Chaotic behaviour of the Solar System over the past 250 Ma

Earth's orbital variations are the primary control on insolation and climate. However, the astronomical solutions for planetary orbits beyond several tens of million years (Myr) ago have large uncertainties due to the chaotic behaviour of Solar System, mainly Myr-scale cycles related with gravitational interaction between Earth and Mars. Climatic cycles recorded in sediments are only archives to reconstruct the past chaotic behaviour of Solar System, yet their reliability is still debated. Here, we examined multi-Myr cycles in the Triassic-Jurassic orbitally-paced monsoon records from two different sedimentary proxies (the lake level records of the equatorial Pangea and biogenic silica burial flux of deep-sea Panthalassa) and a compiled marine carbon isotope data. Three independent results show multi-Myr cycles with similar in temporal patterns of frequency modulations, which are different from all the available numerical solutions. This finding provides not only convincing evidence for the chaotic behavior of the Solar System in the geological past, but also additional constraints on the astrophysical models of Solar System. Some of multi-Myr cycles in monsoon-related records for Mesozoic-Cenozoic could have potential to constrain the chaotic behavior of the Solar System, if we can subtract the effect of tectonic events on Myr-scale climate change.