Planktonic Biota Constituents Responses to Global Sea-Level Changes Recorded in the Uppermost Albian to Middle Cenomanian Deep-Water Facies of the Outer Carpathians

Abstract

Interpretations of sea-level changes over geological time are mainly based on analyses of sediments deposited within stable platforms. One of the criteria for recognizing these changes is the composition of skeleton-bearing protists living in environments close to the shoreline and on the continental shelf. It can be assumed that the source of information about sea-level changes may also be found in assemblages of microfossils redeposited from the shelf to the marginal ocean basin. With such an assumption, this article presents an interpretation of changes in marine plankton communities (radiolarians and planktonic foraminifera), which during late Albian–middle Cenomanian were redeposited with carbonate mud by gravity currents from the peri-Tethyan shelf to the northern, marginal Silesian Basin of the Western Tethys. Planktonic biota identified in sediments deposited by gravity flows and those found in hemipelagic shales separating them, indicate that their composition may be correlated with eustatic changes in the sea level from the late Albian (KAl8) to middle Cenomanian (KCe3).