Termination of the last glaciation in the Iberian peninsula inferred from the pollen sequence of Quintanar de la Sierra
Résumé
A 4.5-m-thick late-glacial pollen sequence, supported by 17 AMS C-14 dates, has been investigated at the Quintanar de Ia Sierra marshland (Iberian cordillera, north-central Spain), Pollen zones were defined that correspond to successive phases in vegetation history during the end of the Late Wurm, late-glacial interstade, and Younger Dryas periods, A transfer function approach has been adopted to derive quantitative climate estimates from the pollen assemblage data. A first expansion of Juniperus and Hippophae, about 13,500 C-14 yr B.P., indicates the beginning of the late-glacial interstade which is characterized by a Juniperus-Betula-Pinus succession that suggests higher temperatures and moisture than during full-glacial time, The Younger Dryas interval is recorded by a 120-cm-thick sediment unit that is dominated by herbaceous pollen, Transfer function estimates suggest that the climate during this period was cold, with low precipitation during most of the year, although not in summer, The Holocene arboreal recolonization in the area started about 10,000 C-14 yr B.P., with a renewed Juniperus-Betula-Pinus succession related to a strong increase in annual temperature and precipitation. The start of this process was synchronous with mean sea-surface temperature changes, as recorded from the nearby SU 81-18 marine core. The strong affinity with other European late-glacial pollen sequences demonstrates that the pattern of climatic changes during the last glacial-interglacial transition was similar in both northwestern and southwestern Europe. (C) 1997 University of Washington.