HOLIVAR2006 Abstracts
Reconstruction of the last 140,000 yr fire history from microscopic charcoal in Lake Biwa sediments, central Japan. Abundant charcoal in Early Holocene sediments is derived from anthropogenic fires or natural fires related to climatic change?
Jun Inoue1, Hikaru Takahara2, Shusaku Yoshikawa1 and Yoshio Inouchi3
1Graduate School of Science, Osaka City University,3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
2Graduate School of Agriculture, Kyoto Prefectural University,1-5 Hangi-cho, Shimogamo, Sakyo-ku, Kyoto 606-8522, Japan
3Faculty of Science, Ehime University, Bunkyo-cho 2-5, Matsuyama, Ehime 790-8577, Japan
Contact: Jun Inoue (juni@sci.osaka-cu.ac.jp)
The fire history suggested from microscopic charcoal in sediments is often related to climatic change and vegetation change or ancient human activities. We examined the microscopic charcoal concentrations and influxes of Lake Biwa sediments corresponding to last 140,000 yr (Marine Isotope Stage 1 to 5) by use of the pollen slide method to reconstruct fire history. Very little charcoal is preserved in the sediments corresponding to late Pleistocene (140,000 to 13,000 cal. yr BP). The highest or higher charcoal concentrations and influxes are recognised in sediments of Early Holocene. This evidence indicates that the fire frequency of the Early Holocene is higher than in any other periods. The palynological research of the Lake Biwa sediments suggested the period of the last c. 10 kyr matched interglacial period (MIS1) and had wet and cool to warm climatic conditions (Miyoshi et al. 1999).
Did warmer climatic condition in the Early Holocene increase the fire frequency around Lake Biwa? If so, why is little charcoal preserved in sediments of another interglacial period (MIS5)? Alternatively, ancient human activity might increase fire frequency. In Japan, the Jomon Era started around the Early Holocene, which was characterised by a hunting-and-gathering lifestyle and the start of using earthenware. It is considered that in the Jomon Era, people began to settle down around Lake Biwa. Is the ancient people's burning in the Early Holocene indicated by microscopic charcoal in the sediments?
Jun Inoue is a research student in the Department of Geoscience, Faculty of Science, Osaka City University. The aim of his study is reconstruting the fire history in Japan by use of charcoal fragments in sediments.