Orbital-scale climate forcing of atmospheric dust flux in the Middle Jurassic

Atmospheric dust fluxes are influenced by both human activities and natural climate variability, making it difficult to isolate climate-driven dust changes under modern warming. The Middle Jurassic greenhouse world provides a natural “experiment” to examine orbital-scale dust dynamics. Here, we reconstructed two high-resolution dust deposition records from mid- to high-latitude Middle Jurassic peatlands in China, using integrated petrographic, geochemical, palynological, isotopic, geochronological, and climate-model analyses. Our records reveal that the Junggar and Ordos basins hosted Aalenian ombrotrophic peatlands, with mineral matter primarily derived from atmospheric fallout, yielding atmospheric dust fluxes of 0.76–6.73 g m−2 a−1 and 1.53–27.36 g m−2 a−1, respectively. Dust fluxes are significantly linked to the hydrological cycle paced by astronomical forcing: Within published astrochronologic frameworks, humid intervals and reduced dust accumulation covary at timescales corresponding to ~405 kyr eccentricity and ~20 kyr precession. We conclude that Middle Jurassic atmospheric dust flux was primarily controlled by orbitally driven precipitation changes.