The Bessarabian (Sarmatian) reef buildup between the village of Tyulenovo and Cape Shabla (Northeastern Bulgaria) as climatic and paleoecological indicator

The Bessarabian (Sarmatian) limestones composed mainly of endemic foraminifera Nubicularia novorossica are studied in detail in three sections between the village of Tyulenovo and Cape Shabla (Northeastern Bulgaria). An important reef buildup found in the upper levels of the sections allows to reconstruct the climatic and paleoenvironmental conditions. The most prominent changes are а shift from subtropical to drier climate and increased wave activity. This led to a decrease in the amount of Nubicularia novorossica and an increase in encrusting organisms such as encrusting nubicularia, bryozoans and red algae, which protected the newly formed sediments from destruction by the strong wave disturbance. The occurrence of less favorable climatic conditions is also evidenced by the presence of microbial micrite masses in the reef limestones.