Stratigraphic heterogeneity in the Yangtze River subaqueous delta revealed by chronological and mineral magnetic approaches

Delta deposits show large spatial heterogeneity in terms of depositional rate and age, which is critical to the study of delta erosion in response to the declining fluvial sediment load observed at many river mouths in the world. In this study, we demonstrate the magnetic susceptibility (χ) as a rough indicator to reveal age variations and stratigraphic heterogeneity in the Yangtze River subaqueous delta. Ages of three short sediment cores (210Pb, 137Cs, and optically stimulated luminescence (OSL) dating. In addition, depth variation of χ, which is influenced by post-depositional diagenesis and hence age, was used to roughly estimate sediment ages among the cores in a quick way. The profiles of 210Pb, 137Cs, and OSL results indicate the spatial variability of ages, ranging from the last 100 years to more than 2000 years. Cores at shallow water depths are younger than those from deeper sites. Modern deposits (i.e.