Milankovitch Forcing and Nonlinear Climate Variability during the Late Givetian (Appalachian Basin, New York, USA)

Abstract. Astronomical forcing is a major driver of Earth's climate variability, yet the linear and nonlinear climate responses to this forcing under warmer-than-present conditions remain poorly constrained. We use cyclostratigraphy of the Sherburne Formation, a Givetian record from the Appalachian Basin, to characterize Milankovitch cyclicity and evaluate the complex climatic behavior inferred from the sedimentary record. A new cyclostratigraphic age model refines the timing of the regional Fir Tree, Hubbard Quarry and Lodi events and places the onset of the global Frasnes Crisis (represented by the regional Lodi Event) into an astronomically calibrated framework. Our results reveal precession-eccentricity-paced detrital influx, obliquity amplification, precession-obliquity interference patterns, half-precessional cyclicity, and nonlinear climate-sediment dynamics. These findings show how pantropical late Givetian climate variability is shaped by high- and low-latitude climatic and hydrologic teleconnections and highlight the sensitivity of Devonian climate to orbital variability.