Biostratigraphy of the Jurassic-Cretaceous boundary layers from South Slovenia

Abstract

Aberrant tintinnids from the Dinarides of South Slovenia do not indicate the Valanginian stage as was recorded for many years. The author arrived at this decision after studying all the aspects of the occurrences of aberrant tintinnids. Along the old Vrhnika—Logatec road, for example, they occur in association with Clypeina jurassica indicating Upper Malmian series. Clypeina alone persists into the top Malmian layer. Elsewhere, however, tintinnids extend higher than Clypeina. The overlying limestone/dolomite alternation is of transitional character and is considered to be of Berriasian age. Only thereupon follows Valanginian stage characterized by the true Cretaceous index fossils of alga Clypeina? solkani Conrad & Radoičić and foraminiferal genera Cuneolina, Debarina, Pseudotextularia.