Tropical forcing of midlatitude terrestrial hydroclimate during the Late Cretaceous

Abstract During the ice-free Cretaceous, the tropics have been proposed as key drivers of global climate, yet direct mid- to high-latitude evidence remains absent. Here, we present centennial-resolution geochemical records of hydroclimatic variability from early Campanian (83.62–83.14 Ma) midlatitude lacustrine successions. The records exhibit significant sub-precessional cycles at 10–12 k.y. and 5–5.4 k.y., and other millennial-scale cycles, primarily at ~3.6 k.y., ~2.6–2.5 k.y., and ~2.3 k.y. High-precision chronology, phase locking of different proxies, and eccentricity-modulated amplitudes identify these sub-precessional signals as semi- and quarter-precession cycles. As these signals are most consistent with a tropical origin, their footprints in midlatitude hydroclimate records highlight the tropical control on climate during this greenhouse interval. Such low- to high-latitude teleconnection would provide efficient poleward heat and moisture transport, helping to reconcile the anomalously warm Cretaceous poles under a weak meridional temperature gradient. We further show that the ~3.6-k.y. and ~2.6–2.5 k.y. cycles arise from semi- and quarter-precession cycles via combination of tones and harmonics, whereas the ~2.3 k.y. cycles are most likely linked to solar activity, underscoring their persistence throughout geological history.