °C. At pH 4-5.6 (T = 20-100 °C), the apophyllite basal surface undergoes a swelling process which forms square hillocks on the surface. The reaction comprises three sequential morphological transformations that cause swelling to increase from 0.15 to 2.5 nm. In the first two transformations, interlayer cations are replaced by hydronium ions from the solution; the third transformation involves a depolymerization and partial cross-linking of the protonated silicate sheets. The reaction of phlogopite with acidic aqueous solutions (pH 1.5-2) at high temperature (T = 100-140 °C) causes the nucleation of numerous monolayer etch pits on the pristine surface. Where the 2D pits recur at the same lateral position, they can accumulate to a total pit depth of up to 50 nm. The formation of an altered layer has also been detected at these conditions. The alteration affects the uppermost 4-5 layers. The layers are expanded, corrugated, highly unstable, and readily peel off the surface. Etch pit formation has been detected even underneath the altered layer. On the basis of HAFM data, dissolution rates and activation energies were calculated. The presented data show that the basal surface of phlogopite plays an important role in the dissolution process at least at elevated temperatures and that the absolute amount of released material has comparable contributions from both basal surfaces and edge surfaces. ? 2006.
dc.subject ACTIVATION ENERGY
dc.subject ATOMIC FORCE MICROSCOPY
dc.subject DISSOLUTION
dc.subject HIGH TEMPERATURE
dc.subject PHYLLOSILICATE
dc.subject SWELLING
dc.title BASAL PLANE REACTIVITY OF PHYLLOSILICATES STUDIED IN SITU BY HYDROTHERMAL ATOMIC FORCE MICROSCOPY (HAFM)
dc.type Статья
dc.identifier.doi 10.1016/j.gca.2006.04.015


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