Figure F10. Plots of alternating field demagnetization of natural remanent magnetization (NRM), anhysteretic remanent magnetization (ARM), and isothermal remanent magnetization (IRM) and of the acquisition of IRM plot summarizing the magnetic characteristics of the analyzed samples. The acquisition of IRM illustrated is consistent with the presence of a cubic phase, and the demagnetization of NRM demonstrates that the intensity is above the noise limit of the instrument. SIRM 1, SIRM 2, and SIRM 3 were measured at ~24-hr intervals. The decrease in saturation isothermal remanent magnetization (SIRM) is attributed to the destruction of a ferromagnetic phase, of which greigite is the most likely candidate. The ratio of IRM:ARM is indicative of single-domain behavior.