HR: 0800h
AN: GC31A-0108    [Abstracts]
TI: Younger Dryas To Mid-Holocene Environmental History Of The Lowlands Of NW Transylvania, Romania
AU: Feurdean, A
EM: angelica.feurdean@ouce.ox.ac.uk
AF: School of Geography, Center for the Environment, University of Oxford, South Parks Road, Oxford, OX1 3QY, United Kingdom
AU: Mosbrugger, V
AF: Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, Frankfurt, 60325, Germany
AU: * Onac, B P
EM: bonac@cas.usf.edu
AF: Department of Geology, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, FL 33620, United States
AU: Polyak, V
EM: polyak@unm.edu
AF: Deaprtment of Earth and Planetary Sciences, University of New Mexico, 200 Yale Blvd., Northrop Hall, Albuquerque, NM 87131, United States
AU: Veres, D
EM: daniel.veres@natgeo.su.se
AF: "Emil Racovita" Institute of Speleology, Clinicilor 5, Cluj, 400006, Romania
AB: Pollen, micro-charcoal and total carbon analyses on sediments from the Turbuta profile located in the Transylvanian Basin (NW Romania) reveal information on previously unknown Younger Dryas to mid-Holocene environmental changes. The chronostratigraphy relies on AMS ¹⁴C measurements on organic matter and U/Th TIMS datings of snail shells. Results indicate the presence of Pinus and Betula open woodlands with small populations of Picea, Ulmus, Alnus and Salix before 12,000 cal yr BP, correlates well with the environmental developments expected for Younger Dryas stadial. A fairly abrupt replacement of Pinus and Betula by Ulmus dominated woodlands at ca. 11,900 cal. yr BP, likely represents competition effects of vegetation driven by climate warming at the onset of the Holocene. By 11,000 cal yr BP, the woodlands were increasingly diverse and dense with the expansion of Quercus, Fraxinus and Tilia, the establishment of Corylus, and the decline of upland herbaceous and shrubs taxa. The marked expansion of Quercus accompanied by Tilia between 10,500 and 8,000 cal yr BP could be the result of low effective moisture associated with both low elevation of the site and with regional change towards a drier climate. At 10,000 cal. yr BP Corylus spread across the region, and by 8,000 cal yr BP it replaced Quercus as a dominant forest constituent, with only little representation of Picea abies. Carpinus became established around 5,500 cal yr BP, but it was only a minor constituent in local woodlands until ca. 5,000 cal yr BP. Results from this study also indicate that the woodlands in the lowlands of Turbuta were never closed.
DE: 0458 Limnology (1845, 4239, 4942)
DE: 1105 Quaternary geochronology
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1637 Regional climate change
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting