Paleogeographic analysis of calcareous nannoplankton distribution in late cretaceous of southern Ukraine

Abstract

During the Early Cretaceous of the studied area had open access to thetic water masses and was closed from the north, which has led to the development of thermophilic nannoplankton. In particular, the wide development Nannoconaceaa unknown in boreal sediments.

As a result the Albian transgression since Cenomanian opens access to the boreal water masses through Russian sea that leads to the appearance of individual representatives nanocomplex coldwater communities.

Experiencing the greatest impact northern periphery of the studied areas: the north-west there is a relatively small penetration of boreal species across northern Europe (Repagulum parvidentatum, Mennerius cornuta, Axopodorhabdus albianus, Prolatipatella multicarinata, Seribiscutum primitivum, Polypodorhabdus madingliensis, Manivitella gronosa, Lucianorhabdus arcuatus, Gaarderella granulifera) and the north-east through the Konka - Yalynsk depression connection is established with the colder waters of the Russian Sea (Misceomarginatus plenoporus and Repagulum parvidentatum).

Also in southern territory in the Crimean Mountains in the Upper Cretaceous deposits across single tropical species: Uniplanarius trifidus, Quadrum gartneri and Micula mura.

For the first time climatic differentiation begins to appear even in Coniacian. Species Eiffeluthus eximius become numerous in the south, and the species Kamptnerius magnificus prevails in the north.

Climatic zones must be taken into account when drawing up and use of regional stratigraphic schemes.