Sediment textural characteristics and spatial variability of embayed sandy beaches in the west Guangdong

Abstract The grain size analysis has been widely used to characterize or distinguish sedimentary environments, identify transport patterns and infer sediment transport directions. However, what valuable information can sediment grain size analysis provide within the modern morphodynamic framework? This paper studied the structural characteristics and spatial variability of intertidal sediments for twelve embayed sandy beaches in the west Guangdong and attempted to answer this question. The results indicated that these beaches were mainly composed of fine- or medium-grained, moderately-well sorted, nearly symmetrical and mesokurtic intertidal sediments. It was found that the cumulative probability curve was not necessarily an effective method to distinguish longshore dynamic environments, and the bivariate scatter plots between grain size parameters cannot differentiate between the upper and lower intertidal sedimentary environments. The mean sizes of the intertidal sediments were significantly correlated with the intertidal gradients, but not significantly correlated with the deep-water wave heights. The mean sizes from the upper intertidal sediments were found to be an important indicator for most of the embayed sandy beaches, reflecting the longshore variation of modern hydrodynamics. In addition, it was highlighted for the role of sediment source and various past processes, which largely determined the basic characteristics of the studied beach sediments.