규조분석을 이용한 화진포의 퇴적환경 복원

Abstract

Lake Hwajinpo is located on the eastern coast of Korea. This study reconstructed sedimentary environment of Hwajinpo and its surroundings and presumed sea-level changes during the Holocene using radiocarbon dating and diatom analysis from core samples. The undisturbed core samples were taken at the inner lake and the outer lake of Lake Hwajinpo, named HJP01 and HJP02 respectively. HJP01 is located at the delta margin by the tributary sedimentation. The numbers of freshwater and freshwater-brackish water species was increased gradually from the bottom to upper of the core, according to the expansion of the delta. The relative marine regression, the environmental change from high salinity environment(marie-brackish water) to low salinity(freshwater) was observed in the core. In contrast to HJP01 site, HJP02 site is affected by the sea-level change directly. According to the result of diatom analysis, the brackish lagoon environment was formed surrounding ca.4,000yrBP. However, the relative marine regression started since about 3,200yrBP because the number of marine and brackish water species reduced gradually. After then the lake environment was presumably disappeared and the HJP02 site was completely dried up since 2,500yrBP through 1,450yrBP, because the diatom frequency of this period became very poor. Since 1,450yrBP, HJP02 recovered aquatic environment, however it was separated from lake water from Lake Hwajinpo by the coastal ridge along the lake, and has continuosly deposited peat bogs till now.