Assessing the preservation of orbital signals across different sedimentary environments: Insights from stochastic sedimentation modeling

Orbital forcing, a primary climatic driver, imprints discernible signatures in sedimentary strata that are instrumental for elucidating climatic change mechanisms and establishing high-resolution astronomical time scales (ATS). Our research dives into sedimentology and cyclostratigraphy, tackling the longstanding enigma of how orbital signals survive in dynamic environments where sediment deposition occurs at highly variable rates. Utilizing a stochastic sedimentation model, we simulate stratigraphic records containing orbital rhythms, representative of a range of depositional settings. We show that the 405-kyr eccentricity cycle is often the most reliably preserved, and sometimes even the sole trustworthy metronome in devising ATS among various tuning strategies. This holds particularly true in environments with high energy and unsteady sedimentation, such as fluvial or deltaic settings. In contrast, environments with lower sedimentation rate variability and higher overall sedimentation rates allow for the use of shorter-period orbital parameters in astronomical tuning, thereby enhancing the temporal resolution of ATS. This study has implications not only for decoding past climate forces but also for refining the precision of ATS, contributing significantly to our understanding of Earth's geological history.