Topic
Margarite
About: Margarite is a research topic. Over the lifetime, 139 publications have been published within this topic receiving 3095 citations.
Papers published on a yearly basis
Papers
TL;DR: In this article, the authors compare the frictional strength of 17 sheet structure mineral powders, measured under dry and water-saturated conditions, to identify the factors that cause many of them to be relatively weak.
Abstract: [1] We compare the frictional strengths of 17 sheet structure mineral powders, measured under dry and water-saturated conditions, to identify the factors that cause many of them to be relatively weak The dry coefficient of friction μ ranges upward from 02 for graphite, leveling off at 08 for margarite, clintonite, gibbsite, kaolinite, and lizardite The values of μ (dry) correlate directly with calculated (001) interlayer bond strengths of the minerals This correlation occurs because shear becomes localized along boundary and Riedel shears and the platy minerals in them rotate into alignment with the shear planes For those gouges with μ (dry) < 08, shear occurs by breaking the interlayer bonds to form new cleavage surfaces Where μ (dry) = 08, consistent with Byerlee's law, the interlayer bonds are sufficiently strong that other frictional processes dominate The transition in dry friction mechanisms corresponds to calculated surface energies of 2–3 J/m2 Adding water causes μ to decrease for every mineral tested except graphite If the minerals are separated into groups with similar crystal structures, μ (wet) increases with increasing interlayer bond strength within each group This relationship also holds for the swelling clay montmorillonite, whose water-saturated strength is consistent with the strengths of nonswelling clays of similar crystal structure Water in the saturated gouges forms thin, structured films between the plate surfaces The polar water molecules are bonded to the plate surfaces in proportion to the mineral's surface energy, and μ (wet) reflects the stresses required to shear through the water films
317 citations
TL;DR: In this paper, a basic research program to determine fundamental phenomena involved in lubrication by graphite and other lamellar solids is described, where a theoretical calculation of the interlamellar binding energy of the ideal graphite lattice is described.
190 citations
TL;DR: Chimia et al. as discussed by the authors used X-ray photoelectron spectroscopy (XPS) to study the adsorption of Cs-, Ba-, Cu-, Zn-, and Pb-ions on the external surfaces of various, well characterized 2:1 layer silicates (micas and illites).
127 citations
TL;DR: Chromian kyanites with a maximum content of 2.88 wt.% Cr2O3 occur in metachert and amphibolite from the Southern Alps, New Zealand.
Abstract: Chromian kyanites with a maximum content of 2.88 wt.% Cr2O3 occur in metachert and amphibolite from the Southern Alps, New Zealand. The presence of the whiteschist assemblage kyanite-talc, together with kyanite-zoisite assemblages in calc silicate bands imply high pressure metamorphism, with climactic conditions of approximately 10 kb at 650°–700° C. Mylonitization caused by a change to oblique-slip movements on the Alpine Fault is succeeded by retrograde alteration of kyanite-bearing assemblages. Kyanite is pseudomorphed by Cr-margarite-fuchsite-Cr-zoisite assemblages in metachert and by less chromian margarite and zoisite in amphibolite. Contemporaneously hornblende and phlogopite break down to chlorite. Subsequently the metachert pseudomorphs are mantled by muscovite and those in amphibolite by anorthite and chromite. The breakdown of margarite and zoisite to anorthite implies decompression under a low thermal gradient, compatible with almost isothermal uplift on the Alpine Fault. Late stage retrograde products include fibrous kyanite (probably forming by recrystallization of primary alluminosilicate) and scapolite (possibly orginating through interaction of Cl-bearing fluids in a geothermal system).
123 citations
TL;DR: In this paper, the activities of thermodynamic components of clay minerals corresponding in composition to pyrophyllite, muscovite, paragonite, and margarite were computed from chemical analyses reported in the literature assuming ideal mixing of atoms on homological sites in the minerals.
Abstract: The activities of thermodynamic components of clay minerals corresponding in composition to pyrophyllite, muscovite, paragonite, and margarite were computed from chemical analyses reported in the literature assuming ideal mixing of atoms on homological sites in the minerals. These activities were then used to generate stability fields for smectites, illites, and mixed-layer clays on logarithmic activity diagrams representing equilibrium among minerals and aqueous solutions at 25°C and 1 bar. Comparative analysis indicates that the approach affords close approximation of both mineral and water compositions in geologic systems.
115 citations
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2020 | 1 |
| 2019 | 2 |
| 2018 | 1 |
| 2017 | 1 |
| 2014 | 2 |
| 2013 | 3 |