제주도 하논분화구 퇴적물에 대한 다양한 프록시 연구: 과거 3만 5천년간의 고기후 변동성에 대한 함의

Abstract

The inorganic and organic proxies were investigated in the Hanon paleo-maar sediment, Jeju Island of Korea to understand paleoclimate variabilities since the last 35 kyr. Based on the major element concentration, and its variations in Al/Ti, Al/Th showed stratigraphic difference between lower and upper part, and suggesting that sediment provenance and sources are associated with paleo-environmental changes in study area. CIA, which indicating chemical weathering of source materials, also shows continuous changing with two breaking points at 14. ka and 3.0 ka. Combining with inorganic and organic proxies, the core column stratigraphy was divided into three units, namely from the bottom to 14.5 ka (Unit I), from14.5 ka to 3.0 ka (Unit II), and from 3.0 ka to the core top (Unit III), respectively. Various organic proxies were measured to track the paleoclimatic variations, and compared with inorganic data. The TOC (%), TN (%), and their &#61540 13Corg and &#61540 15Norg show specific excursion. In particular, &#61540 13Corg showed marked fluctuation from -17.31‰ to -28.68‰, suggesting different organic carbon sources. A relatively narrow range of variation in &#61540 13Corg wasobserved in Unit III, and drastic changes in &#61540 13Corg were observed from Unit II to Unit I. This may indicate a mixture of C3 and C4 plants in Unit III, and drastic changes from terrestrial C4 in Unit II to C3 plants in Unit I. T, Al/Th showed stratigraphic difference between lower and upper part, and suggesting that sediment provenance and sources are associated with paleo-environmental changes in study area. CIA, which indicating chemical weathering of source materials, also shows continuous changing with two breaking points at 14. ka and 3.0 ka. Combining with inorganic and organic proxies, the core column stratigraphy was divided into three units, namely from the bottom to 14.5 ka (Unit I), from14.5 ka to 3.0 ka (Unit II), and from 3.0 ka to the core top (Unit III), respectively. Various organic proxies were measured to track the paleoclimatic variations, and compared with inorganic data. The TOC (%), TN (%), and their &#61540 13Corg and &#61540 15Norg show specific excursion. In particular, &#61540 13Corg showed marked fluctuation from -17.31‰ to -28.68‰, suggesting different organic carbon sources. A relatively narrow range of variation in &#61540 13Corg wasobserved in Unit III, and drastic changes in &#61540 13Corg were observed from Unit II to Unit I. This may indicate a mixture of C3 and C4 plants in Unit III, and drastic changes from terrestrial C4 in Unit II to C3 plants in Unit I. T