'Clean' spectral analysis of long-term sea-level changes

A new ‘clean’ spectral technique has been applied, for the first time, to analyse a record of long-term sea-level fluctuation during the last 200 million year (Myr). The technique is based on a one dimensional complex deconvolution algorithm and removes the effects of the data sampling as well as the artifacts arising from the choice of data window. The analysis reveals a dominant periodicity of 33 Myr in the sea-level variations. This periodicity compares well with the known half-period of the Sun's oscillation perpendicular to the galactic plane. Interestingly, a 33 Myr periodicity can also be correlated with the reported mass extinction cycles and other geological periodicities. The results suggest galactic forcing as a possible driving mechanism for quasi-periodic terrestrial processes.