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20 years of event stratigraphy in NW Germany; advances and open questions

Wiese F., Wood Ch. J., Kaplan U.

Acta Geologica Polonica

2004

Vol. 54, no. 4

639--656

The application of event stratigraphy in the Cenomanian to Lower Coniacian (Upper Cretaceous) Plńnerkalk Gruppe of northwestern Germany has advanced stratigraphic resolution considerably. For a short interval in the Upper Turonian, various genetically variable events (bioevents, tephroevents, stable isotope marker, eustatoevents) are reviewed and new data are partly added. In addition, the lateral litho and biofacies changes within individual events are discussed and provide a basis for a tentative high-resolution correlation between distal and proximal settings. The dense sequence of events permits a stratigraphic resolution of 50 - 100ky for some intervals. Beyond stratigraphic purposes, the alternation of fossil barren intervals with thin fossil beds still demands explanations. As taphonomic processes are considered to be play only a minor role, other explanations are required. It appears that trophic aspects and a calibration of planktic and benthic faunal assemblages may result in a better understanding of this biosedimentary system and its faunal characteristics.

Santonian ammonite stratigraphy of the Munster Basin, NW Germany

Kaplan U., Kennedy W.

Acta Geologica Polonica

2000

Vol. 50, no. 1

99-117

The upper Coniacian and Santonian ammonite stratigraphy of the Munster Basin, Westphalia, NW Germany, is described in the context of regional litho-, inoceramid- and sequence stratigraphy. The Sphenoceramus pachti & S. cardissoides Zone, previously regarded as basal Santonian, is placed in the uppermost Coniacian. The Lower Santonian corresponds to the Cladoceramus undulatoplicatus Zone, the lower Middle Santonian to the Cordiceramus cordiformis Zone. The Sphenoceramus pinniformis Zone spans the upper Middle Santonian to the lower Upper Santonian. The succeeding Sphenoceramus patootensiformis Zone corresponds approximately to the Marsupites testudinarius crinoid zone of the upper Upper Santonian. Occurrences of the belemnite Gonioteuthis are discussed. The ammonite occurrences are documented in the context of inoceramid and where possible, belemnite and crinoid stratigraphy. A Texanites (Texanites) pseudotexanus Zone extends from the uppermost M. subquadratus Zone to the Upper Coniacian/Lower Santonian boundary. The Kitchinites emscheris Zone comprises the Lower and Middle Santonian. The Upper Santonian corresponds to the Boehmoceras arculus Zone. The ammonite faunas are predominately endemic from the Upper Coniacian to the Middle Santonian. Only the Upper Santonianyields supraregional and even global ammonite taxa such as Boechmoceras arculus and B. krekeleri, which co-occur with the widespread crinoids Uintacrinus socialis and Marsupites testudinarius. Sequence boundaries, followed by transgressive pulses, are identified in the uppermost Coniacian, with a subordinate event in the Middle Santonian, the most significant event in the basal Upper Santonian and the last in the Lower Campanian. Ammonite occurrences are clearly related to the sequences recognized.