Statistical structure of geomagnetic field reversals

Geomagnetic polarity intervals determined from the analysis of the marine magnetic field have been subjected to statistical analysis. The major finding is that the statistical structure undergoes a discontinuous change around 50 million years ago. The polarity intervals from 0 to 48 m.y. form a stationary sequence and are governed by gamma distribution, but the intervals are not independent. The polarity intervals from 56 to 72 m.y., are also stationary and are governed by gamma distribution but have different parameters. The intervals appear to be independent. The above conclusions for the period 56 to 72 m.y. are, on account of limited data, somewhat tentative. The discontinuous change in the statistical structure appears to coincide with the worldwide tectonic activity of the early Eocene.