The experimental analysis on the Late Quaternary deposits of the Black Sea

Holocene sediments taken from the south-eastern and western Black Sea have been investigated in relation to their geochemical, sedimentological and mi neralogical characteristics. Their textures are characterized by their low amount of sand, upward-increasing silt and downward-increasing clay content s. While the terrigenous materials transported from Anatolian volcanic-base d sources and European alluvial sediments form the shore deposits, the deep -sea sediments mainly consist of the marine biological production. The high est amount of organic carbon was deposited following the formation of anoxi c conditions at the bottom until the beginning of the still continuing carb onate-rich coccolith (Emiliania huxleyi) deposition. The high metal concent rations are associated with fine-grained sediments, some with organic mater ial. The metal concentration is diluted by high organic carbon and carbonat e contents within the depositional sequences. While the abundance of illite in the western Black Sea describes the deltaic depositions, the downward d ecreasing smectite/illite ratio along the core, off the south-eastern shelf , indicates the downward increasing precipitation during the deposition. Th e variation in the sedimentation pattern and sedimented material is believe d to be the response of the biochemical environment in the sea to the chang ing geological, biological and chemical conditions in and around the Black Sea during the last climatic changes. (C) 2001 Ifremer/CNRS/IRD/Editions sc ientifiques et medicales Elsevier SAS.