Lithological characteristics and Quaternary stratigraphic classification of the BZK1 drill core in Tongling in the Yangtze River alluvial plain

The stratigraphic classification of the Quaternary strata in the Yangtze River alluvial plain provides a fundamental basis for reconstructing the evolution of the Quaternary environment and serves as an effective standard for calibrating reflection layers and interpreting shallow seismic profiles. It also provides a basis for studies of active urban faults and seismic hazard assessments. In this study, we examined the lithology, color, material composition, sedimentary structures, and other characteristics of the 78 m thick Quaternary succession from Liqiao Village, Xilian Town, Yi’an District, Tongling City, China using the BZK1 drill core. Based on the detailed stratigraphic subdivision, a Quaternary age framework for the BZK1 core was established using a combination of optically stimulated luminescence and electron spin resonance dating techniques. Grain size analysis was conducted to investigate the regional sedimentary environment. The BZK1 core recorwds, from bottom to top, early Middle Pleistocene alluvial deposits (56.7～ 76.2 m), Late Pleistocene fluvial deposits (35.0～ 56.7 m), and Holocene floodplain deposits (0～ 35.0 m), but lacks deposits from the Early Pleistocene and the Middle to Late Middle Pleistocene. The establishment of the Quaternary stratigraphic framework for the BZK1 drill core provides a reliable geological reference for active fault detection, artificial seismic exploration, and integrated borehole profile interpretation in Tongling City. It also offers a valuable basis for regional Quaternary stratigraphic correlation, chronostratigraphic subdivision, and the reconstruction of the sedimentary environmental evolution in the Yangtze River alluvial plain.