Conference:
Séance spécialisée AFEQ –SGF, Paris, 3 décembre 2009, France.
Authors:
Jean-Pierre Suc, Speranta-Maria Popescu, Demet Bilteken, Nathalie Combourieu-Nebout, Hanna Winter, Stephan Klotz.
Abstract:
The Lower Pleistocene vegetation in Europe, Mediterranean region and Middle East is more or less continuously documented by some 31 pollen localities. They allow to reconstruct (1) the spatial organization of vegetation during interglacials and glacials (Suc & Popescu, 2005), and (2) the timing and determinism of thermophilous plant extinction (Suc et al., 2004; Svenning, 2003). A long pollen record from the Black Sea (DSDP Site 380) covers at high chronologic resolution the interval 2.6 – 0.8 Ma (Popescu et al., submitted). Particularly, it provides a complete archive of the earliest glacial-interglacial cycles which were characterized, at their beginning, by fast alternations (41 kyrs) between arboreal phases (dominated by the coastal Taxodiaceae Glyptostrobus) and the Anatolian Artemisia steppe. At ca. 1.3 Ma, 100 kyrs climatic cycles replaced the previous ones and corresponded to alternating warm-temperate forests (including some relictuous Glyptostrobus) and Artemisia steppes. The southern Italy is a very propitious region because mountains are next to the shoreline and marine pollen records show changes occurred in the different altitudinal vegetation belts which reflect the coeval changes at the latitudinal scale of Europe. The Crotone series is very important as its longitude allows to clarify the respective influence of precession and obliquity (Joannin et al., 2007; Suc et al., accepted). Taxodiaceae (Sequoia) and Cathaya forests inhabited the mountainous slopes during interglacials where Artemisia steppe developed during glacials (Combourieu-Nebout, 1993; Suc et al., accepted). The most thermophilous trees (Taxodiaceae mainly) progressively reduced up to disappear from the region (Montalbano Jonico section: Joannin et al., 2008). However, glacial-interglacial cycles were characterized by clear succession in plant ecosystems.