Fine et al. Hematite is unimportant for the magnetic record of climate change, however, having negligible magnetic susceptibility relative to the ferrimagnetic minerals.
Disagreement exists, however, about the mineral type of the ultrafine pedogenic magnetic grains.
The dominance of magnetite in paleosols is indicated, primarily using thermomagnetic techniques, by Heller et al. They suggested that size-induced phase transitions in Fe O energetically favors maghemite for certain ultrafine grain sizes between 100 and 300 Angstroms. If so, a population of maghemite grains in this size range would possess both SP and SD behavior.