Examination of cryptotephrostratigraphy performed by recycling the residue from samples used in a paleoceanographic study of foraminiferal fossils from the MD01-2421 sediment core collected off the Kashima coast of East Japan

Abstract

Residues from foraminiferal research samples from the MD01-2421 core collected off the Kashima coast, East Japan were used for cryptotephra detection. The esidues were carefully divided to maintain the foraminiferal community composition in the samples. As a result, data from 419 volcanic glass shards in the deposits from the top of the core to a depth of 9.5 cm were obtained, and cluster analysis was performed after normalizing the datasets. In one of the clusters with sample properties ranging from rhyolite to dacite, volcanic glass shards could be correlated to the As-A tephra that erupted from Mt. Asama, Central Japan in 1783 AD