Magnetic anisotropy of some phyllosilicates

Borradaile, Graham J.; Werner, Tomasz

doi:10.1016/0040-1951(94)90196-1

Cited by 129 publications

(74 citation statements)

References 48 publications

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“…In the last group biotite and amphibole are the dominant mineral phases. In this case the MS (100-350 9 10 -6 SI) is controlled by the ferromagnesian minerals (BORRADAILE and WERNER, 1994;BENN et al, 1998). This zonation is in good agreement with the petrographic zonations of the Harşit granitoid suggested by CERYAN (1999).…”

Section: Significance Of Ams Patterns In the Harşit Granitoidsupporting

confidence: 74%

Assessment of Petrophysical Surface Data of the Harşit Granitoid in Trabzon, in Northeastern Turkey

Aydın

Ceryan

2011

Pure Appl. Geophys.

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The Harşit granitoid in northeastern Turkey, comprises four separate granite units that are apparently unfoliated. The Harşit granitoid was investigated here by using microstructural, petrofabric and anisotropy of magnetic susceptibility (AMS) data. The structural data of the granitoid were found to be highly compatible with the zonation recognized from AMS measurements. The orientation of magnetic fabrics within the granite units indicates that tectonic deformation might have occurred coevally with the magmatic emplacement of the intrusion. When we evaluated the manners on the scale of the pluton that the disruption took place in the form of uplifting, probably related to a rapid migration of the volcanic front and the documented change from deep sea sedimentation predominant until late Cretaceous to shallower environments during the Paleocene. The possible tectonic control of fault systems on the ascent and emplacement of the granitic magma in the study area, however, cannot be completely ruled out because the Harşit granitoid is situated at or very near the NAF systems in northern Anatolia. In any case, the intrusion is clearly discordant to the regional deformational features formed during the collisional events between the Eurasia and Anatolia plates in northern Turkey.

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Section: Significance Of Ams Patterns In the Harşit Granitoidsupporting

confidence: 74%

Assessment of Petrophysical Surface Data of the Harşit Granitoid in Trabzon, in Northeastern Turkey

Aydın

Ceryan

2011

Pure Appl. Geophys.

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“…This can be attributed to the increasing importance of paramagnetic silicates in the susceptibility and anisotropy as the susceptibility declines down to 10 − 3 SI. For a very low susceptibility, say less than 0.30 mSI, the contribution to the AMS of paramagnetic silicates becomes dominant and the ferrimagnetic grains, if any are available, occur as submicroscopic inclusions usually hosted in silicates (Rochette, 1987;Borradaile and Werner, 1994). The different grain sizes of magnetite are also evidenced in the thermomagnetic curves.…”

Section: Significance Of Magnetic Fabrics In the Migmatitementioning

confidence: 92%

Timing of the HT/LP transpression in the Neoproterozoic Seridó Belt (Borborema Province, Brazil): Constraints from UPb (SHRIMP) geochronology and implications for the connections between NE Brazil and West Africa

et al. 2013

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“…For each sample i (1≤i≤6), the symmetry T i which varies from −1 (prolate ellipsoid) to 1 (oblate ellipsoid) and the eccentricity P i , are the Jelinek (1981) parameters defined as (Borradaile and Werner, 1994):…”

Section: Low Field Magnetic Measurements (Ams)mentioning

confidence: 99%

Magnetic and shape fabrics of magnetite in simple shear flows

Arbaret

Launeau

Diot

et al. 2013

Journal of Volcanology and Geothermal Research

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International audienceThe magnetite fabrics measured by anisotropy of magnetic susceptibility (AMS) and by shape preferred orientation (SPO) optical methods are classically used as flow kinematics indicators in lava flows. The development of magnetite fabrics during simple shear strains γ ≤ 20 was performed using a suspension of 1% volume fraction of multidomain magnetite randomly contained in a mixture of silicone and wax. We measured AMS fabric and SPO ellipsoids by calculating a quadratic shape tensor from oriented thin-sections. For γ < 8, fabrics obey to the theoretical model of rotation of Jeffery (1922). Fabrics are usable to determine the flow kinematics, including the amount of applied finite strain. For γ > 8, fabric elements, foliation and lineation, are stabilised closely parallel to the flow plane and the shear direction, respectively. Two- and three-dimensional numerical simulations using measured aspect ratios of magnetite point out that the large scattering of aspect ratios and the initial orientation distribution of particles are together responsible for a wide-ranging loss of periodicity. The stable AMS and SPO fabrics observed at large strains in experiments are the result of these primary fabric properties combined to collisions between particles and, possibly, their complex three-dimensional shapes. In addition, the constant angular relationship observed at large strains between fabrics and flow components is related to the transient collisions. Consequently, the determination of the lava flow kinematics by using fabric properties measured either by AMS or by SPO analyses should be indubitably associated to a detailed study of the three-dimensional shape of the solid carriers. Regularly shaped populations of low elongated particles will be capable to produce cyclic to oscillating fabrics, while the fabric of elongated particles will be more sensitive to the shape parameters and collisions, ultimately favouring stable fabrics at large strains

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Magnetic anisotropy of some phyllosilicates

Cited by 129 publications

References 48 publications

Assessment of Petrophysical Surface Data of the Harşit Granitoid in Trabzon, in Northeastern Turkey

Assessment of Petrophysical Surface Data of the Harşit Granitoid in Trabzon, in Northeastern Turkey

Timing of the HT/LP transpression in the Neoproterozoic Seridó Belt (Borborema Province, Brazil): Constraints from UPb (SHRIMP) geochronology and implications for the connections between NE Brazil and West Africa

Magnetic and shape fabrics of magnetite in simple shear flows

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