8th International Nannoplankton Association Conference
Upper Cretaceous deposits of the Ukraine are widely spread. They are represented by calcareous rocks, such as chalks, marls, calcareous clays and sands, reaching 2400m on the Black Sea shelf. Calcareous nannoplankton from the deposits have been studied since 1962 (by Shumenko) but the first nannofossil biozonation scheme was built in 1978 (by Shumenko & Stezenko) for the Crimean Mountain area. The Dnieper-Donetz depression was the next region where nannoplankton zonation was worked out. It was made by Lul'yeva in 1980. Also, such schemes were built for the regions of the Donetz Coal Fields in 1992 (by Shumenko) and the South Carpathians in 1991 (by Romaniv) (Figure 1).
The nannoplankton biozonation scheme for the Black Sea shelf is here proposed first. It is given in comparison with those schemes erected before. Having used the recent nannoplankton biozonation scheme of Burnett, we have got to subdivide the Upper Cretaceous deposits of the shelf into 14 zones. They are distinguished on the first and last occurrence (FO, LO) principles. Investigations were made on the PZO microscope (Poland).
Gartnerago segmentatum, Eiffellithus eximius, Micula staurophora, Lucianorhabdus cayeuxii, Arkhangelskiella cymbiformis, Broinsonia parca parca and Lithraphidites quadratus biozones are distinguished on the principle of the FO. Helenea chiastia and Uniplanarius trifidus biozones are distinguished on their LOs. Eiffellithus turriseiffelii is one which starts in the Albian. Lithraphidites acutus corresponds to the interval of Lithraphidites acutus extension. The lower boundary of the Broinsonia parca constricta zone is made on the LO of Eiffellithus eximius, and the extinction of Broinsonia parca constricta is the mark of the upper boundary of the zone. Also, two intervals of layers are distinguished: in the Lower Turonian there are layers with Gartnerago segmentatum and Kamptnerius magnificus, and in the Lower Maastrichtian, including the lowermost Upper Maastrichtian, layers of low-diversity assemblages are placed (Figure 1).
So, the previous data of nannofossil biostratigraphy of the Ukraine and the obtained ones give the good opportunity for correlating single-aged deposits within the Ukraine and the world in whole. Besides, they show the main nannofossil events during the Upper Cretaceous, regionally. The definite provinces in nannoplankton distribution can be distinguished.
Afterwards, it should be noted that the Black Sea shelf needs more-detailed biostratigraphic division, and the opportunities of nannofossil biostratigraphy are still available.
Copyright © 2000, most recent revision July 26, 2000Tania Hildebrand-Habel (firstname.lastname@example.org)