Twigs date the second Holocene transgression in southwestern Norway

Abstract Marine flooding events occasionally interrupted the everyday lives of prehistoric coastal populations. Identification of such events are important for studies of past population dynamics and adaptive strategies. However, short-term events are rarely identified in the geological record, which puts a severe limit on our archaeological interpretive framework. This paper explores the temporality of the second Holocene transgression in southwestern Norway (ca. 3500 BCE) and works under the hypothesis that it was not a slow geological process but rather one or multiple short-term events. A Bayesian approach is used to analyze multidisciplinary time series data collected from sites located in Norway and Shetland. The resulting chronological model supports the hypothesis that the second Holocene transgression in southwestern Norway was a rapid flooding event that occurred in the period 3445–3395 BCE (Early Neolithic II). It is also suggested, but not argued conclusively, that this flooding event could correspond to the Garth tsunami, a paleotsunami named after Garth Loch in Shetland. Considering the potential impact of such a flooding event on the everyday lives of local foragers who dwelled in southwestern Norway, it is anticipated that this study could form a starting point for future case studies.