Boltysh astrobleme (impact structure): Where? When? As?

Dykan, KV
Dykan, NI
Dopov. Nac. akad. nauk Ukr. 2020, 2:52-57
https://doi.org/10.15407/dopovidi2020.02.052
Section: Geosciences
Language: Ukrainian
Abstract: 

For the first time, numerous remains of fossil ostracods (genera Cytherella, Cypridea, Clithrocytheridea, Mongolianella, Rhinocypris, Bairdopillata, Schuleridea, Polycope, Langtonia, Macronotella) are found in sediments of the Boltysh impact structure (Ukraine).The time of the Boltysh impact event (at the end late Maastrichtian or at the beginning of the early Paleocene), the age of the lower part of sediments of the Boltysh impact structure that formed at the beginning of the Boltysh Crater formation (int. 463–415 m) and the time of formation of the water basin (early Paleocene), reconstruction of physical and geographical conditions of the early Boltysh reservoir are established by ostracods. Model of the relationship of the Boltysh reservoir with the sea at the beginning of its creation as a “lake on the shore of the ocean” was proposed too. The Boltysh basin was a large deep lake close to the oligotrophic or oligo-mesotrophic type with high specific mineralization of water. Migration of sea ostracods from the Tethys Ocean into the lake in the early Paleocene occurred through a small strait, the water exchange between the lake and the ocean was periodic with varying intensity and duration.

Keywords: Boltysh impact structure, ostracods, Paleogene, paleogeography
References: 

1. Kelley, S. P. & Gurov, E. (2002). Boltysh, another end-Cretaceous impact. Meteorit. Planet. Sci., 37, Iss. 8, pp. 1031-1044. Doi: https://doi.org/10.1111/j.1945-5100.2002.tb00875.x
2. Gurov, E. P. & Gozhik, P. F. (2006). Impacted crater formation in the history of the Earth. Kyiv: Institute of Geological Sciences of the NAS of Ukraine (in Russian).
3. Ebinghaus, A., Jolley, D. W., Andrews, S. D. & Kemp, D. B. (2017). Lake sedimentological and ecological response to hyperthermals: Boltysh impact crater Ukraine. Sedimentology, 64, pp. 1465-1487. Doi: https://doi.org/10.1111/sed.12360
4. Jolley, D., Gilmour, I., Gurov, E., Kelley, S. & Watson, J. (2010). Two large meteorite impacts at the Cretaceo us–Paleogene boundary. Geology, 38, pp. 835-838. Doi: https://doi.org/10.30836/igs.1025-6814.2018.3.142276
5. Dykan, N. (2017). Ostracods of posr-crater sediments sy the Boltysh impact structure (Ukrainian Shield). Collection of Scientific works of the IGS NAS of Ukraine, 10, pp. 37-49 (in Ukrainian). Doi: https://doi.org/10.30836/igs.2522-9753.2017.142036
6. Dykan, N., Kovalchuk, O., Dykan, K., Gurov, E., Dašková, J., Přikryl, T. (2018). New data on Paleocene–Eocene fauna (gastropods, ostracods, fishes) and palynoflora of the Boltysh impact structure (Ukraine) with biostratigraphical and palaeoecological inferences. N. Jb. Geol. Paläont. Abh., 287/2, pp. 213-239. Doi: https://doi.org/10.1127/njgpa/2018/0714
7. Ceolin, D., Fauth, G. & Coimbra, J. C. (2011). Cretaceous – Lower Paleogene ostracods from the Pelotas Basin, Brazil. Palaeobio. Palaeoenv., 91, No. 2, pp. 111-128. Doi: https://doi.org/10.1007/s12549-010-0041-1