Behavior of u-channels during acquisition and demagnetization of remanence

Implications for paleomagnetic and rock magnetic measurements

Stefanie Brachfeld, Catherine Kissel, Carlo Laj, Alain Mazaud

Research output: Contribution to journalArticleResearchpeer-review

16 Citations (Scopus)

Abstract

We have examined the effects of translation speed on the acquisition and demagnetization of remanence in u-channels. The speed at which the u-channel moves through alternating and steady fields has a significant effect on the efficiency of remanence acquisition and demagnetization. Anhysteretic remanence (ARM) acquisition and alternating field (AF) demagnetization efficiency are inversely correlated with translation speed. ARM acquisition is most efficient at a track speed of 1 cm/s, whereas at higher speeds ARM reaches an apparent saturation at low peak fields and has a soft coercivity spectrum during subsequent AF demagnetization. The dependence of magnetization (acquired or removed) on translation speed through alternating or steady fields is explained by the number of alternating field half-cycles experienced as the sample is translated through the applied field and on the alternating field decay rate. At slow translation speeds a u-channel experiences a comparable number of alternating field cycles to that experienced by a stationary discrete sample. At fast translation speeds, the u-channel experiences a factor of 100 fewer alternating field cycles, and the conditions experienced by the u-channel sample can be comparable to the natural reorganization time of the magnetic moments within the sediment particles during remanence acquisition and demagnetization. At low decay rates the sample has more time in the blocking field and thus a more complete approach to equilibrium.

Original languageEnglish
Pages (from-to)1-8
Number of pages8
JournalPhysics of the Earth and Planetary Interiors
Volume145
Issue number1-4
DOIs
StatePublished - 30 Jul 2004

Fingerprint

demagnetization
remanence
magnetic measurement
acquisition
rocks
rock
cycles
decay rates
speed
coercivity
magnetization
sediments
magnetic moments
high speed
saturation
sediment

Keywords

  • Alternating field demagnetization
  • Anhysteretic remanent magnetization
  • Paleomagnetism
  • Relative paleointensity
  • Rock magnetism
  • U-Channel

Cite this

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title = "Behavior of u-channels during acquisition and demagnetization of remanence: Implications for paleomagnetic and rock magnetic measurements",
abstract = "We have examined the effects of translation speed on the acquisition and demagnetization of remanence in u-channels. The speed at which the u-channel moves through alternating and steady fields has a significant effect on the efficiency of remanence acquisition and demagnetization. Anhysteretic remanence (ARM) acquisition and alternating field (AF) demagnetization efficiency are inversely correlated with translation speed. ARM acquisition is most efficient at a track speed of 1 cm/s, whereas at higher speeds ARM reaches an apparent saturation at low peak fields and has a soft coercivity spectrum during subsequent AF demagnetization. The dependence of magnetization (acquired or removed) on translation speed through alternating or steady fields is explained by the number of alternating field half-cycles experienced as the sample is translated through the applied field and on the alternating field decay rate. At slow translation speeds a u-channel experiences a comparable number of alternating field cycles to that experienced by a stationary discrete sample. At fast translation speeds, the u-channel experiences a factor of 100 fewer alternating field cycles, and the conditions experienced by the u-channel sample can be comparable to the natural reorganization time of the magnetic moments within the sediment particles during remanence acquisition and demagnetization. At low decay rates the sample has more time in the blocking field and thus a more complete approach to equilibrium.",
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Behavior of u-channels during acquisition and demagnetization of remanence : Implications for paleomagnetic and rock magnetic measurements. / Brachfeld, Stefanie; Kissel, Catherine; Laj, Carlo; Mazaud, Alain.

In: Physics of the Earth and Planetary Interiors, Vol. 145, No. 1-4, 30.07.2004, p. 1-8.

Research output: Contribution to journalArticleResearchpeer-review

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T2 - Implications for paleomagnetic and rock magnetic measurements

AU - Brachfeld, Stefanie

AU - Kissel, Catherine

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AU - Mazaud, Alain

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