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.