Cyclostratigraphic constraints on the evolution of the Earth-Moon system over the last 650 million years

Astronomical cycles in the Earth’s orbit and axis orientation have been widely recognized to drive climatic changes that result in cyclic sediment deposition. The developing discipline of astrochronology uses these cycles to progressively refine the geological time scale. Astronomy therefore informs geology. Conversely, can the geological record provide astronomical information?

We present here the results of applying a Bayesian inversion method to estimate the Earth’s axial precession frequency in 34 high-quality cyclostratigraphic records spanning the past 650 million years. Sediment cycles record the Earth’s axial precession frequency (via climatic precession and obliquity), which is a function of the lunar distance and of the Earth’s spin rate. Through time, tidal energy dissipation progressively slows down the Earth’s rotation, transferring angular momentum to the Moon’s orbit and increasing lunar distance. Our analysis reveals that the axial precession frequency has decreased markedly in geologic time (by about 30% between 650 Ma and the present). From the estimated variation in the axial precession frequency and angular momentum conservation in the Earth-Moon-Sun system, we calculate the corresponding evolution of the length of day and lunar distance. The results indicate an interval of high tidal energy dissipation between ~300 to 200 Ma and are in general agreement with independently calculated tidal evolution models. Moreover, our analysis provides an improved determination of the past frequencies of obliquity and climatic precession for astrochronology applications.