Late Holocene sea level changes inferred from the traditional salt (Jayeom) production of the Gomso Bay, Korea

The traditional salt of Korea is the boiled salt obtained by boiling the sea water. In the Gomso bay around Buan and Gochang areas, people made a salt field on tidal flat sediments to obtain dense salt water. At this time, the location of the salt field would be on the most upper part of the tidal flat where the sea water comes in only at the time of spring tides. Based on the records of ancient documents, the locations of the salt field in the area of Gumdang village of the Gomso bay have been changed during the historical period. In the early 1900s, the salt fields were in front of Gumdang village. Several tide embankments around the Gomso Bay including Byokgolje (Gimje), Nullje (Joengeup), and Hwangdeungje (Iksan) were believed to be build in around AD 300-500. Based on this, the salt field sites would have been similar in about AD 500. In around AD 1500, Sinjeung Donggukyeojiseungram ((sic), 1530) reported the locations of the salt field were moved about 800 m toward the sea. However, the records from Taekliji ((sic), 1751) and County map ((sic), 1872) suggest that the salt field were moved back on the recent positions. The salt field positions of the 1500s and the 1800s differ and imply that the sea level positions have been changed. Such sea level changes inferred from the historical records closely coincides with regional and global sea level variations.