High-resolution Chronology of Humic Soil and Peat Layer Established by Tephra Layers and Radiocarbon Dates

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Radiocarbon dates for soil and peat layers are seemed to be not reliable because of a suspicious of closed system. However, these samples are very useful for reconstructing paleo-environmental change. This study is considered by not only radiocarbon dates but also vertical change of carbon and nitrogen contents and deposit density. We try to distinguish deposition and accumulation of organic material, and establish interpretation of radiocarbon dates for these deposits in high-resolution.Subjects of investigation in this study are not only eruptive history of volcano but also glacier variation and sea level changes. Buried soil in and around Mayon Volcano (Philippines), Adak Island (USA), Ulleung Island (South Korea), Hakone Volcano, Unzen Volcano and Kirishima Volcano aredatedwithacceleratormassspectrometry(AMS).Theseeruptivehistorieshavebeen refined. Identification of bubble-wall type glass shards is very important for recognition of deposition age of widespread tephra at soil and peat sections. Because radiocarbon dates can be determined by comparing with age of widespread tephra. Radiocarbon dates from alluvial deposits in Kumamoto plane and Rarotonga Island (Cook Islands) reveal changes in sea level and coastal environments. Glacier variation in Kyrgyz Republic is also determined. Consequently, soil and peat material is widely applicable for chronological studies.