Raised beach sands at Hedderwick
Tsunami deposits near Dunbar
David Smith and others have described the southernmost example of likely deposits of the Storegga tsunami at ~7300 BP from amongst the raised beach deposits at Hedderwick. The deposits are almost uniformly horizontally-bedded and well sorted sands grading into muds further into the estuary. One or two prominent gravel layers occur, however, with rip-up clasts of mud and broken shells. In the sheltered wave environment of the Tyne estuary these coarse deposits must relate to either major storms or tsunami. As sea level 7300 years ago was 5-8 m above the present the deposits are unlikely to be products of storm waves. Aside from the tsunami deposit, the excellent exposures in the raised beaches around Hedderwick await further study.