Reaction Series for Dioctahedral Smectites

Abstract

Abstract--Several dioctahedral clay minerals are related through reaction series. These series can be produced hydrothermally from beidellite gel and montmorillonite by making simple changes in interlayer and solution chemistry. The series are:gel-K-beidellite-random illite/smectite-K-rectorite-illite; K-montmorillonite-K-rectorite-illite; Na-montmorillonite or beidellite-Na-rectorite-paragonite; Li-montmorillonite-Li-tosudite-Li-rectorite-cookeite(?); Mg-montmorillonite-Mg-rectorite-tosu dite-sudoite(?); Ca-montmorillonite-Ca-rectorite-margarite(?); AI-Ca-montmorillonite-kaolinite/smectite-kaolinite (150~ AI-Ca-montmorillonite-pyrophyllite/smectite-pyrophyllite (320~ Assuming stability for the mixed-layer phases, paragenesis is a function of P, T, and X conditions. If the phases are considered to be metastable, paragenesis is a function of the speed and path of reaction.

An Interstratified Illite/Smectite Mineral from the Hydrothermal Deposit in Sibert, Rhone, France

“…The smectite layers are beidellitic. Very similar XRD reflections were reported by Eberl and Hower (1977) for a synthetic, ordered, interstratified illite/smectite with about 35% expandable layers, a material that was subsequently called K-rectorite (Eberl, 1978).…”

Low Temperature Experimental Investigation of the Effect of High pH Naoh Solutions on the Opalinus Shale, Switzerland

“…Especially applicable to this study are those experiments conducted in the Na hydroxide systems (Barth-Wirshing and H/511er, 1989), where the starting material used was rhyolitic glass and the precipitation of analcime was observed. Experimental clay mineral transformations in shales have also been widely studied in the laboratory (Eberl, 1978;Velde, 1985;Whitney and Northrop, 1988). Directly applicable to this study is the work of Eberl (1978) and Matsuda and Henmi (1983) where the transformation of smectites and kaolinite to rectorite was observed.…”

“…Experimental clay mineral transformations in shales have also been widely studied in the laboratory (Eberl, 1978;Velde, 1985;Whitney and Northrop, 1988). Directly applicable to this study is the work of Eberl (1978) and Matsuda and Henmi (1983) where the transformation of smectites and kaolinite to rectorite was observed. The effects of high solution pH on silicate dissolution rates have been studied by Brady and Walther (1989), who showed that minerals in contact with high pH solutions have increased dissolution rates due to mineral surface speciation.…”

Diagenetic Structural Transformations in North Sea Jurassic Illite/Smectite

“…The reaction mechanism for this charge increase has been discussed in several papers. Investigation ofdiagenetic clays and hydrothermal experiments (Eberl, 1976;Eberl and Hower, 1976) indicate Copyright 9 1991, The Clay Minerals Society a transformation in which AI 3+ substitutes for Si 4+ in the tetrahedral sheet, followed by interlayer potassiu m fixation and interlayer contraction. On the other hand, combined X-ray powder diffraction (XRD) and transmission electron microscopy (TEM) studies of dispersed illitic clays from bentonites and sandstones led Nadeau et a l. (1985) to propose a neoformation mechanism, i.e., a dissolution of smectite and precipitation/ growth of thin illite particles.…”