East Asian monsoon dynamics revealed by calcified root cells from a loess paleosol sequence in Northern China

Abstract The East Asian monsoon is a key component of the global climate system; our understanding of its long-term variability and seasonal dynamics remains incomplete. Here we evaluate calcified root cells (CRCs) as a novel paleoenvironmental proxy. We apply this approach to the Fanshan loess–paleosol sequence, northeast China, on the northern margins of East Asian monsoon influence. We present the first continuous down-profile record of CRC concentrations together with carbonates, stable isotopes (δ 1 ⁸O carb , δ 13 C carb ), and organic matter (δ 13 C org ) and compare these with grain-size and stratigraphic indicators. CRC concentrations correlate with glacial–interglacial variability: high concentrations within paleosol reflect enhanced vegetation and moisture availability, and low values within primary loess units reflect colder, drier conditions. The estimations of δ 1 ⁸O values of precipitation during the Marine Isotope Stage 5 (MIS 5) indicate an intensification of the monsoon rainfall as compared with present-day scenarios. The δ 13 C carb values are unusually low, which is attributed to kinetic isotope effects, thereby suggesting that CRC formation occurs under quasi-closed conditions dominated by soil organic matter respiration. Internal isotopic variability and CRC concentrations within the MIS 5 paleosol point to multiple episodes of pedogenesis. Our results demonstrate the potential of CRCs to record both long-term monsoon variability and short-term hydroclimatic seasonality, informing past East Asian monsoon dynamics.