Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

Geological Magazine

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by COPE, J. C. W. Search for Related Content GeoRef GeoRef Citation

Correlation problems in the Kimmeridge Clay Formation (Upper Jurassic, UK): lithostratigraphy versus biostratigraphy and chronostratigraphy

Department of Geology, National Museum of Wales, Cathays Park, Cardiff CF10 3NP, UK

^* E-mail: john.cope{at}museumwales.ac.uk

A scheme of grouped lithostratigraphical units (‘beds’) proposed for the English Upper Jurassic Kimmeridge Clay Formation has been claimed to be also chronostratigraphical, but some of the resulting time-correlations conflict with those of the standard chronozonation based on ammonite biostratigraphy. Review of some critical ammonite species reaffirms the validity of the ammonite zonal scheme and shows that mismatching of lithologies (facies-correlations) has led to incorrect time-correlations. Because the numbering scheme of ‘beds’ was based on correlations of attenuated successions, it is on too coarse a time-scale to identify many non-sequences, and its usefulness as a chronostratigraphical tool is questioned. Evidence suggests that at least some calcareous concretions in the Kimmeridge Clay formed at shallow depths, which is relevant to discussions of the succession in terms of basin analysis.

Key Words: correlation • lithostratigraphy • biostratigraphy • chronostratigraphy • Kimmeridge Clay Formation • concretions