Ammonites in the Elly-3 well. A contribution to The Jurassic Petroleum System in the Danish Central Graben - The PETSYS Project

Finds of ammonites in a cored interval (depths: 3957–3982m / 12983’00”-13064’02”) are studied with the purpose of adding data to the biostratigraphy of the Elly-3 well (Fig. 1). 27 levels with ammonites were recorded within the interval (Table 1).

The Oxfordian was a time of pronounced faunal provincialism and separate zonations exists for different areas (Fig. 2). The zonation used in the Submediterranean (including e.g. Portugal, Spain, France, southern Germany and Poland) is considered the primary standard. A second zonation represents the Subboreal Province which is smaller and includes e.g. northernmost France, southern England, northern Germany i.e. getting close the Elly-3 well site. The Boreal ammonite zonation represents the most northerly province including e.g. Scotland, Greenland, Spitsbergen, Barents Shelf (Sykes & Callomon 1979). The ammonites in the studied interval of the Elly-3 well, are dominated by species of the genus Amoeboceras which is a characteristic Boreal form (Figs. 3–21; Table 1). The lowermost ammonite recorded may represent the A. glosense Zone (c. 3982m) and the ammonites in the overlying succession (3979.8–3972m, perhaps up to 3959.6m) demonstrate the presence of the A. serratum Zone and the A. rosenkrantzi Zone. The studied interval thus belong to the upper Middle – Upper Oxfordian