Foraminifera from the Late Jurassic and Early Cretaceous carbonate platform facies of the southern part of the Crimea Mountains, Southern Ukraine

Abstract

Upper Jurassic and Lower Cretaceous deposits of the Crimea Peninsula are rich in microfossils frequently used for stratigraphic interpretations. In case of foraminifera, the research has been carried predomi- nantly on assemblages obtained by washing the rock samples. The present paper is based on investigations of thin sections from the more indurated sediments that seldom were objects of study. Its goal was to obtain additional information on age and environment of sediments studied. Over 250 thin sections from 16 surface outcrops yielded abundant foraminifera from which over fourty are described herein. Many foraminiferal species (e.g., Labirynthina mirabilis, Parurgonina caelinensis, Neokilianina rahonensis, Amijella amiji, Anchispirocyclina lusitanica) are stratigraphically significant and known from the Kimmeridgian-Tithonian of the Mediterranean Tethys. The Early Cretaceous fauna is represented by Protopeneroplis ultragranulata, Everticyclammina kelleri, Nautiloculina bronnimanni, Monsalevia salevensis, and Mayncina bulgarica. Generally, the investigated fauna is typical for paleoenvironment of the carbonate platform. Older (Kimmeridgian-Tithonian) assemblages represent the inner, and younger (Berriasian) outer parts of the platform. Palaeogeographic distribution of many species described from the studied area indicates their affiliation with cosmopolitan biota known from the north Tethyan shelf. Additionally, few calcareous cysts of Dinoflagellata have been identified and described.