Figure F14. Plots of demagnetization of natural remanent magnetization (NRM), anhysteretic remanent magnetization (ARM), and isothermal remanent magnetization (IRM), and of the acquisition of IRM (IRM A). The plots summarize the magnetic characteristics of the samples. Closed symbols represent Core 182-1128B-3H-2, and open symbols represent Core 182-1128B-13H-2. The ratios of ARM:IRM for the shallower Core 182-1128B-3H-2 are indicative of single-domain behavior and suggest a magnetotactic origin of the magnetite. The lower ARM:IRM ratio for Core 182-1128B-13H-2 implies less single-domain (bacterial) magnetite, suggesting that it suffers dissolution with increasing depth.