LATE-QUATERNARY DEPOSITS AT LE MOURA, BIARRITZ, SOUTH-WEST FRANCE

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Summary

The present paper describes pollen-analytical and stratigraphic evidence and macroscopic plant remains from Full-, Late- and Post-glacial deposits at Le Moura, a valley bog near Biarritz, South West France. The last part of the Full-glacial period probably saw the existence of treeless conditions in the area whilst during the Late-glacial period, pine (including Pinus uncinata) and tree birches spread into the area and forested episodes alternated with periods of park woodland and steppe-tundra. In the Late-glacial deposits at Le Moura, indications of hydroseral and terrestial plant successions intermingle in contrapuntal fashion, and only when a detailed palaeo-ecological analysis of the evidence was carried out did any satisfactory indication of climatic change during the period emerge. The main Late-glacial episodes closely parallel those from north-west Europe, a mild forested phase presumably contemporary with the Allerod (zone II) occurs, preceded and succeeded by less wooded, cooler episodes. A pre-Allerød climatic oscillation of apparently short duration and narrow amplitude is tentatively detected. Among the Full- and Late-glacial plant records, Armeria sp., Cryptogramma crispa, Centaurea cyanus, Empetrum nigrum, Ephedra cf. distachya, Erica tetralix, Euphorbia amygdaloides, Pinus sylvestris and P. uncinata, Polygonum cf. viviparum and Valeriana dioica may be noted. The Post-glacial record is incomplete, there being a discontinuity in deposition giving rise to the absence of any records from the whole of the period considered equivalent to British pollen zone VIIb, early zone VIII and late zone VIIa. The dominant woodland species throughout the earlier part of the Post-glacial period are the oaks and pine, with hazel, whilst alder and beech appear towards the top of the diagram. Other mixed oak forest elements are very scarce. Both the strati-graphic and pollen-analytical records show that the end of phase P2 (approximately equivalent to British zone VI) at the site was a relatively dry continental period. Whilst the highest levels of the series include records for recently introduced plants such as maize and a species of cedar, earlier pre-cultural levels include pollen records of Vitis, Olea, Daboecia cantabrica, Erica vagans and Quercus ilex. The biogeographical significance of the plant records and the palaeo-climato-logical reconstructions is briefly discussed.

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