KrittPalæogen

KrittPalæogen is a provisional chronostratigraphic subdivision proposed for the Paleogene period to denote a brief interval around the Paleocene–Eocene boundary. The name is a combination of the local Kritt Basin lithostratigraphy and the standard Palæogen terminology, and it is intended as a regional, provisional unit rather than a globally ratified stage.

Definition and timeframe: Most proposals place KrittPalæogen at approximately 59 to 54 million years ago, spanning the latter part of the Paleocene and the earliest part of the Eocene. It is defined by distinctive fossil assemblages and sedimentological features, including shifts in mammalian lineages and associated floral changes, as well as rapid but short-lived climate fluctuations.

Stratigraphic context and evidence: Evidence comes from sedimentary sequences in the Kritt Basin and neighboring basins in Europe and North Africa, with correlations to magnetostratigraphy and calcareous nannofossil biostratigraphy. The unit is anchored by marker horizons that correspond to regional isotopic or biostratigraphic signals.

Fossil record and environment: The faunal assemblages indicate early mammalian diversification, including primates and early ungulates, alongside plants adapted to warm, greenhouse-type conditions with episodic cooling events. Deposits are commonly fluvial-lacustrine with interbedded coals and mudstones, reflecting a dynamic climate and mosaic landscapes.

Current status and reception: KrittPalæogen remains regional and provisional. It has not achieved formal status in the International Chronostratigraphic Chart and is primarily used in local stratigraphic syntheses and teaching materials. Widespread acceptance requires further correlation, dating, and peer-reviewed validation.

See also: Paleogene, Paleocene, Eocene, Chronostratigraphy.