Late Holocene Shallow Marine Sand Sheet in the Haeundae Coast, Korea

Abstract

The Haeundae coast is located in the southeastern corner of the Korean Peninsula without any significant riverine influences. Haeundae Beach, stretching in the E-W direction, is included in this area. To investigate the distribution of sand deposits herein, shallow seismic profiling was carried out and drill cores obtained previously were reanalyzed sedimentologically. The cores show that the uppermost sands are underlain by gravelly deposits which lie on weathered soils or the bedrock. Based on the correlation with the drill cores, seismic profiles illuminate the Holocene transgressive sand sheets that occur in water of 10-15 m within 1 km of Haeundae Beach. Theses sand sheets are therefore considered as the remnants of antecedent beach deposits. In contrast, the present-day beach deposits are outlined mostly in the surf zone except for an elongate portion. It extends offshore to the 13-m water depth from the westernmost surf zone. This offshore-directed limb is interpreted to be a major sink of the suspended sand from Haeundae Beach in concert with the established surf-flow system. These preliminary sedimentological results shed light on the whereabouts of the sands eroded from Haeundae Beach. In addition, the differentiation of the origin between the sand deposits may contribute much to engineering applications such as sand transport modelling.