Dinoflagellate biostratigraphy of the Maastrichtian to Danian interval in the U.S. geological survey Albany core, Georgia, U.S.A.

Abstract

Dinoflagellate assemblages are used to delineate three intervals within the upper Ripley Formation and Providence Sand (Maastrichtian), and the lower Clayton Formation (Danian) in the U.S. Geological Survey Albany core, located near Albany, Georgia. Interval A is interpreted as early Maastrichtian in age, interval B is late Maastrichtian, and interval C is early Danian, based on comparisons with dinoflagellate cyst zonations from the type Maastrichtian and Danian regions. Comparison with a dinoflagellate cyst zonation from the Maastrichtian Severn Formation of Maryland indicates that the lower Severn is correlative with the upper Ripley and lower Providence, and that the upper Severn is correlative with the upper Providence. The Cretaceous‐Tertiary boundary is marked by a minor turnover in organic‐walled phytoplankton species. Some of the uppermost Maastrichtian and lowest Danian may be missing from the section. Variations in the relative abundances of Spiniferites and Manumiella see‐landica indicate a shallowing of the marine environment through the Maastrichtian. The species Manumiella druggii is considered to be a junior synonym of Manumiella seelandica.