Литостратиграфия и литофациальные особнности верхнечетвертичных глубоководных осадков Западночерноморской депресии

Kh. Khrischev, E. Vassilev, V. Georgiev, E. Kozhoukharov, N. Ruskova, S. Chochov, V. Shopov, D. Yankova. Lithostratigraphy and lithofacies features of Upper Quaternary deep sea sediments in the West Black Sea Depression. Two type of variability of macroscopic characteristic, were established in lithostratigraphic units Ia, Ib and Ic – vertical and horizontal. The first is expressed in the presence of packets of regional occurrence and stratigraphic sense. The horizontal compositional variability within the units reveal lithophacies which fix deviations from the type development.
   The Neoeuxinian unit Ic is characterized by terrigeneous sediments with predominance of lutites. The following packet were divided from top to bottom: 1) carbonate ooze "Seekreide". 2) dovegrey clayey muds; 3) dark "hydrotroillite" muds: 4) multicoloured oxirlized clayey mud. In iudividual zones the content of sandy-silty component is higher and it can form independent interbeds.
   The Holocene units Ib and Ia show a distinct lithofacies zoning related to the differentiation of two types of cementation – biogenic to the north and dominantly terrigenous to the south. The thickness of the Units increace with increasing terrigenous component. After the thickness reaches a critical value the marls grade to roqufort type (probably gas-hydrate).
   In the type development of uni lb the following packets were traced from top to bottom: 1) light·and loose sapropelic oozes, 2) dark compac t sapropel, 3) grey-green clayey muds (transi tional packet lb-c). In case of large content of terrigenous component, clayey and silty lithofacies may be divided. A wash-oul over large areas was established between units Ib and lc.
   Unit Ia in the type seclion is represented by carbonate coccolithic oozes. To the south clayey, silly and sandy lithofacies are divided. In the latter turbidites made up of material from the Anatolian province play a consider ablerole.