Article:
AAPG European Regional Conference, Tbilisi, Georgia, 26-27 September 2013.
Authors:
Speranta-Maria Popescu, Jean-Pierre Suc, Mihaela-Carmen Melinte Dobrinescu.
Abstract:
Late Neogene and Quaternary sediments of the Black Sea are difficult to manage in terms of chronostratigraphy because they are usually very poor or barren in marine biostratigraphic markers (foraminifers, calcareous nannoplankton). However, they are very rich in pollen grains, which allow temporal high-resolution quantitative analyses and evidence of resulting cyclic environmental changes referred to global climate evolution. DSDP Site 380 (southwestern Black Sea) has been analysed for its palynological content. Occurrence in several samples of dinoflagellate cysts first indicated repeated incursions of marine waters. Calcareous nannofossils have been searched in these samples, and provided a rough biostratigraphic frame from about 5.3 Ma to 1 Ma, in addition to the ‘Pebbly Breccia’ marking the Messinian Salinity Crisis (Gillet et al., 2007). Consequently, repeated cyclic alternations on the pollen content between prevalent thermophilous trees and herbs (including steppe elements) were interpretable as resulting from climatic fluctuations and robust cyclostratigraphic relationships have been established with standard reference oxygen isotopic curve. These results represent a high stratigraphic improvement on this material, allowing accurate correlations with other pollen records both at the regional and global scales (Popescu, 2006; Popescu et al., 2010). These studies confirm the extensive strength of pollen analysis as a tool for correlations over large distance.