Abstract
Speleothems record successive information on terrestrial paleoenvironment. The vegetation change in Akiyoshi-dai Plateau, Yamaguchi Prefecture, was examined by using d13C values of a stalagmite formed in the grassland area. The stalagmite d13C values largely reflect those of soil CO2 derived from organic carbon associated with d13C values dependent on vegetation. The 7cm tall growing stalagmite sample from Kitayamakita-no-yokoana Cave in grassland was found to record the artificial vegetation change of Akiyoshi-dai Plateau as variations of the d13C values of the carbonate. The average growth rate of a stalagmite (24mm y-1) in Akiyoshi-dai Plateau made it possible to estimate that yearly burning of the dead grass off Akiyoshi-dai Plateau had started about 400 years ago.
