Conference:
EEDEN, State of the art, 16-18 November 2000, Lyon, France, p. 52.
Authors:
Jean-Pierre Suc, Simona Boroi, Speranta-Maria Popescu, Gonzalo Jiménez-Moreno, Stephan Klotz.
Abstract:
An intensive effort in high-resolution pollen analysis was performed on five cores, four in the Black Sea (one on the shelf: BLKS98-10; one on the slope: B2KS38; two in the deep basin: B2KS33 and DSDP Site 380A), one in the Marmara Sea (C10), in order to reconstruct vegetation and climate of the Last Climatic Cycle. Core B2KS38 belongs to an area directly influenced by terrigenous inputs from Danube River and shows a dilated sedimentation during the Younger Dryas. The present-day pollen record from surface samples (Fig. 1) evidences some respective influence of (1) mesothermic (i.e. warm-temperate) forests from the western side of the Black Sea and the northern Turkish shoreline and (2) open vegetation (including Artemisia steppes) from the Anatolian Plateau (to the South) and Crimean Peninsula (to the North) (Zohary, 1973; Quézel and Médail, 2003). In such a sensitive vegetation area (Hammen et al., 1971), this coeval contrasted pattern prefigures the opposing pollen floras which successively predominated during the recent past climatic fluctuations. First, it is to be noticed the continuous important role of the area as a refuge province for thermophilous plants (for example, Taxodiaceae, from which percent- ages regularly decrease since the Last Interglacial, disappeared only very recently, probably because of human action). These five cores provide an almost continuous record from about 180 ka up to Present. Forests extended during warm phases and Artemisia steppes during the cold ones. The Late Glacial and Holocene are particularly well documented in cores BLKS98-10, B2KS38 (which shows a outstandingly dilated Younger Dryas), and B2KS33 and C10 (which displays a very detailed Holocene). Such high-resolution pollen records make possible narrow relationships with the GRIP oxygen isotope curve (Dansgaard et al., 1993). Palaeoclimatic parameters have been calculated thanks to a transfer function (Klotz et al., 2004): the mean annual temperature from the Late Glacial to Holocene fluctuated between 5 and 12°C, while annual precipitation fluctuated between 500 and 850 mm. It can be expected that this composite pollen record will shortly constitute a reference detailed pollen series for the Last Climatic Cycle and will match with the previous reference pollen series for the northeastern Mediterranean region (Tenaghi Philippon, northeastern Greece) (Hammen et al., 1971).