Paleoenvironmental Analyses of the Buried Peat Deposit during the mid-Holocene at the Desaki Coast in Tamano City, Okayama Prefecture, Weatern Japan
松下 まり子 Research Institute for Higher Education, Kobe University
佐藤 裕司 Institute of Natural and Environmental Sciences, University of Hyogo
鈴木 茂之 Department of Earth Sciences, Faculty of Science, Okayama University
行基 幸一 Daiken Kogyo Co Ltd.
百原 新 Department of Environmental Science, Faculty of Horiculture, Chiba University
植田 弥生 Paleo Labo Co Ltd.
加藤 茂弘 Museum of Nature and Human Activities, Hyogo
前田 保夫 Institute of Natural and Environmental Sciences, University of Hyogo
The buried peat deposit was foud in the sand beach on the Desaki coast (Tamano City, Okayama Prefecture), the northeastern coast of Seto Inland Sea. In this study, we performed sulfur and diatom analyses of the deposit. The results were used along with 14C dates and the eruption age (7300 cal BP) of Kikai-Akahoya tephra (K-Ab) to derive sedimentary environments of the deposit. K-Ah was detected just below the peat deposit. At the culmination of the Jomon transgression, the peat deposit had been formed in brackish environments of salt marsh for about 300 years. In order to reconstruct local paleovegetation, we analyzed pollen, wood and plant fossils in the deposit. The results show vegetational transition from a deciduous broadleaved forest mainly of Ouercus subgen. Lepidobalanus to Pinus forest. In spite of the Holocene thermal optimum, the vegetation dominated by Ouercus subgen. Cyclobanopsis was not recognized at the Desaki site, as has been shown in many other regions of regions of western Japan. Ouercus sect. Prinus was replaced by Ouercus sect. Aegilops as the dominant section of Ouercus subgen. Lepidobalanus, suggesting early establishment of traditional rural vegetation of 'Satoyama' in Japan. However, no evidence for human agency has been obtained from the mid-Holocene archaeological sites around the Desaki site. Thus it is more likely that this vegetational transition resulted from the succession caused by natural forces such as ecological disturbance and climatic and/or endemic situations rather than by cultural deforestation.
Okayama University Earth Science Report
Department of Earth Sciences Faculty of Science, Okayama University
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