Deglacial to postglacial palaeoenvironments of the Celtic Sea: lacustrine conditions versus a continuous marine sequence

摘要: Recent work on the last glaciation of British Isles has led to an improved understanding nature and timing retreat British−Irish Ice Sheet (BIIS) from its southern maximum (Isles Scilly), northwards into Celtic Irish seas. However, deglacial environments across Sea shelf, extent subaerial exposure existence (or otherwise) a contiguous terrestrial linkage between Britain Ireland following ice remains ambiguous. Multiproxy research, based analysis 12 BGS vibrocores Deep Basin (CDB), seeks address these issues. CDB cores exhibit shell-rich upward fining sequence Holocene marine sand above erosional contact cut in laminated muds with infrequent lonestones. Molluscs, situ Foraminifera diatoms are absent basal muds, but rare damaged freshwater foraminiferal linings occur. Dinoflagellate cysts other non-pollen palynomorphs evidence diverse, environmentally incompatible floras temperate, boreal Arctic glaciomarine taxa co-occurring. Such multiproxy records can be interpreted as representing retreating margin, reworking sediments lacustrine basin. Equally, same record may recording similar conditions within semi-enclosed embayment dominated by meltwater export deposition reworked microfossils. As assemblages contrast markedly proven sequences outside CDB, glaciolacustrine interpretation is favoured for sequence, truncated Late Weichselian transgressive upwards fully conditions. Reworked intertidal molluscs immediately regional unconformity provide minimum date c. 13.9 cal. ka BP commencement widespread erosion. Although suggestive conditions, exact sediment implications this (pen)insularity deglaciation, remain elusive.