AGE AND RATE OF ACCRETION OF IRON-MANGANESE NODULES

Abstract

We studied the paleomagnetic properties of iron-manganese crusts and nodules in the Pacific Ocean. Study of changes in the polarity of the remanent magnetization vector in nodule section provided information on the age and rate of sedimentation in individual intervals of ore material. Crusts and nodules collected with drag nets and bottom grabs were studied aboard ship. The study shows that the paleomagnetic method can be used to define the polarity of the geomagnetic field and its changes in a continuous section of an iron-manganese nodule or crust and to determine the length of deposition (accretion) of the ore material and thus its age. The development of nodules and crusts in different areas of the Pacific Ocean apparently occurred at different times, depending on local conditions at the bottom.