Lattice preferred orientation of graphite determined by the anisotropy of out-of-phase magnetic susceptibility

2022 ◽  
Vol 154 ◽  
pp. 104491
Author(s):  
František Hrouda ◽  
Jan Franěk ◽  
Stuart Gilder ◽  
Martin Chadima ◽  
Josef Ježek ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Preferred Orientation ◽  
Lattice Preferred Orientation

scholarly journals UM MODELO PARA A EVOLUÇÃO MICROESTRUTURAL DOS MINÉRIOS DE FERRO DO QUADRILÁTERO FERRÍFERO. PARTE II – TRAMA, TEXTURA E ANISOTROPIA DE SUSCEPTIBILIDADE MAGNÉTICA

1996 ◽  
Author(s):  
C. A. Rosière ◽  
H. Quade ◽  
H. Siemes ◽  
F. Chemale Jr. ◽  
E. M. Resende de Souza
Keyword(s):  
Magnetic Susceptibility ◽  
Grain Growth ◽  
Iron Ore ◽  
Preferred Orientation ◽  
Oblate Shape ◽  
Lattice Preferred Orientation ◽  
Prolate Shape ◽  
Quadrilátero Ferrífero

Low strain itabirite still displays primary features similar to jaspilites such as sedimentary layeringand a porous granoblastic fabric composed of martite with magnetite relics and hematite Due tosynmetamorphic deformation this mineralogy recrystallizes in specularite producing a variety of fabrics,textures and anisotropy of the magnetic susceptibility (AMS) depending mainly on the strain conditions.Folded ores usually display a foliation parallel to the banding due to flexural slip and an axial planeschistosity that results in a lepidogranoblastic fabric. The stereogram of the {11.0} texture is a singlemaximum parallel to the intersection lineation. The AMS is low and its ellipsoid is triaxial. Increasingstrain and shearing transposes and obliterates the primary banding, resulting in iron ore mylonites withlepidoblastic (S-tectonites) or nematoblastic (L-tectonites) fabrics probably depending on the shape of thestrain ellipsoid.The stereogram of the {11.0} texture of schistose ores is typically a girdle parallel to foliation. AMSintensity is high with oblate shape. Stereograms of the texture of lineated ores display a single maximumparallel to the stretch lineation. AMS is low to moderate with prolate shape. Secondary recrystallizationand grain growth does not affect the lattice preferred orientation.

Titanohematite lattice-preferred orientation and magnetic anisotropy in high-temperature mylonites

2002 ◽  
Vol 198 (1-2) ◽  
pp. 77-92 ◽  
Author(s):  
Jérôme Bascou ◽  
M.Irene B. Raposo ◽  
Alain Vauchez ◽  
Marcos Egydio-Silva
Keyword(s):  
High Temperature ◽  
Magnetic Anisotropy ◽  
Preferred Orientation ◽  
Lattice Preferred Orientation

Lattice preferred orientation in CaIrO3 perovskite and post-perovskite formed by plastic deformation under pressure

2007 ◽  
Vol 34 (9) ◽  
pp. 679-686 ◽  
Author(s):  
Ken Niwa ◽  
Takehiko Yagi ◽  
Kenya Ohgushi ◽  
Sébastien Merkel ◽  
Nobuyoshi Miyajima ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Preferred Orientation ◽  
Lattice Preferred Orientation

A Discussion on natural strain and geological structure - Strain and anisotropy in rocks

1976 ◽  
Vol 283 (1312) ◽  
pp. 27-42 ◽  
Keyword(s):  
Magnetic Susceptibility ◽  
Shear Wave ◽  
Finite Strain ◽  
Preferred Orientation ◽  
Seismic Velocities ◽  
Magnetic Susceptibility Anisotropy ◽  
Wave Velocities ◽  
Natural Strain ◽  
Shear Wave Velocities ◽  
Wide Range

The evaluation of finite strain in naturally deformed rocks is restricted by the limited occurrence of good natural strain indicators which are also homogeneous with respect to the matrix. This problem is overcome by establishing the relation between measured finite strain and those physical behaviour characteristics of rocks that are dependent upon the anisotropy resulting from deformation. Accordingly, the strain measured from natural indicators is calibrated against ( degree of preferred orientation, (b) magnetic susceptibility anisotropy, and (r) seismic anisotropy. This _ will permit three approaches to be used independently for the evaluation of strain, provided that a minimal number of actual strains are available. The relation between measured strain and the degree of preferred orientation of layer silicates as revealed by X-ray transmission goniometry is established for a group of fine grained tectonites of dominantly planar fabric which have an average deformation ellipsoid of form 1.6:1 :,0.26. The strains measured from the degree of preferred orientation are in remarkable agreement with those measured from natural strain indicators. The measured deformation ellipsoids for a wide range of strains are also compared to the correlative ellipsoids of magnetic susceptibility anisotropy. The axes of both sets of ellipsoids are coincidental and the shape relationship between deformation and magnetic susceptibility ellipsoids is established by linear regression. Finally, the anisotropy of seismic velocities is determined by measuring the pseudocompressional velocity and two orthogonally polarized pseudo shear wave velocities for each of a minimum of nine non-coplanar directions. The velocity surfaces thus obtained define an elastic or seismic velocity anisotropy ellipsoid, the axes of which are also precisely coincidental with those of the finite deformation ellipsoid. The influence of rock fabric upon seismic velocities is such that for a rock which has undergone a principal finite extension of 135 % and a finite shortening of 65 %, the difference of compressional and shear wave velocities between these two directions is in the ratio 1.26:1 for P waves and 1.33:1 for S waves.

New lattice preferred orientation(LPO) of amphibole experimentally found in simple shear

2020 ◽  
Author(s):  
Junha Kim ◽  
Haemyeong Jung
Keyword(s):  
Grain Size ◽  
High Pressure ◽  
Shear Strain ◽  
Seismic Anisotropy ◽  
Preferred Orientation ◽  
Shear Direction ◽  
High Shear ◽  
Type Iv ◽  
Lower Shear ◽  
Lattice Preferred Orientation

<p>The lattice preferred orientation(LPO) of amphibole has a large effect on seismic anisotropy in the crust. Previous studies have reported four LPO types (I–IV) of amphibole, but the genesis of type IV LPO, which is characterized by [100] axes aligned in a girdle subnormal to the shear direction, is unknown. In this study, shear deformation experiments on amphibolite were conducted to find the genesis of type IV LPO at high pressure (0.5 GPa) and temperature (500–700 °C). The type IV LPO was found under high shear strain (γ > 3.0) and the sample exhibited grains in a range of sizes but generally smaller than the grain size of samples with lower shear strain. The seismic anisotropy of type IV LPO is lower than in types I-III. The weak seismic anisotropy of highly deformed amphibole could explain weak seismic anisotropy observed in the middle crust.</p>

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