Dates from drowned mid-Holocene landscapes on the central western Irish seaboard

Abstract

The Holocene in Ireland was a time of rapidly rising sea level that continued up to about 5000 years ago. This transgression lead to the flooding of mid-Holocene forested landscapes along the western seaboard of the country. Carbon 14 dating of in situ tree stumps set in peat from these forests shows a span of dates from approximately 7400 to 5200 years cal. BP from counties Mayo, Galway and Clare. Peat deposits of up to 2m thickness formed during this time. These dates firstly show that these forests were long-lived features of the Irish landscape. Secondly their presence suggests that at this time sea level was probably lower than that suggested in glacial rebound models for the area. Thirdly the general absence in these peats of evidence of marine incursion confirms that the Holocene highstand did not occur along the central part of the western Irish seaboard, unlike in areas along the north and east coasts of the country.