A Review of Late Quaternary Deep-sea Tephras Around Japan

A new local marine reservoir correction for the last deglacial period in the Sanriku region, northwestern North Pacific, based on radiocarbon dates from the Towada-Hachinohe (To-H) tephra

“…The To-H tephra originates from the Towada caldera in the northern Tohoku district, northern Japan. In terrestrial sequences, the reported radiocarbon ages of To-H are in the range 12.2-14 14 C ky BP (Machida and Arai, 2003). Hemipelagic sedimentation rates of core KR05-04 PC15, excluding turbidites from the total sediment thickness, based on radiocarbon ages obtained for planktonic foraminifera (Table 3) were calculated to be 12.7-41.1 cm/ky, but have varied since the last glacial maximum (LGM) (Fig.…”

“…Discussions 1. The local reservoir effect during the last deglaciation near Sanriku Previously reported radiocarbon ages for the terrestrial To-H tephra range from 12.2 14 C ky BP to 14 14 C ky BP (Machida and Arai, 2003). Terada et al (1994) obtained radiocarbon dates from buried tree trunks (12,660±150 14 C y BP and 12,640±150 14 C y BP) by the Towada-Hachinohe pyroclastic flow deposits.…”

“…1). Machida and Arai (2003) reported the occurrence of the Baegdusan-Tomakomai (B-Tm ; 10 th Century), Towada-a (To-a ; AD915), To-H, and To-Of tephras in core P82 (40°53.7′N, 142°16.7′ E ; water depth : 1,150 m) off Rokkasho. Ohkushi et al (2007) found To-H in two cores collected off Rokkasho (core MR01-K03 PC4 ; 41°07′N, 142°T able 1 Locations and water depths of the cores recovered from the Sanriku region during research cruises KR05-04 and KR07-05 24′E ; water depth : 1,363 m ; and core KT90-9 St.5 ; 41°06′N, 143°30′E ; water depth : 2,048 m).…”

“…Aoki and Arai (2000) recorded the tephrostratigraphy of core KH94-3 LM-8 from east of Kesennuma, Sanriku (38°53.52′N, 143°22.11′E ; water depth : 2,353 m), above the Aso-4 tephra, erupted from the Aso caldera, central Kyushu, southern Japan. They recognized 14 tephra beds, and were able to correlate some with widespread tephras such as Aso-4 (85-90 ka), Spfa-1 (40-45 ka), TowadaOfudo (To-Of ; older than 32 ka during MIS 3), AT (26-29 ka), To-H (around 15 ka), and TowadaChuseri (To-Cu ; 6 ka), in ascending order (eruption ages from Machida and Arai, 2003). Minoshima et al (2007a) also found the To-H tephra in core KR02-15-PC6 (40°23.89′N, 143°2…”

“…found the To-H, To-Of, and, Spfa-1 tephras above Aso-4 in core MR99-K04 PC-1 (40°33.3′N, 142°55.0′E ; water depth : 1,555 m) near Hachinohe, and the To-H, To-Of, KuccharoShoro (Kc-Sr ; 35-40 ka ; Machida and Arai, 2003), Spfa-1, and probable Naruko-Yanagisawa (Nr-Y) tephras (41-63 ka ; Machida and Arai, 2003) above Aso-4 in core MR99-K04 PC-2 (40°0 5.0′N, 149°51.0′E ; water depth : 5,608 m) from the NW Pacific ocean floor (not shown in Fig. 1).…”