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

Abstract

Tephra is a geologically synchronous key bed that can be used to connect depositional environments ranging from terrestrial, through coastal, shallow, and deep marine, to trench. Therefore, tephra represents a uniquely important link between the geological records of terrestrial and marine settings. An understanding of the local marine reservoir effect (ΔR) is important when calibrating radiocarbon dates obtained from marine materials with calendar dates, and when correlating geological and paleoenviron- mental events across different locations. Comparison of radiocarbon dates obtained from a tephra layer deposited on marine (planktonic foraminifera) and terrestrial (buried tree trunks) materials indicates that a local marine reservoir correction of around 830 y must be applied to dates obtained for the last deglacial period from the offshore area near Sanriku, in the western NW Pacific.