Black Sea - Palaeoclimate and geomagnetic archive: GFZ

Black Sea - Palaeoclimate and geomagnetic archive

Map of the Black Sea showing the working areas and retrieved sediment cores during various Black Sea expeditions of the last five years (left). General stratigraphic classification of the glacial/postglacial sediment sequence in the Black Sea. C1 and... — Map of the Black Sea showing the working areas and retrieved sediment cores during various Black Sea expeditions of the last five years (left). General stratigraphic classification of the glacial/postglacial sediment sequence in the Black Sea. C1 and C2 indicating periods of late/postglacial inorganic carbonate precipitates that are interrupted by the Younger Dryas cold period (YD) (Bahr et al. 2005, 2006, 2008; Kwiecien et al. 2008). RL stands for “Red Layers” and describes the systematic occurrence of reddish clays in the western Black Sea basin. *(GFZ)*

Grayscale measurements on the laminated marine Units I and II sediments recovered from the southwestern Black Sea displaying the major changes during the last 8300 years of the most recent marine stage of the Black Sea.

As an isolated marginal sea, the Black Sea reacted particularly sensitive to paleoenvironmental changes and amplifies both global and regional climate signals. In spite of its unique potential for high-resolution paleoclimate reconstructions, the Late Quaternary sedimentary sequence of the Black Sea has only subordinately been studied with respect to paleoclimatic questions. As the most distant arm of the Atlantic Ocean, the Black Sea demonstrates an unparalleled feature: it oscillates between lacustrine and marine stages following, respectively, glacial-interglacial sea level changes. Moreover, the geographic location of the Black Sea and the presence of laminated sequences during global sea-level highstands are ideal to study variability and interactions of Mediterranean, temperate central to eastern European, and continental paleoclimates of western Asia on different time-scales ranging from millennia to interannual.

In the course of the last five years, we recovered several sediment cores from the continental slop areas of the Black Sea. During the RV METEOR cruise M51-4 in 2002, we focussed on the northwestern and southwestern Black Sea. During the IMAGES cruise ASSEMBLAGE II in May 2004, we revisited the southwestern area and recovered an extra long sediment core through the GALYPSO coring system, penetrating deep into the glacial lacustrine sediments of the Black Sea. Finally, during RV METEOR cruise M78-5in 2007, we investigated two areas neighbouring the Crimean Peninsula and the region east of the Sinop Peninsula in the southeastern Black Sea.

Analyses of the ~8-m-long sediment core GeoB 7622 from the southwestern Black Sea reveal an exceptional potential for ultra high resolution paleoenvironmental studies. At least during the anoxic interval of the last ca. 8300 years, regional sedimentation rates are about ten times higher than on the abyssal plains due to enhanced terrigenous sediment input. The generally varved sequence is characterized by frequent intercalations of homogeneous clay layers that are interpreted as suspension fallout events from the Sakarya river plume related to increased winter-rain in western Anatolia (Lamy et al. 2006).

Partner: André Bahr (DFG Forschungszentrum Ozeanränder, Bremen, now IFM Geomar, Kiel), Fank Lamy (AWI Bremerhaven), Bo Barker Jorgensen (MPI Bremen)

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