Abstract
The Ta-d tephra (8.7–9.2 cal. ka) from Tarumai Volcano in south-western Hokkaido has been newly recognized at two archeological sites and in cores taken from a bay in the Kushiro–Nemuro area, eastern Hokkaido, Japan. Identification of the tephra is based on chronological data, stratigraphic relationships (it is overlain by the 2.5 cal. kyr old Ta-c2 tephra), lithofacies, and petrological correlation (modal mineralogy and glass chemistry) with proximal Ta-d tephra deposits. In particular, the relatively high TiO2 and low K2O contents of the tephra are distinctive. The Ta-d tephra comprises lower pumiceous and upper scoriaceous parts, and is well preserved in the distal Kushiro region as a 5-cm-thick tephra layer. The Ta-d tephra may be a useful chronostratigraphic marker for the early Holocene in eastern Hokkaido and bordering regions of the Pacific Ocean.
