332-3 Evidence for Solar System chaos in the Late Cretaceous and its temporal coupling with Earth System perturbations

Abstract:

Planetary orbits evolve under gravitational interactions among Solar System bodies, producing cyclic variations in Earth’s insolation that can be recorded by sedimentary strata. These astronomical cycles provide a fundamental framework for geological timekeeping and for understanding long-term climate change. However, because chaotic diffusion limits the reliability of numerical orbital solutions beyond approximately 60 Myr, the behavior of ancient planetary dynamics remains empirically constrained only by geological archives. Previous geological evidence for Mesozoic orbital chaos has been based mainly on individual records, leaving uncertain whether such chaotic transitions were expressed coherently at a global scale and how they coincided with long-term climate evolution. Here we show that seven globally distributed Late Cretaceous sections record coherent million-year–scale orbital signals over an interval of 11 Myr. All sections display a remarkably consistent expression of the (g₄–g₃) secular modulation, but these records diverge from existing astronomical solutions and instead closely match a combined La04–La10c model. This agreement indicates that the chaotic transition was not a local stratigraphic artifact but a globally expressed feature of Solar System dynamics. The timing of this transition overlaps with global surface-temperature maxima followed by cooling, supporting the interpretation that chaotic changes in orbital architecture may have contributed to the reorganization of long-term climate evolution. These results strengthen the geological evidence for Solar System chaos and provide a globally distributed framework for evaluating its possible role in Earth’s long-term climate variability.

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