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Younger Dryas to mid-Holocene environmental history of the lowlands of NW Transylvania, Romania |
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| Authors: | Angelica Feurdean Volker Mosbrugger Bogdan P Onac Victor Polyak Daniel Veres |
| Institution: | a School of Geography, Centre for the Environment, University of Oxford, South Parks Road, OX1 3QY, Oxford, England b Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, 60325, Frankfurt, Germany c Department of Geology, University of South Florida, 4202 E. Fowler Ave., SCA 528, Tampa, FL 33620, USA d Quaternary Research Group, “Babes-Bolyai” University Cluj and “Emil Racovita” Institute of Speleology, Clinicilor 5, 400006, Cluj, Romania e Earth and Planetary Sciences, University of New Mexico, 200 Yale Blvd., Northrop Hall, Albuquerque, NM 87131, USA f Department of Physical Geography and Quaternary Geology, Stockholm University, SE-10691 Stockholm, Sweden |
| Abstract: | Pollen, micro-charcoal and total carbon analyses on sediments from the Turbuta palaeolake, in the Transylvanian Basin of NW Romania, reveal 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. 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 8000 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 8000 cal yr BP it replaced Quercus as a dominant forest constituent, with only little representation of Picea abies. Carpinus became established around 5500 cal yr BP, but it was only a minor constituent in local woodlands until ca. 5000 cal yr BP. Results from this study also indicate that the woodlands in the lowlands of Turbuta were never closed. |
| Keywords: | Transylvania Pollen Total carbon AMS 14C U/Th TIMS Vegetation changes Lowlands Younger Dryas Holocene |
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