Upper Cambrian (Furongian) biostratigraphy in Scandinavia revisited: definition of superzones

Abstract

The traditional Furongian trilobite biozones of Scandinavia, recently proposed abandoned due to inconsistent boundary definitions [Terfelt, F., Eriksson, M.E., Ahlberg, P. & Babcock, L.E., 2008: Furongian Series (Cambrian) biostratigraphy of Scandinavia – a revision. Norwegian Journal of Geology88, 73–87], are resurrected and elevated to superzonal rank. These superzones are usually readily recognized in the field, even by non-specialists, and for general correlation and mapping the more wide-ranging biozones are considerably more practicable than the very detailed zonation (formerly subzonation) introduced by Terfelt et al. (2008). Formal definition of the superzones is outlined including designation of stratotype sections. The superzones are each defined by the FAD of a characterizing species group and upwards delimited by the base of the succeeding superzone. The long used Olenus, Parabolina and Leptoplastus (super)zones as well as the recently introduced Acerocarina Superzone ( =  Acerocare Zone of older literature) are maintained and formalized. The Protopeltura praecursor, Peltura minor and Peltura scarabaeoides zones are abandoned and replaced by two new units, named the Protopeltura and Peltura superzones, respectively. Accordingly, all Furongian superzones have a uniform naming style referring to a characteristic genus. The six Furongian superzones currently comprise 27 trilobite zones. The Paradoxides forchhammeri Superzone (Cambrian Series 3) is extended upwards to the base of the Olenus Superzone, thereby formally including the Agnostus pisiformis Zone.

Keywords::

• trilobites
• biostratigraphy
• superzones
• Furongian
• Scandinavia

Acknowledgements

Reviewers Per Ahlberg, Lund, Sweden, and David L. Bruton, Oslo, Norway, are thanked for constructive comments improving the original manuscript.