The Loess-paleosol Stratigraphy of Daecheon Section in the West Coast of South Korea

We aim to identify the proxy data for the paleoclimate used in Chinese Loess Plateau and to clarify the origin of Korean Loess by the geochemical analysis of the sediments, such as XRF and REE. At Daecheon section of South Korea(N 36°15'50", E 126°33'56"), three sets of loess-paleosol layer are found overlaid about 2.1m thick on the gravel layer of marine terrace. The field observation such as the soil color and soil crack, and magnetic susceptibility values showed clearly the characteristics as the loess-paleosol sequence. Each layer from the top is named as L1S1, L1L2, S1, L2, S2, L3, Mn- and marine terrace layer respectively. Based on OSL ages and correlation with Dukso section in Korea(Shin, 2003), loess-paleosol sequence at Daecheon section was developed during MIS 8~3, marine terrace layer during MIS9. A-CN-K or A-CNK-FM diagram shows the characteristics between Korean and Chinese loess-paleosol clearly. Chinese samples are in the linear direction, and Korean samples are separated and coexisted in a different part. Marine samples(DC3 180, 210) are also isolated from loess at Daecheon section. This direction could be regarded as weathering trend originated from the different climate condition(or climatic gradient) between Korea and China. MAT and MAP are 12.1° and 1,200mm on the study area and 9.2°, 623mm at Luochuan, the most famous region in Chinese Loess Plateau. MAP is especially responsible for element composition. It means, the composition of loess could be changed easily under the special climate condition after accumulation. Condrite-normalized REE patterns, (La/Yb)N(8.88~14.01) and Ce anomalies show a similar origin to China, but differences by more precipitation in Korea than Chinese Loess Plateau.