Lap shear testing of biotite and phlogopite crystals and the application of interferometric strain/displacement gages to mineralogy

Noe, David C.; LaVan, David A.; Veblen, David R.

doi:10.1029/1999jb900074

Cited by 7 publications

(2 citation statements)

References 20 publications

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“…Sample preparation largely involved removal of weathered surfaces. The E-series biotite of Noe et al [1999] and the biotite studied by Kronenberg et al [1990] also come from Bancroft, Ontario.…”

Section: A12 Biotitementioning

confidence: 99%

Crystallographic controls on the frictional behavior of dry and water‐saturated sheet structure minerals

2004

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[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 m ranges upward from 0.2 for graphite, leveling off at 0.8 for margarite, clintonite, gibbsite, kaolinite, and lizardite. The values of m (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 m (dry) < 0.8, shear occurs by breaking the interlayer bonds to form new cleavage surfaces. Where m (dry) = 0.8, 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/m 2 . Adding water causes m to decrease for every mineral tested except graphite. If the minerals are separated into groups with similar crystal structures, m (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 m (wet) reflects the stresses required to shear through the water films.

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Section: A12 Biotitementioning

confidence: 99%

Crystallographic controls on the frictional behavior of dry and water‐saturated sheet structure minerals

2004

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“…Previous work concerning the effect of strain on biotite has been performed on samples that were deformed under laboratory conditions (i.e. Kronenberg, 1990;Christoffersen and Kronenberg, 1993;Noe et al, 1999) or natural processes Sánchez-Navas and Galindo-Zaldivar, 1993;Ooteman et al, 2003). High-resolution transmission electron microscopy (HRTEM) is especially useful to investigate the transformation of sheet silicates and the chloritization of biotite.…”

Section: Introductionmentioning

confidence: 99%

Deformation-promoted defects and retrograde chloritization of biotite in slates from a shear zone, Southern Iberian Massif, SE Spain

Jiménez-Millán

Vázquez

Velilla

2007

Clays and clay miner.

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Naturally deformed biotite in contact-metamorphosed slates affected by a shear zone of the Southern Iberian Massif near Jaén (SE Spain) were studied by X-ray diffraction, optical microscopy, scanning electron microscopy, electron probe microanalysis and high-resolution transmission and analytical electron microscopy. Biotite is found in the contact metamorphism aureole produced by the intrusion of a granodioritic stock, but shear strain caused its deformation. The southern part of the shear band is strongly deformed, containing thick clay gouge zones. The northern part is less deformed and develops weaker planar-linear fabrics. X-ray diffraction data reveal the predominance of the 2M 1 biotite in the undeformed samples whereas the 1M polytype is predominant in the sheared samples. Chemical data and electron images of the biotite from unsheared slates do not show the presence of intercalated phases. This biotite is almost defect-free and electron diffraction patterns have sharp reflections indicating a twolayer polytype (probably 2M 1 ). Back-scattered electron images from the deformed biotite in the moderate deformation part of the shear zone do not reveal intergrown minerals, but the electron microprobe analyses show some Fe-and Mg-enriched compositions. Transmission electron microscopy indicates that disordered polytype packets are predominant (probably 1M d ). Their electron diffraction patterns have diffuse streaking along c*. These packets have high dislocation densities, microcavities with~5 Å latticefringe regions (probably brucite-like sheets) and interlayering of chlorite-berthierine. Kaolinized biotite can be observed in the clay gouges from the strongly deformed south part of the shear zone. The degree of streaking, as an indication of the intensity of deformation, revealed that the disordered polytype packets are more deformed than the two-layer polytype packets. The microcavities of the disordered polytype packets could act as potential channels for transport of fluids during the shearing stage and serve as sites for chloritization of biotite, producing chlorite-berthierine domains within biotite. Berthierine is an intermediate metastable phase replaced by chlorite with along-layer transitions.

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Tensile testing of microsamples

LaVan

Sharpe

1999

Experimental Mechanics

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Structural analysis has advanced rapidly to the point where lack of knowledge about the local inhomogeneity and anisotropic nature of the materials prevents the accurate prediction of the behavior; models can incorporate local material properties provided they can be experimentally determined. Conventional tensile techniques are unable to test specimens from submillimeter-sized regions, and microhardness measurements do not reveal directional variations. A system has been developed to perform tensile tests on microsamples that are 3.1 mm long with a gage cross section that is 0.2 mm square. The volume of the test region is roughly 500,000 times smaller than a standard half-inch diameter specimen. Tensile stress-strain curves are measured, and the yield strength, ultimate strength, modulus and elongation are calculated for each sample. Samples cut from the weld metal of undermatched welds in HY-100 plate showed a large variation in properties from the center of the weld to the outer edge, as well as anisotropy at some locations. The average mechanical properties of a group of microsamples cut from the outer region of the weldment compared favorably with measurements made using full-sized specimens; the variation in the microsample measurements reflect local variations in the material that are not measured with full-sized specimens.

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Lap shear testing of biotite and phlogopite crystals and the application of interferometric strain/displacement gages to mineralogy

Cited by 7 publications

References 20 publications

Crystallographic controls on the frictional behavior of dry and water‐saturated sheet structure minerals

Crystallographic controls on the frictional behavior of dry and water‐saturated sheet structure minerals

Deformation-promoted defects and retrograde chloritization of biotite in slates from a shear zone, Southern Iberian Massif, SE Spain

Tensile testing of microsamples

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