Work

Climate-driven transition from pedogenic stability to depositional dominance in Northeast China black soils: Watershed-scale stratigraphic correlations and high-resolution geochemical evidence from a representative core

Year: 2026

Type: article

Abstract: The transition between black soil formation and burial is critical for understanding how surface systems in monsoon marginal zones respond to climate change. However, the dominant controlling factors remain debated. This study focuses on the Alun River Basin in the northern Northeast China black soil region. We combined basin-scale stratigraphic correlation from 26 boreholes with high-density core sampling (∼5 cm intervals), including geochemical proxies (CIA, PIA, CIW, WIP, BWI, elemental ratios), organic carbon (Orgc), and grain-size end-member analysis. In addition, 161 published chronological datasets were compiled to reconstruct the dynamic relationship between pedogenesis and sedimentary processes during black soil formation and burial. Buried black soils are widely distributed across different geomorphic units and show consistent stratigraphic characteristics, with enrichment in the fine-grained end-member EM1. Weathering indices and organic carbon increase synchronously, indicating a basin-scale pedogenesis-dominated stage. This stable soil-forming phase corresponds closely to the Bølling–Allerød warm period (14.8–12.6 ka BP). At the top of the buried black soil, EM3, median grain size (Md), and Zr/Ti ratios increase markedly, while grain-size distributions shift to a multimodal pattern. In contrast, CIA, PIA, and OrgC decrease simultaneously. These changes indicate strengthened depositional dynamics and weakened pedogenesis, with pedogenic intensity decoupled from regional effective moisture. This transition appears to correspond to the Younger Dryas (YD) event, suggesting that enhanced transport of Okhotsk cold air may have acted as a key driver of the shift from stable pedogenesis to deposition-dominated conditions. These findings highlight the high sensitivity of surface processes in monsoon marginal zones to millennial-scale climate perturbations and provide new insights into the environmental vulnerability of black soil systems.

Source: CATENA

DOI: 10.1016/j.catena.2026.110637