Intensification of Northern Hemisphere Glaciation Triggered the Red Clay to Loess‐Paleosol Shift on the Chinese Loess Plateau 2.7 Million Years Ago

Abstract Widespread aeolian loess‐paleosol and red clay sediments on the Chinese Loess Plateau (CLP) provide a globally unique terrestrial archive of Neogene–Quaternary climate. However, the timing and associated mechanisms of red clay to loess‐paleosol shift remain debated. Here we present new magnetostratigraphic and environmental magnetic results from the Baode section, northeastern CLP. Magnetostratigraphic result demonstrates that this section spans from the upper Gilbert to lower Matuyama Chrons (3.6–2.0 Ma). Red clay shifted to loess‐paleosol sequence at ∼2.7 Ma, synchronous with the intensification of Northern Hemisphere glaciation (iNHG). Rock magnetic data indicate dominance of fine pedogenic magnetic grains, with higher concentrations in red clay. The continuous magnetic susceptibility record suggests decreases in pedogenic magnetic population and precipitation at ∼2.7 Ma. We propose that ice‐sheet expansion across the iNHG, coupled with declining CO2, triggered the onset of loess‐paleosol accumulation on the CLP by suppressing Asian summer monsoon while enhancing winter monsoon circulation and inland aridity.