Maximum Entropy Spectral Analysis of the geological time series of the oxygen isotope record from deep-sea cores

A Maximum Entropy Spectral Analysis of the geological time series of the oxygen isotope 18 for the last 782,000 years showed 98,000 years as the most prominent periodicity, followed by 40,000 years of less than half the amplitude and still smaller peaks at 24,000, 67,000, 84,000, 107,000 and 786,000 years. Among the astronomical parameters, only eccentricity showed a similar periodicity viz. 96,000 years. Obliquity had a prominent periodicity at 41,000 years which was reflected in the oxygen isotope series also. Corresponding to the bimodal precession peaks (23,000 and 19,000 years), the oxygen isotope series showed a peak at 24,000 years and smaller peaks at 22,000 and 19,000 years. Our results compare well with those obtained byThomson (1990) with a more sophisticated method.