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Refined correlations by means of lithostratigraphy and gadid otolith zonation of the Rupelian of the North Sea basin: a progress report
Gaemers, P.A.M. (1994). Refined correlations by means of lithostratigraphy and gadid otolith zonation of the Rupelian of the North Sea basin: a progress report. Bull. Belg. Ver. Geologie = Bull. Soc. Belg. Geol. 102(1-2): 147-157
In: Bulletin van de Belgische Vereniging voor Geologie = Bulletin de la Société Belge de Géologie. Belgische Vereniging voor Geologie = Société Belge de Géologie: Brussel. ISSN 0379-1807; e-ISSN 0772-9464, meer
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| Abstract |
The otolith zonation for the Rupelian (in wide sense, including the Late Tongrian Ruisbroek Sands) has been extended with five zones, comprising nine zones now. The new zones are mainly based on new members of the Parvicolliolus lineage. The frequency of otoliths in Rupelian sediments is usually low due to poor conditions in most marine environments. A high abundance of otoliths is often remarkable in horizons within the septaria clay with the highest concentrations of calcium carbonate in calcareous intervals and in calcareous beds intercalated in lime-free intervals. These highly calcareous beds usually also contain septaria nodules. The large numbers of otoliths in these beds are strong evidence of very reduced sedimentation rates and are additional proof of an original1y carbonate rich sedimentation in levels containing septaria. Correlation of the septaria levels has been established between the borehole for the storm weir and the boreholes for the underground railway under the River Scheldt at Antwerp. By this the "standard" septaria numbering system in Belgium is enlarged to 20 beds comprising S10 up to and including S160. Based on litho- and biostratigraphical data a new correlation between the "standard" septaria numbering and the septaria levels in the Winterswijk area in the eastern part of the Netherlands is proposed. The changes in the correlations lead to several conclusions, including the absence of a supposed hiatus between S70 and S80 at Kruibeke, the stratigraphically higher position of the probably larger local hiatus of the Aturia horizon at Winterswijk, the stratigraphically more extensive development of the septaria clay at Winterswijk and the lower sedimentation rates in the higher part of this clay there, and the clearly older age of the Kleine Spouwen Member (Nucula Clay) with respect to the base of the Terhagen Member. |
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