Advertisement

Anisotropy of Magnetic Susceptibility in Variable Low-Fields: A Review

  • František Hrouda
Chapter
First Online:
Part of the IAGA Special Sopron Book Series book series (IAGA, volume 1)

Abstract

Theory of the Anisotropy of Magnetic Susceptibility (AMS) assumes field-independent rock susceptibility in the low fields used by common AMS meters. This is valid for rocks whose AMS is carried by diamagnetic and paramagnetic minerals and also by pure magnetite, while rocks with pyrrhotite, hematite or titanomagnetite may show significant variation of susceptibility in common measuring fields. Consequently, the use of the contemporary AMS theory is in principle incorrect in these cases. Fortunately, it has been shown by practical measurements and mathematical modelling of the measuring process that the variations of the principal directions and of the AMS ellipsoid shape with field are very weak, which is important in most geological applications. The degree of AMS, however, may show conspicuous variation with field and, if one wants to make precise quantitative fabric interpretation, it is desirable to work with the AMS of the field-independent component. Three methods exist for simultaneous determination of the field-independent and field-dependent AMS components, all based on standard AMS measurement in variable fields within the Rayleigh Law range. The field-dependence of the AMS can be used in solving some geological problems. For example, in volcanic and dyke rocks with inverse magnetic fabric, one can decide whether this inversion has geological (special flow regime of lava) or physical (SD vs. MD grains) causes. In rocks consisting of two magnetic fractions, one with field-independent susceptibility (magnetite, paramagnetic minerals) and the other possessing the field-dependent susceptibility (titanomagnetite, hematite, pyrrhotite), one can separate the AMS of the latter fraction and in favourable cases also of the former fraction.

Keywords

Susceptibility Tensor Orientation Tensor Magnetic Lineation Magnetic Foliation Initial Susceptibility 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in to check access.

Notes

Acknowledgements

Dr. Martin Chadima is thanked for providing the field-dependent AMS of the dike rock from the locality of CS27. The research was partly supported financially by the Ministry of Education and Youth of the Czech Republic (Scientific Program MSM0021620855).

