Pollen analysis of Holocene sediments from Loch Etive, a Scottish fjord

Abstract

AbstractThis paper outlines one of the first attempts to analyse the detailed pollen content of the marine sediments from a fjord (sea loch) located on the west coast of Scotland. The site chosen was in the Bonawe Deep, part of the upper basin of Loch Etive, and 2.3 m depth of sediments were sampled. These sediments were examined for their fossil pollen content and a pollen diagram was constructed from the results. The interpretation of the pollen record was supported by seven radiocarbon dates which demonstrated that the sediments accumulated over the last 8–9 ka of the Holocene. The pollen diagram was divided into three pollen assemblage zones. The lowest zone ET1 (c. 9–7.3 ka BP) was dominated by pollen of Betula, Pinus and Corylus, zone ET2 (c. 7.3–1.2 ka BP) contained a wide range of woodland pollen taxa (mainly Betula, Pinus, Quercus, Alnus and Corylus) and the uppermost zone ET3 (1.2–0 ka BP) was distinguished by fewer tree pollen taxa and increased values of open habitat taxa, particularly Calluna. The pollen diagram showed the development of vegetation during the Holocene which correlated well with existing results from studies of peat or freshwater lake sediments sampled in the west of Scotland. The only significant differences were the higher concentrations of Pinus pollen found in the Loch Etive site. These differences can be explained by the large catchment area of the loch which includes high ground, where it is proposed that extensive Pinus forest grew during much of the Holocene. The study demonstrates the practicality of using Scottish fjord sediments for Holocene pollen studies and potentially provides a link between terrestrial vegetation records and marine-based fossil records.