Holocene geomorphological environmental changes around the mouth of the Lake Ogawara-ko, Aomori Prefecture, Northeastern Japan

Abstract

Lake Ogawara-ko is a brackish lake located in the eastern part of Aomori Prefecture, Japan. There are a lot of Jomon archaeological sites including shell middens on the Pleistocene terraces and sand dunes around the lake. We have been conducted field surveys to clarify Holocene geomorphological environmental changes surrounding the Jomon archaeological sites. In this study, we discussed on Holocene geomorphological environmental changes around the lake mouth based on newly obtained core materials. As the results, it was suggested that a flood tidal delta formed during the transgressive period, and tidal flats expanded after ca. 6 to 6.5 ka.