Diagenetic features of limestones from the Cretaceous/Tertiary boundary of SW Slovenia (Yugoslavia)

Abstract

The Upper Cretaceous limestones show commonly syntaxial overgrowth on echinoid fragments, geopetal fillings with vadose silt, gravitational cements, neomorphic altered miliolids, and microsparite and pseudosparite. All features are indicative of a strong early freshwater diagenesis. In the Kozina beds minor hints for a freshwater diagenesis are present. In general a trend from freshwater influenced limestones to normal marine limestones can be observed. Birdseyes occur commonly with dedolomite. Additionally molds, vugs, and geopetal microsparitic silt is present. The Miliolid limestones generally were formed under normal marine lagoonal conditions. Only very locally hints for a weak early diagenetic freshwater influx are given. Scarce syntaxial overgrowth on echinoid fragments and some clear fine granular cements can be observed. Microcodium was commonly formed in local areas of short time emersion.