Some garnet microstructures: an illustration of the potential of orientation maps and misorientation analysis in microstructural studies

Prior, David J.; Wheeler, John; Peruzzo, L.; Spiess, Richard; Storey, Craig

doi:10.1016/s0191-8141(01)00087-6

Cited by 204 publications

(127 citation statements)

References 39 publications

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“…All samples have maxima at [001], and the high-strain samples also have maxima at [010]. In terms of tilt and twist walls, tilt walls will have a misorientation axis perpendicular to both the Burgers vector and the normal to the slip plane of the dominant dislocations, while twist walls will have a misorientation axis perpendicular to the Burgers vectors and parallel to the normal to the slip plane [e.g., Kruse et al, 2001;Prior et al, 2002] [20] Crystallographic preferred orientations (CPOs) agree with this interpretation. In the pole figures of orientation data in Figure 4, all samples exhibit a common, although weak, fabric with girdles of [100] and [001] axes perpendicular to the compression direction and [010] maxima parallel to the compression direction.…”

Section: Microstructural Resultsmentioning

confidence: 99%

Grain boundary sliding in San Carlos olivine: Flow law parameters and crystallographic-preferred orientation

2011

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[1] We performed triaxial compressive creep experiments on aggregates of San Carlos olivine to develop a flow law and to examine microstructural development in the dislocationaccommodated grain boundary sliding regime (GBS). Each experiment included load and temperature steps to determine both the stress exponent and the activation energy. Grain boundary maps, created with electron backscatter diffraction data, were used to quantify grain size distributions for each sample. Inversion of the resulting data produced the following flow law for GBS: _ " GBS = 10 4.8 ± 0.8 (s (010)[100] slip system contributes significantly to deformation. We propose that these experimental results are best modeled by a deformation mechanism in which strain is accomplished primarily through grain boundary sliding accommodated by the motion of dislocations. Extrapolation of our flow laws to mantle conditions suggests that GBS is likely to be the dominant deformation mechanism in both lithospheric shear zones and asthenospheric flow, and therefore strong upper mantle seismic anisotropy can not be attributed solely to the dominance of dislocation creep.

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Section: Microstructural Resultsmentioning

confidence: 99%

Grain boundary sliding in San Carlos olivine: Flow law parameters and crystallographic-preferred orientation

2011

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“…Processing and presentation of EBSD data Non-indexed solutions were replaced by the most common neighbour orientation to reduce data noise, following the procedure tested by Prior et al (2002) and Bestmann and Prior (2003). The resulting data are presented in form of pole figures (upper hemisphere, equal angle stereographic projection) and of colour-coded maps.…”

Section: Electron Backscatter Diffraction (Ebsd) Analysismentioning

confidence: 99%

“…Prior et al 2002;Barrie et al 2008;Piazolo et al 2008) is a method for determining the geometry of low-angle boundary and the active slip system(s) from EBSD data. When the 3D orientation of a boundary is unknown, the boundary trace analysis provides a crystallographically consistent solution for the boundary geometry, if ideal tilt and twist boundary models are assumed.…”

Section: Boundary Trace Analysismentioning

confidence: 99%

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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“…Some domains of the grain yielded poor quality EBSPs and were unable to be indexed. The average Slip systems were resolved from EBSD data using a simple geometric approach that relates the geometry of low-angle tilt and twist boundaries and the dislocations responsible for their formation 21, [25][26][27] . The map trace of the boundary and the crystallographic dispersion axis were used to reconstruct the 3D boundary orientation, and in turn relate the boundary and dispersion axis orientation to dislocation slip plane and slip direction by assuming end-member tilt boundary models.…”

Section: Electron Backscatter Diffraction (Ebsd)mentioning

confidence: 99%

Timing of crystallization of the lunar magma ocean constrained by the oldest zircon

et al. 2009

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Some garnet microstructures: an illustration of the potential of orientation maps and misorientation analysis in microstructural studies

Cited by 204 publications

References 39 publications

Grain boundary sliding in San Carlos olivine: Flow law parameters and crystallographic-preferred orientation

Grain boundary sliding in San Carlos olivine: Flow law parameters and crystallographic-preferred orientation

The effect of Dauphiné twinning on plastic strain in quartz

Timing of crystallization of the lunar magma ocean constrained by the oldest zircon

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