References

  1. Brož J (1966) Modern problems of ferromagnetism (in Czech). NČSAV, Praha 189 ppGoogle Scholar
  2. Chadima M, Cajz V, Týcová P (2009) On the interpretation of normal and inverse magnetic fabric in dikes: examples from the Eger Graben, NW Bohemian Massif. Tectonophysics 466:47–63CrossRefGoogle Scholar
  3. Canon-Tapia E, Herrero-Bervera E, Walker GPL (1994) Flow directions and paleomagnetic study of rocks from the Azufre volcano, Argentina. J Geomagnetism Geoelectricity 46:143–159Google Scholar
  4. Cox A, Doell RR (1967) Measurements of high coercivity magnetic anisotropy. In: Collinson DV, Creer KM, Runcorn SK (eds) Methods in palaeomagnetism. Elsevier, Amsterdam, pp 477–482Google Scholar
  5. Daly L, Zinsser H (1973) Etude comparative des anisotropies de susceptibilité et d’aimantation rémanente isotherme. Conséquences pour l’analyse structurale et le paléomagnétisme. Ann Géophys 29:189–200Google Scholar
  6. De Wall H (2000) The field dependence of AC susceptibility in titanomagnetites: implications for the anisotropy of magnetic susceptibility. Geophys Res Lett 27:2409–2411CrossRefGoogle Scholar
  7. De Wall H, Nano L (2004) The use of field dependence of magnetic susceptibility for monitoring variations in titanomagnetite composition – a case study on basanites from the Vogelsberg 1996 Drillhole, Germany. Studia Geophys Geod 48:767–776CrossRefGoogle Scholar
  8. Ernst RE, Baragar WRA (1992) Evidence from magnetic fabric for the flow pattern of magma in the Mackenzie giant radiating dyke swarm. Nature 356:511–513CrossRefGoogle Scholar
  9. Henry B (1983) Interprétation quantitative de l’anisotropie de susceptibilité magnétique. Tectonophysics 91:165–177CrossRefGoogle Scholar
  10. Henry B, Daly L (1983) From qualitative to quantitative magnetic anisotropy analysis: the prospect of finite strain calibration. Tectonophysics 98:327–336CrossRefGoogle Scholar
  11. Hrouda F (1973) A determination of the symmetry of the ferromagnetic mineral fabric in rocks on the basis of the magnetic susceptibility anisotropy measurements. Gerl Beitr Geophys 82:390–396Google Scholar
  12. Hrouda F (2002) Low-field variation of magnetic susceptibility and its effect on the anisotropy of magnetic susceptibility of rocks. Geophys J Int 150:715–723CrossRefGoogle Scholar
  13. Hrouda F (2002a) The use of the anisotropy of magnetic remanence in the resolution of the anisotropy of magnetic susceptibility into its ferromagnetic and paramagnetic components. Tectonophysics 347:269–281CrossRefGoogle Scholar
  14. Hrouda F (2007) Anisotropy of magnetic susceptibility of rocks in the Rayleigh Law region: modelling errors arising from linear fit to non-linear data. Studia Geophys Geod 51:423–438CrossRefGoogle Scholar
  15. Hrouda F (2009) Determination of field-independent and field-dependent components of anisotropy of susceptibility through standard AMS measurements in variable low fields I: theory. Tectonophysics 466:114–122CrossRefGoogle Scholar
  16. Hrouda F (2010) Modelling relationship between bulk susceptibility and AMS in rocks consisting of two magnetic fractions represented by ferromagnetic and paramagnetic minerals – implications for understanding magnetic fabrics in deformed rocks. J Geol Soc India 75:254–266CrossRefGoogle Scholar
  17. Hrouda F, Chlupáčová M, Mrázová Š (2006) Low-field variation of magnetic susceptibility as a tool for magnetic mineralogy of rocks. Phys Earth Planetary Inter 154:323–336CrossRefGoogle Scholar
  18. Hrouda F, Chlupáčová M, Novák JK (2002) Variations in magnetic anisotropy and opaque mineralogy along a kilometer deep profile within a vertical dyke of the syenogranite porphyry at Cínovec (Czech Republic). J Volcanol Geotherm Res 113:37–47CrossRefGoogle Scholar
  19. Hrouda F, Faryad SW, Chlupáčová M, Jeřábek P, Kratinová Z (2009a) Determination of field-independent and field-dependent components of anisotropy of susceptibility through standard AMS measurements in variable low fields II: An example from the ultramafic body and host granulitic rocks at Bory in the Moldanubian Zone of Western Moravia, Czech republic. Tectonophysics 466:123–134CrossRefGoogle Scholar
  20. Hrouda F, Faryad SW, Jeřábek P, Chlupáčová M, Vitouš P (2009b) Primary magnetic fabric in an ultramafic body (Moldanubian Zone, European Variscides) survives exhumation-related granulite-amphibolite facies metamorphism. Lithos (2008), 111:95–111CrossRefGoogle Scholar
  21. Jackson M (1991) Anisotropy of magnetic remanence: a brief review of mineralogical sources, physical origins, and geological applications, and comparison with susceptibility anisotropy. PAGEOPH 136:1–28CrossRefGoogle Scholar
  22. Jackson M, Moskowitz B, Rosenbaum J, Kissel C (1998) Field-dependence of AC susceptibility in titanomagnetites. Earth Planet Sci Lett 157:129–139CrossRefGoogle Scholar
  23. Janák F (1965) Determination of anisotropy of magnetic susceptibility of rocks. Studia Geophys Geod 9:290–301CrossRefGoogle Scholar
  24. Jelínek V (1977) The statistical theory of measuring anisotropy of magnetic susceptibility of rocks and its application. Geofyzika n.p. BrnoGoogle Scholar
  25. Jelínek V (1981) Characterization of magnetic fabric of rocks. Tectonophysics 79:T63–T67CrossRefGoogle Scholar
  26. Jelínek V (1993) Theory and measurement of the anisotropy of isothermal remanent magnetization of rocks. Travaux Geophys 37:124–134Google Scholar
  27. Ježek J, Hrouda F (2000) The Relationship bBetween the Lisle orientation tensor and the susceptibility tensor. Phys Chem Earth A 25:469–474CrossRefGoogle Scholar
  28. Ježek J, Hrouda F (2007) SUSIE: A program for inverse strain estimation from magnetic susceptibility. Comput Geosci 33:749–759CrossRefGoogle Scholar
  29. Markert H, Lehmann A (1996) Three-dimensional Rayleigh hysteresis of oriented core samples from the German Continental Deep Drilling Program: susceptibility tensor, Rayleigh tensor, three-dimensional Rayleigh law. Geophys J Int 127:201–214CrossRefGoogle Scholar
  30. Nagata T (1961) Rock magnetism. Maruzen, TokyoGoogle Scholar
  31. Néel L (1942) Theory of Rayleigh’s law of magnetization. Cahier Phys 12:1–20Google Scholar
  32. Nye JF (1957) Physical properties of crystals. Clarendon Press, OxfordGoogle Scholar
  33. Pokorný J, Suza P and Hrouda F (2004) Anisotropy of magnetic susceptibility of rocks measured in variable weak magnetic fields using the KLY-4S Kappabridge. In: Martín-Hernández F, Lüneburg CM, Aubourg C, Jackson M (eds) Magnetic fabric: methods and applications. , Special Publications, vol 238. Geological Society, London, pp 69–76Google Scholar
  34. Potter DK, Stephenson A (1988) Single-domain particles in rocks and magnetic fabric analysis. Geophys Res Lett 15:1097–1100CrossRefGoogle Scholar
  35. Raposo MIB, Ernesto M (1995) Anisotropy of magnetic susceptibility in the Ponta Grossa dyke swarm (Brazil) and its relationship with magma flow direction. Phys Earth Planetary Inter 87:183–196CrossRefGoogle Scholar
  36. Scheidegger AE (1965) On the statistics of the orientation of bedding planes, grain axes, and similar sedimentological data. US Geol Surv Prof Paper 525-C:164–167Google Scholar
  37. Stacey FD and Benerjee SK (1974) The physical principles of rock magnetism. Development in solid earth geophysics. Elsevier, Amstredam, 195 ppGoogle Scholar
  38. Stephenson A, Sadikun S, Potter DK (1986) A theoretical and experimental comparison of the anisotropies of magnetic susceptibility and remanence in rocks and minerals. Geophys J R Astron Soc 84:185–200Google Scholar
  39. Worm H-U, Clark D, Dekkers MJ (1993) Magnetic susceptibility of pyrrhotite: grain size, field and frequency dependence. Geophys J Int 114:127–137CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  1. 1.AGICO Inc.BrnoCzech Republic
  2. 2.Institute of Petrology and Structural Geology, Charles UniversityPrahaCzech Republic

Personalised recommendations

Cite chapter

Buy options