Provenance and Transport Mechanisms of Fine-Grained Sediments in the Hupo Basin, Offshore East Coast of Korea

Thirty-three surface sediment samples were collected from the Hupo Basin including Hupo Bank, located offshore along the East Coast of Korea, to investigate the provenance of fine-grained sediments using geochemical elements, particularly focused on REEs compositions. Cluster analysis of the surface sediments identified three distinct groups: (1) the inner offshore area of the northwestern Hupo Bank, (2) the area extending from the inner offshore of the southwestern Hupo Basin to the eastern slope of the Hupo Bank, and (3) a single sediment deposit on the eastern slope of the Hupo Bank.

Additionally, the sediments from the southwestern Hupo Basin to the eastern slope of the Hupo Bank were further classified into two subgroups based on their UCC-normalized (Upper Continental Crust-normalized) REE patterns. A comprehensive analysis of the UCC-normalized REE patterns, combined with satellite imagery, suggested that most of the sediments on the northwestern Hupo Bank were predominantly supplied by small nearby streams during typhoon seasons. However, some sediments covered on southern Hupo Basin were likely transported from the southern area via the East Korea Warm Current during the heavy rainy season.