TIME-SERIES ANALYSIS OF NATURAL REMANENT MAGNETIZATION IN DEEP-SEA SEDIMENTS

Natural remanent magnetization (NRM) and saturation isothermal remanent magnetization (SIRM) of deep‐sea sediments from the equatorial Pacific and south‐western Indian Ocean were subjected to time series analysis. Three different approaches were employed to investigate the variation of geomagnetic total force. At both sites, these analyses show periodicities of 25 000 and 18 000 yr. The period of 25 000 yr, which is nearly equal to the Earth's precessional period (25 800yr), suggests that the precession plays some role in the generation of the geomagnetic field. Fluctuations of palaeo‐magnetic declination and inclination seem to have no remarkable periodicities. Copyright © 1979, Wiley Blackwell. All rights reserved