Figure F37. Lowrie-Fuller tests using results from anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) experiments. The tests indicate smaller magnetic particle size (single domain to pseudosingle domain) for Samples 206-1256B-3H-3, 121 cm, and 5H-3, 25 cm (the two upper plots), as indicated by the proportion of ARM that decays relative to that of the IRM. For these two samples, the intensity decay of the ARM and IRM is similar from 0-mT demagnetization down to their respective median destructive fields at ~20-35 mT. For Samples 206-1256B-7H-3, 81 cm, 9H-3, 55 cm, and 11H-3, 91 cm, the IRM is more resistant to demagnetization than the ARM over most of the coercivity spectrum, which indicates larger grain sizes (pseudosingle domain and multidomain). Sample 206-1256B-13H-3, 62 cm, is dominated by noise, and the Lowrie-Fuller test does not provide useful grain size information.

Figure F37. Lowrie-Fuller tests using results from anhysteretic remanent magnetization (ARM) and isothermal remanent magnetization (IRM) experiments. The tests indicate smaller magnetic particle size (single domain to pseudosingle domain) for Samples 206-1256B-3H-3, 121 cm, and 5H-3, 25 cm (the two upper plots), as indicated by the proportion of ARM that decays relative to that of the IRM. For these two samples, the intensity decay of the ARM and IRM is similar from 0-mT demagnetization down to their respective median destructive fields at ~20-35 mT. For Samples 206-1256B-7H-3, 81 cm, 9H-3, 55 cm, and 11H-3, 91 cm, the IRM is more resistant to demagnetization than the ARM over most of the coercivity spectrum, which indicates larger grain sizes (pseudosingle domain and multidomain). Sample 206-1256B-13H-3, 62 cm, is dominated by noise, and the Lowrie-Fuller test does not provide useful grain size information.