Elastic Moduli of Quartz versus Hydrostatic Pressure at 25° and − 195.8°C

McSkimin, H. J.; Andreatch, P.; Thurston, R. N.

doi:10.1063/1.1703099

Cited by 480 publications

(119 citation statements)

References 19 publications

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“…In quartz, the maximum uniaxial compliance is nearly orthogonal to the positive rhombohedral planes {r} and is about twice the minimum value, which is orthogonal to the negative rhombohedral planes {z} (McSkimin et al 1965;Lloyd 2000). This is consistent with the experiments of Tullis (1970) and Tullis and Tullis (1972), where crystals loaded orthogonal to {z} changed their orientation by twinning.…”

Section: Ebsd Analysis Of Porphyroclasts B C D Esupporting

confidence: 79%

The effect of Dauphiné twinning on plastic strain in quartz

Menegon

Piazolo

Pennacchioni

2010

Contrib Mineral Petrol

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We present an electron backscatter diffraction analysis of five quartz porphyroclasts in a greenschist facies (T = 300-400°C) granitoid protomylonite from the Arolla unit of the NW Alps. Mechanical Dauphiné twinning developed pervasively during the incipient stage of deformation within two porphyroclasts oriented with a negative rhomb plane {z} almost orthogonal to the compression direction (z-twin orientation). Twinning was driven by the anisotropy in the elastic compliance of quartz and resulted in the alignment of the poles of the planes of the more compliant positive rhomb {r} nearly parallel to the compression direction (r-twin orientation). In contrast, we report the lack of twinning in two porphyroclasts already oriented with one of the {r} planes orthogonal to the compression direction. One twinned porphyroclast has been investigated with more detail. It shows the localization of much of the plastic strain into discrete r-twins as a consequence of the higher amount of elastic strain energy stored by r-twins in comparison to z-twins. The presence of Dauphiné twins induced a switch in the dominant active slip systems during plastic deformation, from basal \a[ (regions without twinning) to {p} and {p 0 } \a[(pervasively twinned regions). Dynamic recrystallization is localized along an r-twin and occurred dominantly by progressive subgrain rotation, with a local component of bulging recrystallization. Part of the recrystallized grains underwent rigid-body rotation, approximately about the bulk vorticity axis, which accounts for the development of large misorientation angles. The recrystallized grain size piezometer for quartz yields differential stress of 100 MPa. The comparison of this palaeostress estimate with literature data suggests that mechanical Dauphiné twinning could have a potential use as palaeopiezometer in quartz-bearing rocks.

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Section: Ebsd Analysis Of Porphyroclasts B C D Esupporting

confidence: 79%

The effect of Dauphiné twinning on plastic strain in quartz

Menegon

Piazolo

Pennacchioni

2010

Contrib Mineral Petrol

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“…Furthermore, the anisotropy of the elastic properties of quartz may also have contributed to promoting preferential failure along specific crystallographic planes (Menegon et al, 2011;McSkimin et al, 1965). This is suggested by Domain 3 (small square in Fig.…”

Section: Strain Accommodation History Within the Different Domainsmentioning

confidence: 92%

“…We interpret the second set, sub-parallel to the rhomb, as sealed fractures. It is worth noting that the positive rhomb is the most compliant crystallographic plane in quartz and, therefore, tends to localize fracturing (McSkimin et al, 1965;Lloyd, 2000;van Daalen et al, 1999). EBSD analysis reveals that some new grains developed also along these fractures, but mostly in the junctions where the two fracture sets intersect.…”

Section: Strain Accommodation History Within the Different Domainsmentioning

confidence: 99%

Brittle–viscous deformation of vein quartz under fluid-rich lower greenschist facies conditions

et al. 2015

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Abstract.We studied by Electron BackScatter Diffraction (EBSD) and optical microscopy a coarse-grained (ca. 0.5-6 mm) quartz vein embedded in a phyllonitic matrix to gain insights into the recrystallization mechanisms and the processes of strain localization in quartz deformed under lower greenschist facies conditions, broadly coincident with the brittle-viscous transition. The vein deformed during faulting along a phyllonitic thrust of Caledonian age within the Porsa Imbricate Stack in the Paleoproterozoic Repparfjord Tectonic Window in northern Norway. The phyllonite hosting the vein formed at the expense of a metabasaltic protolith through feldspar breakdown to form interconnected layers of fine, synkinematic phyllosilicates. In the mechanically weak framework of the phyllonite, the quartz vein acted as a relatively rigid body. Viscous deformation in the vein was initially accommodated by quartz basal slip. Under the prevailing deformation conditions, however, dislocation glide-and possibly creep-accommodated deformation of quartz was inefficient, and this resulted in localized strain hardening. In response to the (1) hardening, (2) progressive and cyclic increase of the fluid pressure, and (3) increasing competence contrast between the vein and the weakly foliated host phyllonite, vein quartz crystals began to deform by brittle processes along specific, suitably oriented lattice planes, creating microgouges along microfractures. Nucleated new grains rapidly sealed these fractures as fluids penetrated the actively deforming system. The grains grew initially by solution precipitation and later by grain boundary migration. We suggest that the different initial orientation of the vein crystals led to strain accommodation by different mechanisms in the individual crystals, generating remarkably different microstructures. Crystals suitably oriented for basal slip, for example, accommodated strain mainly viscously and experienced only minor fracturing. Instead, crystals misoriented for basal slip hardened and deformed predominantly by domainal fracturing. This study indicates the importance of considering shear zones as dynamic systems wherein the activated deformation mechanisms may vary through time in response to the complex temporal and spatial evolution of the shear zone, often in a cyclic fashion.

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“…The elastic constants of a-quartz single crystal (trigonal) used were those reported by McSkimin et al (1965), and for biotite (monoclinic, pseudohexa gonal) we used those recently reported by Vaughan and Guggenheim (1986) for muscovite. The seismic properties of muscovite are very close to those deter mined by biotite (considered as hexa gonal) by Aleksandrov and Ryzhova (1961).…”

Section: ____ _ùucture Is Typical Of Plastic Deformation Grains Armentioning

confidence: 99%

3D seismic study of a ductile shear zone from laboratory and petrofabric data (Saint Barthelemy Massif, Northern Pyrenees, France)

1992

International Journal of Rock Mechanics and Mining Sciences &am

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In order to constrain interpretations of seismic reflection records more effectively, the seismic properties of a middle crustal section exposed in the Saint Barthélémy Massif have been determined. The massif, transected by a 200 m thick shear zone has been systematically sampled for density measurements and modal analysis has been performed in order to define the spatial variations of physical properties. Seismic velocities (V p

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Elastic Moduli of Quartz versus Hydrostatic Pressure at 25° and − 195.8°C

Cited by 480 publications

References 19 publications

The effect of Dauphiné twinning on plastic strain in quartz

The effect of Dauphiné twinning on plastic strain in quartz

Brittle–viscous deformation of vein quartz under fluid-rich lower greenschist facies conditions

3D seismic study of a ductile shear zone from laboratory and petrofabric data (Saint Barthelemy Massif, Northern Pyrenees, France)

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