Sakurajima-Satsuma (Sz-S) and Noike-Yumugi (N-Ym) tephras: New tephrochronological marker beds for the last deglaciation, southern Kyushu, Japan

Type Article
Date 2011-12
Language English
Author(s) Moriwaki Hiroshi1, Suzuki Takehiko2, Murata Masanori2, Ikehara Minoru3, Machida Hiroshi, Lowe David J.4
Affiliation(s) 1 : Kagoshima Univ, Fac Law Econ & Humanities, Kagoshima 8900065, Japan.
2 : Tokyo Metropolitan Univ, Dept Geog, Tokyo 158, Japan.
3 : Kochi Univ, Ctr Adv Marine Core Res, Kochi 780, Japan.
4 : Univ Waikato, Dept Earth & Ocean Sci, Hamilton 3240, New Zealand.
Source Quaternary International (1040-6182) (Pergamon-elsevier Science Ltd), 2011-12 , Vol. 246 , N. 1-2 , P. 203-212
DOI 10.1016/j.quaint.2011.03.046
WOS© Times Cited 16
Note In : Enhancing tephrochronology and its application (INTREPID Project): Hiroshi Machida commemorative volume
Abstract Two prominent tephras, Sakurajima-Satsuma (Sz-S) erupted from Sakurajima volcano and Noike-Yumugi (N-Ym) erupted from Kuchierabujima Island, provide new key marker beds for dating and synchronizing palaeoenvironmental and archaeological records in the last deglaciation in southern Japan. These tephras were identified on the basis of glass major-element compositions in two distal areas, a marine core (IMAGES MD982195) in the northern part of the East China Sea and on the central part of Tanegashima Island, and we related their stratigraphic positions to the marine oxygen isotope-based chronology. In MD982195, Sz-S, 0.8 cm in thickness at 9.12 m depth and N-Ym, 3 cm in thickness at 9.30 m depth, are both white, vitric, ash-grade tephras. On Tanegashima Island, Sz-S, 10 cm in thickness and N-Ym, 3 cm in thickness, are stratigraphically constrained by well-characterised marker tephras Kikai-Akahoya (7300 cal BP) and Aira-Tn (29,000 cal BP). Sz-S is rhyolitic and homogeneous on the basis of glass major-element compositions assayed by electron microprobe. Pumiceous glass shards predominant in distal Sz-S tephra indicate that it derived from pumice fall units that correspond to pumiceous and phreatomagmatic fine ash units constituting proximal Sz-S tephra. N-Ym is rhyolitic and glass major-element analyses reveal compositional diversity between units, suggesting that the lower and middle tephra units dispersed to the east, whereas the upper unit was dispersed north to northwest from the vent. Stratigraphically, Sz-S occurs at around the start of the late-glacial reversal (cooling) in oxygen isotope records of MD982195, corresponding to the end of GI-1 and the start of GS-1 in the ice-core events of NGRIP (GICC05), consistent with a terrestrial age of similar to 12,800 cal BP. Based on the oxygen isotope stratigraphy, the tephra identified in the core as N-Ym at 9.30 m depth is close to the end of Greenland GI-1 and hence has an age of similar to 13,000 cal BP, but on Kuchierabujima Island it has an age based on C-14 assay of charcoal of c. 14,900 cal BR Although this age discrepancy (14.9 vs 13.0 cal ka) needs resolution, the occurrence in core MD982195 of N-Ym shows that it is more widespread than hitherto demonstrated. The widespread distributions and key stratigraphic positions for the two marker tephras indicate that they are thus critical isochrons for precise correlation of palaeoenvironmental changes and prehistoric cultural events during the last deglaciation in southern Kyushu, and for relating such changes and events to the ice-core chronology via the marine oxygen isotope chronostratigraphy.
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Moriwaki Hiroshi, Suzuki Takehiko, Murata Masanori, Ikehara Minoru, Machida Hiroshi, Lowe David J. (2011). Sakurajima-Satsuma (Sz-S) and Noike-Yumugi (N-Ym) tephras: New tephrochronological marker beds for the last deglaciation, southern Kyushu, Japan. Quaternary International, 246(1-2), 203-212. Publisher's official version : https://doi.org/10.1016/j.quaint.2011.03.046 , Open Access version : https://archimer.ifremer.fr/doc/00226/33774/