Frequency dependence and the electromagnetic susceptibility tensor in magnetic fabric studies — a discussion

Puranen, R.; Poikonen, Ari; Puranen, M.

doi:10.1016/0031-9201(94)02990-s

Cited by 3 publications

(2 citation statements)

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“…It has been shown that there exists a clear frequency dependence for some paramagnetic and diamagnetic minerals that readily conduct currents at frequencies higher than 500 Hz (Ellwood et al 1993;Puranen et al 1995). Kukkonen and Pesonen (1983), using a frequency of 1000 Hz, found no appreciable conductivity effect for chondrites.…”

Section: Frequency Dependence Of Magnetic Susceptibilitymentioning

confidence: 99%

Stony meteorite characterization by non‐destructive measurement of magnetic properties

Smith

Ernst

Samson

et al. 2006

Meteorit & Planetary Scien

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All appendix tables for this article are available online at http://meteoritics.org.Abstract-Four parameters of low-field magnetic susceptibility (bulk value, frequency dependence, degree of anisotropy, and ellipsoid shape) have been determined for 321 stony meteorites from the National Collection of Canada. These parameters provide a basis for rapid, non-destructive, and accurate meteorite classification as each meteorite class tends to have a distinct range of values.Chondrites show a clear trend of increasing bulk susceptibility from LL to L to H to E within the 3.6 to 5.6 logχ (in 10 −9 m 3 /kg) range, reflecting increasing Fe-Ni metal and Fe-Ni sulfide content. Achondrite values range in logχ from 2.4 to 4.7 and primitive achondrites from 4.2 to 5.7. Frequency dependence is observed, using 19,000 Hz and 825 Hz, with variations in strength among meteorite classes and individual specimen dependence ranging from 1-25.6%. Degrees of anisotropy range from 1 to 53% with both oblate and prolate ellipsoids present. The aubrite class is marked by high degrees of anisotropy, low bulk magnetic susceptibility, and prolate fabric. Camel Donga is set apart from other eucrites, marked by higher bulk susceptibility, degree of anisotropy, and magnitude of oblate ellipsoid shape. The Shergotty, Nakhla, and Chassigny (SNC) meteorites show subclass distinction using frequency dependence and Chassigny is set apart with a relatively strong oblate fabric. The presence of both strong oblate and prolate fabrics among and within meteorite classes of chondritic and achondritic material points to a complex, multi-mechanism origin for anisotropy, more so than previously thought, and likely dominated by impact processes in the later stages of stony parent body formation.

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Section: Frequency Dependence Of Magnetic Susceptibilitymentioning

confidence: 99%

Stony meteorite characterization by non‐destructive measurement of magnetic properties

Smith

Ernst

Samson

et al. 2006

Meteorit & Planetary Scien

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“…Field dependence of magnetic minerals can be mistaken as a frequency dependence of magnetic susceptibility (Worm 1991;de Wall 2000;Jackson et al 1998), however this cannot explain the dependence observed in the present study as both the 19000 and 825 Hz coils operate at the same applied magnetic field strength of 24 A/m. (2) (7) (1) (7) (5) (1) (5) (1) (1) (2) ( It has been shown that there exists a clear frequency dependence for some paramagnetic and diamagnetic minerals that readily conduct currents at frequencies higher than 500 Hz (Ellwood et al 1993;Puranen et al 1995). Kukkonen and Pesonen (1983), using a frequency of 1000 Hz, found no appreciable conductivity effect for chondrites.…”

Section: Frequency Dependence Of Magnetic Susceptibilitymentioning

confidence: 99%

Non-destructive characterization of stony meteorites

Smith¹

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The characterization of meteoritic material is of fundamental importance to our understanding of the solar system and its processes of formation. Many meteorites are small, fragile and unique and thus the identification and subsequent preservation of this material is a priority. The present study investigates two non-destructive techniques of meteorite characterization and classification.A new method of density determination and surface roughness description using 3D laser imaging has been evaluated on eleven stony meteorites. In addition, four magnetic parameters that show promise as classification tools were evaluated on 321 stony meteorite specimens: bulk magnetic susceptibility and its frequency dependence (825 and 19000 Hz), and the degree and shape of the anisotropy of magnetic susceptibility.Densities determined using 3D laser imaging compare very well with previously published values. 3D laser imaging is the least invasive method of density measurement currently available and may provide a more accurate estimate of the meteorite's bulk volume than other methods. A measure of surface roughness is proposed using a pilot approach.Chondrites show a clear trend of increasing bulk susceptibility from LL, L, H to E probably governed by Fe-Ni metal and sulphide content; achondrite values are more varied. Frequency dependence is observed with variations in magnitude among meteorite classes. Degrees of anisotropy range from 1 -53%. Strong oblate and prolate fabrics are observed among and within meteorite classes of chondritic and achondritic material pointing to a complex, multi-mechanism origin for anisotropy, more so than previously thought, and likely dominated by impact processes in the later stages of stony parent body formation.iii Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

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