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Reliable paleomagnetic records from single-vortex iron particles
  • +3
  • Shichu Chen,
  • Thomas Berndt,
  • Wyn Williams,
  • José Augusto Devienne,
  • Lesleis Nagy,
  • Peihong Wu
Shichu Chen
Peking University

Corresponding Author:[email protected]

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Thomas Berndt
Peking University
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Wyn Williams
University of Edinburgh
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José Augusto Devienne
Peking University
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Lesleis Nagy
University of Liverpool
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Peihong Wu
Peking University
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Abstract

Paleointensity observations from meteorites provide insights into planetary formation and evolution. Meteoritic samples are usually dominated by Fe-rich kamacite, which is capable of faithfully recording the ancient dynamo activity of meteorites’ parent body. To retrieve paleointensity estimates, experimental protocols assume that samples are dominated by uniformly magnetized particles. However, most magnetic carriers observed in extraterrestrial samples are non-uniformly magnetized. This inconsistency represents a major impediment in reliably reconstructing paleointensities from meteorites. Here we present the State Group Algorithm (SGA); a micromagnetic based model capable of efficiently simulating thermoremance acquisition of magnetic particles with a single-vortex domain state. The results show that iron particles can acquire thermoremance that is linear with the external field up to ∼100 µT. Single-vortex cooling rate effects are generally weaker than those of single-domain particles, providing more accurate paleointensity estimates. A small number of particles exhibit inverse cooling rate effects, leading to underestimates in paleointensity.
09 Oct 2024Submitted to ESS Open Archive
14 Oct 2024Published in ESS Open Archive