Sediment is initially settled in a zero field (B=0) for ∼5 days. PDRM acquisitions occurs after a controlled field (B>0) is applied for ta≅7 days. During this time, the equilibrium magnetization, Meq, is approached. Finally, the acquired magnetization, M(ta), is allowed to decay in a zero field for a time td. The remanent magnetization during acquisition and decay phases is measured at regular time intervals.