Analysis of the evolution of ancient environments in plain areas based on surface substrate characteristics

Investigation of black soil substrate is fundamental for its scientific conservation. Current pilot studies in multiple Chinese regions have yet to clarify substrate characteristics and paleoenvironmental reconstruction. The Liaohe Plain, a key black soil area and grain-producing region with active Cenozoic tectonics, was selected for this study. Focusing on the DTZK01 borehole in Liaoning’s Dengta City, we systematically analyzed substrate types, grain size, geochemical elements, and clay minerals using drilling, sedimentology, and geochemical methods. Results show the area is primarily river alluvium with loam and fine sand interbeds. Integrated analysis reveals that the borehole records a complete Holocene sedimentary response in the Taizi River Basin, reflecting “tectonic stability, event disturbance, and environmental reset.” Regional tectonics-controlled material supply, while global climate fluctuations dominated sedimentary redox changes. This study provides a typical case for analyzing the “source-sink” system in continental micro-fault plains, enhances understanding of clay minerals and geochemical indicators in paleoenvironmental reconstruction, and offers scientific guidance for regional black soil formation research and conservation practices.