Interpretation of the pollen stratigraphy of Late Devensian lateglacial and early Flandrian sediments at Llyn Gwernan, near Cader Idris, North Wales

Abstract

Pollen‐stratigraphic information is presented for two profiles from a high resolution Devensian lateglacial succession at Llyn Gwernan, North Wales. Pollen concentration and preservation data are available for one of these profiles and two series of radiocarbon dates, one based on‘conventional’radiometric counting and one on accelerator mass spectrometry measures, provide age estimates for the succession. The data indicate the following sequence of events at Llyn Gwernan: deglaciation of the area about or shortly before 14200 n. p.; cold, dry climatic conditions from 14200 to 13 200 n. p.; generally stable environmental conditions from 13 200 to 12 100 B.P.; steady deterioration of climate between 12100 and 11 160 B.I.; harsh climatic conditions between 11 160 and 10200–10000 B.P. This interpretation broadly supports that previously proposed for N. Wales on the basis of coleopteran evidence. Implications of some of the differences in pollen stratigraphy between the two Llyn Gwernan profiles and possible evidence for two minor climatic oscillations during the lateglacial interstadial are discussed. Copyright © 1989, Wiley Blackwell. All rights reserved