Reappraising the Elatina series: Solar dynamo clocking and inference of orbital periods

TL;DR

This study reexamines 680-million-year-old sedimentary records revealing stable solar and orbital cycles, employing a solar dynamo model to infer planetary orbital periods and angular momentum changes over geological timescales.

Contribution

It introduces a novel application of a solar dynamo synchronization model to interpret ancient sedimentary cycles and infer planetary orbital variations from geological data.

Findings

Identified a stable 12-year cycle close to the Schwabe cycle.

Detected a 314-year Elatina cycle linked to orbital influences.

Estimated small but plausible angular momentum changes in Jupiter and Earth.

Abstract

We reconsider the 680 million year old Elatina series of sedimentary laminae from South Australia that show a remarkably stable periodicity with a main period of around 12 years, which is close to the Schwabe cycle, and a second period of 314 years that has been coined Elatina cycle. By analyzing the residuals of the series' minima from a linear trend, and deriving Dicke's ratio, we first show that the series exhibits a high degree of phase stability, except one single break point which may indicate a 90{\deg} phase jump. We discuss the data in terms of a recently developed synchronization model of the solar dynamo. This model is then employed to infer those orbital periods of Venus, Earth, Jupiter and Saturn that would be required to jointly explain the moderately changed Schwabe cycle, and the Elatina cycle when interpreted as a prolonged Suess-de Vries cycle. Assuming pairwise conservations of the sum of the angular momenta of Jupiter/Saturn and Venus/Earth, respectively, we find solutions of the underlying inverse problem which amount to approximately 1 percent angular momentum increase of Jupiter and a 0.005 per cent angular momentum increase of Earth. The plausibility of such changes over a period of seven hundred million years is discussed in light of solar system dynamics.