Characteristics in trace elements compositions of tephras (B-Tm and To-a) for identification tools

• DOI: 10.2343/geochemj.2.0619
• Publication Date: 2021-11-21T22:08:37Z
• Authors: Fumiko Watanabe Nara; Tatsunori Yokoyama; Shin-ichi Yamasaki; Masayo Minami; Yoshihiro Asahara; Takahiro Watanabe; Kazuyoshi Yamada; Noriyoshi Tsuchiya; Yoshinori Yasuda
• Keywords: Trace element; Volcanic glass

The absolute date of the Millennium Eruption (ME) Changbaishan Volcano is widely recognized as AD 946. Baegdusan-Tomakomai (B-Tm) tephra dispersed during ME a robust-age key bed. In order to identify tephra, refractive index and major-element compositions volcanic glass shards are conventionally used. Meanwhile, trace-element analysis using inductively coupled plasma mass spectrometry (ICP-MS) technique for bulk samples B-Tm still limited. Here we give detailed description major- sediments Towada caldera eruptions (To-a) deposits from Lake Ogawara sediment core, Tohoku region, northern Japan tephras. depth profiles major trace elements show significant peaks K2O some (Zn, Rb, Zr, Nb, Sn, Y, La, Ce, Nd, Th, U) at layer in but no these To-a layer. High concentrations were observed individual well sediment. These highlighted by elemental abundance pattern normalized crustal abundance. other Japanese tephras showed differences those especially REE compositions. strong tool distinguishing