1985 Volume 37 Issue 3 Pages 159-165
Radiocarbon dating and pollen analysis have been done on two peat beds lying above and below the Sukawa volcanic debris avalanche deposit. A nearly 100m thick avalanche of the Sukawa volcanic debris which occured on the south side of Mt. Ryu-zan representing the western section of the Zao volcanoes spread over an area of about 1 to 7km wide and 12km long. Our study indicates that the Sukawa avalanche deposit gives an age not much older than 40, 000 years B. P. and is assignable to a horizon between the subinterglacial to subglacial stages on the basis of palynological evidence. These data enable a tentative correlation of the avalanche episode with the early-glacial to plani-glacial substage in the Würm Ice Age.