Figure 5. AF and thermal demagnetization results characteristic of some of the better basalt samples from Site 1001. Thermal demagnetization results for Sample 165-1001A-53R-1, 2 cm (left three plots), show that the magnetic mineral carrying the ChRM has an unblocking temperature concentrated between 420°C and 570°C. The steep drill-string overprint is removed by ~360°C with the shallow ChRM direction remaining. AF demagnetization results for Sample 165-1001A-54R-3, 126 cm, shows that the magnetic mineral carrying the ChRM has a medium coercivity whereas the drill-string overprint has a low coercivity. This allows the drill-string overprint to be removed by about 15-20 mT. See Figure 2 caption for diagram descriptions.