Detection of Half‐Precessional Cycles in Late Miocene Lacustrine Sediments From Arid Central Asia

Orbital forcing is a key driver of Central Asian hydroclimate variability, yet the expression and mechanisms of the half‐precession cycle remain poorly understood in mid‐latitude terrestrial records. Here we present high‐resolution (millennial‐scale) late Miocene (~8230–8155 ka) magnetic records from lacustrine sediments in the Qaidam Basin. Integrated analysis demonstrates that magnetic parameters (χ lf , χ fd , χ fd /HIRM) provide robust proxies for chemical weathering and precipitation variability, evidenced by strong covariation between χ lf and χ fd and between χ fd /HIRM and Rb/Sr. Spectral analysis reveals a significant ~10 kyr periodicity, indicating half‐precession forcing on the basin's hydroclimate during the late Miocene. We attribute this cyclicity to alternating precipitation regimes: East Asian summer monsoon dominance during Northern Hemisphere summer perihelion and winter precipitation dominance 10 kyr later during Southern Hemisphere summer perihelion or Northern Hemisphere winter perihelion. These findings provide robust terrestrial evidence for half‐precession cyclicity in mid‐latitude Asia, advancing understanding of suborbital‐scale continental climate dynamics.