Calcareous nanoplankton of Cretaceous sediments of Bahchisaray area of the South-Western Crimea

The calcic nannoplankton of the Cretaceous deposits of the Bakhchsarai region of the South-Western Crimea was studied. In the Lower Cretaceous, it is extracted from the Rezan and Biasala Formations, in the Upper Cretaceous — from the Belogorsk, Prokhladnoye and Kudrino Formations. The age of the enclosing sediments by calcareous nannoplankton has been specified. In the Rezan Formation, the nannoplankton zone is not singled out; in the Biasala Formation, apparently, part of the NC5 zone is present. In the Belogorsk Formation, the UC3 zone, subzone b, is allocated (partially), in the Kudrino Formation — the UC20 zone, and the UC20b subzone. Upper and lower boundaries of the zones are not traced.

Maastrichtian-Danian boundary deposits of the Central Crimea: new data on calcareous nanoplankton

Information on the structure features as well as new data on the distribution of calcareous nanoplankton (NP) from the Cretaceous-Paleogene boundary deposits of the Central Crimea is given. There is a rich complex of Cretaceous NP in both Maastrichtian and Danian rocks. Danian NP is sparse, poor preserved or absent. Lower Maastrichtian species Tranolithus orionatus (=Tranolithus phacelosus Stover) unknown in the Upper Maastricht of European sections and described only from the Upper Maastricht of the South-West of Tunisia is noted in Upper Maastrichtian rocks of studied area. Zones NP2–NP4 were determined in Danian rocks. The question of paleogeography is also concerned.

The calcareous nanoplankton in the Upper Paleocene deposits from Bakhhisaray region (South-Western Crimea)

The calcareous nannoplankton of the Upper Paleocene and Eocene deposits from Bakhchisaray region of the South-Western Crimea was studied, it comparison with the coeval complexes studied earlier was made and zones were identified. Kacha Formation corresponds to zones NP6–NP8 (?), Bakhchsarai Formation — to NP12 zone, Simferopol Formation — to zones NP13–NP14. According to the species composition, it was found that the calcareous nannoplankton lived in the normal-salt shelf sea, in the tropical belt.

Stratigraphic calibration of Oligocene–Miocene organic-walled dinoflagellate cysts from offshore Wilkes Land, East Antarctica, and a zonation proposal

There is growing interest in the scientific community in reconstructing the paleoceanography of the Southern Ocean during the Oligocene–Miocene because these time intervals experienced atmospheric CO2 concentrations with relevance to our future. However, it has remained notoriously difficult to put the sedimentary archives used in these efforts into a temporal framework. This is at least partially due to the fact that the bio-events recorded in organic-walled dinoflagellate cysts (dinocysts), which often represent the only microfossil group preserved, have not yet been calibrated to the international timescale. Here we present dinocyst ranges from Oligocene–Miocene sediments drilled offshore the Wilkes Land continental margin, East Antarctica (Integrated Ocean Drilling Program (IODP) Hole U1356A). In addition, we apply statistical means to test a priori assumptions about whether the recorded taxa were deposited in situ or were reworked from older strata. Moreover, we describe two new dinocyst species, Selenopemphix brinkhuisii sp. nov. and Lejeunecysta adeliensis sp. nov., which are identified as important markers for regional stratigraphic analysis. Finally, we calibrate all identified dinocyst events to the international timescale using independent age control from calcareous nanoplankton and magnetostratigraphy from IODP Hole U1356A, and we propose a provisional dinoflagellate cyst zonation scheme for the Oligocene–Miocene of the Southern Ocean.