Albian

The Albian (often shortened in the German language to Alb, rarely also albien ) is in the earth's the name for a chronostratigraphic level in the highest Lower Cretaceous. The geochronological period extends from about 112.9 to about 100.5 million years ago. The Albian following the Aptian and is detached from the Cenomanian.

Naming and history

The stage was proposed in 1842 by Alcide Dessalines d' Orbigny and named after the French river Aube (Latin Albia ). The name of equality of geological stage Alb ( ium ) and the region name Swabian Alb and Franconian Alb due to chance.

Definition and GSSP

The base of the stage is defined by the first appearance of coccolithophores Type Praediscosphaera columnata, the end of the stage by the first appearance of foraminiferal species Rotalipora globotruncanoides. A GSSP (global type locality and type profile ) has not yet been finally determined.

Subdivision

For the Albian the lower grades lower, middle and Oberalbium are reported.

Regionally, the Albian is also still divided into the Lower School Gaultium and Vraconium.

Rocks of the Albs in Germany

A typical marine rock formation in Germany is the Flammenmergel example, in the region of the blind -well to the south of Lower Saxony.