Gosau Group

The Gosau Group (German: Gosau-Gruppe) is a geological stratigraphic group in Austria, Germany and western Slovakia and Romania whose strata date back to the Late Cretaceous to Eocene. It is exposed in numerous sporadic isolated basins within the Northern Calcareous Alps. It is divided into two subgroups, the Lower Gosau Subgroup which dates from the Turonian to Campanian, approximately 90 to 75 Ma and the Upper Gosau Subgroup which dates to the Santonian to Eocene, about 83.5 to 50 Ma.

The formations within each subunit vary significantly between basins. The thickness of the unit varies in but in the Gosau Basin it is over 2,300m thick. The sequence is largely marine, but the Grünbach Formation represents a terrestrial deposit and to the south-west of Vienna coal deposits in the Gosau have been worked. Many of the units of the group are fossiliferous, typically providing marine fossils such as ammonites, though terrestrial remains including those of dinosaurs are known from the Grünbach Formation and Schönleiten Formation.

Stratigraphic contacts between the Gosau beds and any earlier units are generally unconformable and the isolated pockets in which they occur are often fault bounded. Because the Gosau Group is a lithostratigraphic unit the time of deposition (in Ma before present) may be somewhat variable from place to place but they can be dated by their fossil content and the younger Gosau beds can also be distinguished from those which are older than lower Campanian by the assemblage of 'heavy minerals' they contain.