From loess to deep-time red clays: magneto-cyclostratigraphy reveals orbital pacing in East Asian dust archives back to ~60 Ma

Eolian red clays provide one of the few terrestrial archives that can track East Asian dust transport and hydroclimate variability beyond the Quaternary loess–paleosol sequence. Over the past decades, a growing body of magnetostratigraphic and cyclostratigraphic work has steadily pushed the upper age limit of astrochronologically resolved eolian red-clay records from the familiar ~3 Ma interval on the Chinese Loess Plateau to much older Cenozoic time slices. Here we synthesize this stepwise extension and highlight how environmental magnetism has been central to establishing an orbital-scale stratigraphic framework across a wide range of source–sink settings.

On the Loess Plateau, orbital-scale variability is well expressed in magnetic susceptibility and related rock-magnetic parameters, enabling robust dating over the late Neogene (~8 Ma) and, in the western Plateau, into the early Miocene (>20 Ma). Subsequent discoveries farther west expanded the record dramatically: red-clay successions near the eastern margin of the Tibetan Plateau (Altun region) preserve orbitally paced variability back to ~50 Ma, while sections along the northern Junggar Basin extend to ~25 Ma. In the eastern Erlian Basin (Inner Mongolia), continuous fine-grained red clays document cyclicity reaching at least ~48 Ma. Most recently, even older Cenozoic eolian red-clay sequences (~60 Ma) have been identified by us in the Qinling region, suggesting that dust-bearing winds and low-frequency hydroclimate pacing were established early in the Cenozoic and remained persistent across shifting paleogeography and boundary conditions.

Across these regions, magnetic susceptibility and complementary rock-magnetic proxies consistently capture astronomical forcing, with prominent long-period eccentricity and obliquity modulation embedded within precession-scale variability, despite clear differences in depositional setting, distance to desert sources, and post-depositional alteration. Treating the Cenozoic red-clay belt as a spatially distributed “network” of archives allows us to (i) test the reproducibility and phase stability of orbital signals across basins, (ii) evaluate how dust supply and pedogenic processes filter orbital forcing, and (iii) refine Cenozoic terrestrial timescales where independent radiometric constraints are limited. This synthesis shows that Cenozoic eolian red clays, when anchored by magnetostratigraphy and analyzed with cyclostratigraphy, can provide a coherent astrochronological framework from ~3 to ~60 Ma and open a path to reconstruct long-term East Asian dust–monsoon evolution on orbital timescales.