Late Quaternary depositional characteristics and environment significance of the Xibozhang section in Baoding, central Hebei Plain, China

This paper aims to ascertain the depositional paleoenvironment since the late Quaternary in the central Hebei plain. We measured the 20.74 m-deep Xibozhang section and analyzed the collected samples for grain size and optically stimulated luminescence (OSL) tests. OSL dating results indicate that the deposits were formed during 102~8.67 ka, belonging to the late Pleistocene to early Holocene. Analysis of lithology and grain size show that, the section is fluvial deposit with typical binary structure, which can be further divided into channel deposit and floodplain deposit. The channel deposits are mainly medium-coarse sand containing mica fragments, with oblique bedding. Frequency curves is characterized by positive bias bimodal with moderate to poor sorting, and the probability cumulative curves are mainly two-stage dominated by jump components. The floodplain deposit is mainly clayey silt with well-preserved shell fossils and calcareous nodules. Most frequency curves are negative bias bimodal with poor sort