Early Devensian interstadial and glacigenic sediments in Gwynedd, North Wales

• Published in: Geological Journal
• Main Authors: Addison, K., Edge, M. J.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1992
• Subjects: Sea ice
• Online Access: http://dx.doi.org/10.1002/gj.3350270208; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1002%2Fgj.3350270208; https://onlinelibrary.wiley.com/doi/pdf/10.1002/gj.3350270208

Abstract Recent excavations at Pen‐y‐bryn, Caernarfon have revealed a series of organic deposits below and within a glacial till of Welsh ice provenance. This paper presents the results of 14 C analyses carried out on tree wood and organic peaty muds, together with a description of the site stratigraphy. Pen‐y‐bryn is the first Welsh site from which in situ biogenic deposits directly enclosed by glacigenic sediments and yielding finite radiocarbon dates have been recovered. Radiocarbon, plant macrofossil, palynological, fossil coleopteran and lithostratigraphic evidence suggest that this is the first site in Wales at which at least one Early Devensian interstadial episode followed by an Early Devensian stadial ice advance may be represented. Snowdonian glacier ice appears to have buried some of the organic deposits beneath till and incorporated other organic material within the till before a later advance of Irish Sea ice. This evidence is used to construct a Devensian chronostratigraphy which may involve two glacial stadia rather than a single Late Devensian glaciation.