Mega Geocycles: Echoes of Astronomical Events

We examine here the latest available episodic and continuous records of long-term geo-hydro-bio-chemical processes using the non-parametric and modern spectral approaches. These analyses confirm the earlier findings of a 33 ± 3 million years (Myr) periodicity and reinforce that mega geo-bio-atmosphenc processes are cyclic in nature. Interestingly, six major extinction events coincide well with low phosphorous bunal rate (PBR) indicating that complex geochemical oscillations, probably caused by astronomically induced impact events, may have precipitated ocean productivity crisis leading to the biological upheaval in the earth's history. The present study combined with earlier evidence of a periodicity in the impact cratering record may provide a significant constraint on any theoretical framework attempting to unify terrestrial observations in widely different fields.