Abstract
Planktonic foraminifera in cores HS02 (northwestern Izumo Plain) and GH87-2-308 (off Tottori) were used to document the occurrence of warm-water fauna and infer the presence of the Tsushima Warm Current in the coastal region of the southern Sea of Japan during the Early-Middle Holocene. Based on the downcore distribution of Globigerinoides ruber, a warm-water planktonic foraminifer, in core GH87-2-308, the influence of the Tsushima Warm Current was significant at ca. 8.3—8.0 and ca. 7.3—6.8ka. This species is also found at the ∼7.8ka level in core HS02, showing the presence of a warm-water benthic fauna in “Paleo-Shinji Bay.” According to previous floral and faunal studies in the hemi-pelagic region (e.g. Oki Ridge) of the Sea of Japan, warm-water taxa were common around ca. 7.3ka, but were not common during the 8.3—7.8ka interval. It is suggested that the influence of the Tsushima Warm Current was significant along the San-in District coast at ca. 8.3—7.8ka, and it contributed to the occurrence of warm-water faunas in this area, including “Paleo-Shinji Bay.”
