Calcareous nannoplankton from broad Burdigalian/Langhian boundary interval in the Paratethys area
| Thesis title in Czech: | Vápnitý nanoplankton z širšího hraničního intervalu burdigal/langh v Centrální Paratetydě |
|---|---|
| Thesis title in English: | Calcareous nannoplankton from broad Burdigalian/Langhian boundary interval in the Paratethys area |
| Key words: | vápnitý nanoplanktón, Miocén, biostratigrafie, paleoekologie, Paratetyda |
| English key words: | calcaresou nannoplankton, Miocene, biostratigraphy, paleoecology, Paratethys |
| Academic year of topic announcement: | 2017/2018 |
| Thesis type: | dissertation |
| Thesis language: | angličtina |
| Department: | Institute of Geology and Paleontology (31-420) |
| Supervisor: | prof. RNDr. Katarína Holcová, CSc. |
| Author: |
| Preliminary scope of work in English |
| The proposed project is focused on processes in the Burdigalian/Langhian boundary interval in the non-oceanic realm. The base of Langhian has not been standardized yet and remains one of the key objectives of the Neogene Subcommission of the International Commission of Stratigraphy. Candidates for stratotypes are situated in the Mediterranean area that directly communicated with Paratethyan realm. This fact speaks in favour of Paratethys area to test applicability of proposed stratigraphical markers in extra-Mediterranean non-oceanic area. The Burdigalian/Langhian boundary is recently proposed at 15.974 Ma, which is the top of polarity Chron C5Cn.1n. Calcareous nannoplankton Zone boundary (NN4/NN5 Zones) astronomically calibrated at 14.91 Ma positioned it, in fact, within the Langhian. Therefore, several different calcareous nannoplankto events have been proposed as biostratigraphic markers of the Burdigalian/Langhian boundary: the Highest Common Occurrence of Helicosphaera ampliaperta and the paracme of Sphenolitus heteromorphus. The abundance peak of H. ampliaperta is slightly younger (15.899± 0.024 Ma). However, all proposed events occurr probably only locally in the Mediterranean area, reflect local paleoenvironmental condition and cannot be used for interregional correlation. In the Central Paratethys area, no clear calcareous nannoplankton events have been defined yet in this interval. The interval is less known and no detailed quantitative biostratigraphical data exist. Because composition of calcareous nannoplankton assemblages reflects quality of superficial water and paleooceanographic circumstances (circulation regime), we expect events recording effect of climatic and paleogeographic evolution on calcareous nannoplankton assemblages. The influence of Middle Miocene Climatic Optimum and Mi-2 and Mi-2a global cooling events is expected. Also influence of significant paleogeographical event – closure of Indic-Mediterranean gateway (14.5-16 Ma) as well as changes in Mediterranean-Paratethyan gateway due to intensive tectonic (Styrian phase) is expected. |