遠隔地における完新世の三瓶山起源の降下堆積物

Volcanic ash layers originating from Mt．Sanbe has been identified at new outcrops（Locations D，E and F，east of Mt．Sanbe），based on（1）biotite content analysis（number of biotite particles by numbers of biotite＋amphibole-group particles multiplied by 100），（2）analysis of volcanic glasses（size，refractive index and other parameters）and（3）^<14>C age measurements of black soil layers above and below the ash beds．These analyses show that two ash layers at Locs．D and E are correlative with the Taiheizan and Tsunoi Ash layers，respectively．A single ash bed with high biotite content at Loc．F seems to be the Taiheizan ash layer．