뢰스-고토양 연속층의 식물규소체 분석으로 복원한 Pleistocene 후기 거창분지 환경 변화

Abstract

This study aims to analyze phytolith assemblages obtained from the Geochang section in South Korea. The assemblages consisted of a river sediment (MIS 7), loess-paleosol sequences (MIS 6 to 2), and a cultivated layer from bottom to top. We reconstructed the environmental change during the late Quaternary and investigated the weathering characteristics of phytoliths and applicability of climatic indices. The section was divided into the Geochang Phytolith Zones (GPZs) I to IV based on sedimentary facies, age dating, mean grain size, magnetic susceptibility value and absolute quantity of phytoliths. The total sum of phytoliths output from the Holocene (GPZ IV) was much greater than that from the loess-paleosol sequences or river sediment (GPZ III to I). Moreover, the absolute quantities of phytoliths from the loess and paleosol layers indicated a variation similar to those in the magnetic susceptibility, suggesting a close connection between the quantities and climatic conditions. Each layer also showed distinct weathering characteristics in the phytoliths. Although detailed information on the paleoclimatic variations in the Geochang area cannot be extracted by phytoliths analysis alone due to the low quantities, the different climatic conditions between the glacial and interglacial periods can potentially be inferred from the absolute quantities of phytoliths extracted from the loess and paleosol layers.