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The Hectoroceras kochi Zone (Ryazanian) in the North Sea Central Graben and remarks on the Late Cimmerian unconformity
| Birkelund, T., Clausen, C.K., Nohr Hansen, H. and Holm, L. | |
| 1983 | |
| Danm. Geol. Unders. +rborg 1982:53-72, Kobenhavn 1983 | |
| The Hectoroceras kochi Zone (Ryazanian) in the North Sea Central Graben and remarks on the Late Cimmerian unconformity |
Birkelund, T., Clausen, C.K., Nohr Hansen, H. and Holm, L., 1983; The Hectoroceras kochi Zone (Ryazanian) in the North Sea Central Graben and remarks on the Late Cimmerian unconformity. Danm. Geol. Unders. +rborg 1982:53-72, Kobenhavn 1983 Abstract: Ammonites, inoceramids and dinoflagellate cysts found in core material from the E-1 well in the Tail End Graben of the Danish part of the Central Graben are described. The core belongs to the upper, highly radioactive part of the Kimmeridge Clay Formation (unit J-4) and includes the ammonite Hectoroceras kochi indicating the basal Cretaceous, Lower Ryazanian H. kochi Zone. Dinoflagellates indicate the Cannosphaeropsis thula Subzone. Dinoflagellates from cuttings immediately below and above the boundary between the Kimmeridge Clay Formation and the overlying Valhall Formation indicate a Valanginian age for the boundary (Spiniferites ramosus Zone). No hiatus between the two formations is discernible in the dinoflagellates. The "Late Cimmerian unconformity" is discussed in the light of the new stratigraphic data from the well. Dinocysts by H.N.H.