Figure F69. Examples of progressive AF demagnetization up to 50 mT of basement archive halves. A. Section 183-1142A-10R-3 at 65 cm from basement Unit 6. The magnetization has a MDF of 15 mT and a single-component magnetization. B. Section 183-1142A-5R-2 at 60 cm from basement Unit 3. The magnetization has a very high MDF. J₀ is the magnetization intensity before AF treatment.