Dinocysts

Selected dinocysts and their occurrence in the geological past Source: BGR

Organic-walled dinoflagellate cysts, or dinocysts, are formed by unicellular protists that have existed mainly in marine but also in fresh water environments from about 210 million years ago (Upper Triassic) up to the present day. Due to their relatively short life spans and the broad regional distribution patterns of specific species, the application of this fossil group for the biostratigraphical dating of sediments has increased significantly in recent years.

As dinocysts are microscopically small (average size 0,05–0,1 mm), one sediment sample as small as a matchbox can contain many thousands to millions of dinocyst specimens.

Due to their very resistant organic walls, dinocysts are not destroyed by processes which may lead, for example, to calcite dissolution. This characteristic is of special importance for the analysis of sediments which contain no carbonate at all.

The study of dinocysts, in addition to that of other organic-walled microfossils such as pollen and spores, is generally referred to as palynology.

At BGR dinocysts provide important information regarding age classification of Campanian to Pleistocene sediments.

Importance of dinocysts from the Cenozoic of Germany

Dinocysts are the most important microfossil group, because

• species of planctonic foraminifera, calcareous nannoplankton and bolboforma are most commonly used for international stratigraphic correlation in the Cenozoic. However, these microfossil groups are only sporadically present in Tertiary sediments from Germany. Besides relatively unfavourable ecological conditions (shallow water, fluctuating salinities, occasionally high terrigenous input), calcareous dissolution is generally responsible for the absence of these organisms.

• other microfossil groups, such as benthic foraminifera, only allow a relatively rough biostratigraphic subdivision and correlation in north-western Europe. Pollen and spores, ostracodes and molluscs are also of limited use for the international correlation of Tertiary sediments. Dinocysts, however, are almost always present in the brackish to fully marine sediments of Germany and north-western Europe.

Therefore, dinocysts represent the most important micropaleontological tools for the dating of sediments in north-western Europe. They allow a very detailed and precise age designation which can be easily fitted to the international geological time scale. Correlation of dinocyst zones with the international time scale and with calcareous nannoplankton zones (PDF, 33 KB)

The Stratigraphic distribution of Paleogene and Miocene dinocysts in Germany (PDF, 464 KB) of more than 350 Paleogene and Miocene dinocyst species in Germany, which have been published during the last 35 years, were compiled by Köthe & Piesker (2007). This work is continued.

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References

Köthe, A. (2003): Dinozysten-Zonierung im Tertiär Norddeutschlands. – Revue Paléobiologie, 22(2): 895-923, 27 figures, 3 tables, 7 plates; Geneve.

Köthe, A. (2005): Korrelation der Dinozysten-Zonen mit anderen biostratigraphisch wichtigen Mikrofossilgruppen im Tertiär Norddeutschlands. – Revue Paléobiologie, 24(2): 697-718, 18 figures; Geneve.

Köthe, A. & Piesker, B. (2007): Stratigraphic distribution of Paleogene and Miocene dinocysts in Germany. – Revue Paléobiologie, 26(1): 1-39; Geneve.