Chitinozoan biozonation in the upper Katian and Hirnantian of the Welsh Basin, UK

T. J. Challands*, T. R A Vandenbroucke, H. A. Armstrong, J. R. Davies

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

Here we present a chitinozoan biostratigraphical framework for the South Wales upper Katian and Hirnantian (Ashgill) succession. The current study indicates that three of the six Avalonian Ashgill chitinozoan biozones are recognised in the Welsh Basin; the bergstroemi, fossensis and umbilicata biozones. The Baltoscandian and Laurentian Hercochitina gamachiana biozone is suggested by the presence of Belonechitina cf. gamachiana and the Spinachitina taugourdeaui biozone is suggested by Spinachitina cf. taugourdeaui. Intervening between these is a newly erected lower Hirnantian regional biozone, the Belonechitina llangrannogensis n. sp. biozone. The late Katian (Cautleyan-Rawtheyan) Conochitina rugata biozone was not recognised, though the index taxon is recorded. The presence of B. cf. gamachiana below the lithological expression of the Hirnantian glacial maximum and alongside Rawtheyan graptolite and trilobite assemblages shows that the local base of the B. cf. gamachiana biozone lies beneath the Katian-Hirnantian boundary. Although at present in open nomenclature, the finds of B. cf. gamachiana and S. cf. taugourdeaui, from sites where these chitinozoans co-occur with graptolites, are potentially important; the area offers the potential to study how B. cf. gamachiana and S. cf. taugourdeaui are taxonomically and stratigraphically linked to the original index species. A composite Katian-Hirnantian chitinozoan biozonation for the Welsh Basin is presented and three new species are defined: Belonechitina llangrannogensis n. sp., Belonechitina ceregidionensis n. sp. and S. pinachitina penbryniensis n. sp.

Original languageEnglish
Pages (from-to)1-21
Number of pages21
JournalReview of Palaeobotany and Palynology
Volume210
DOIs
Publication statusPublished - 1 Jan 2014

Keywords

  • Avalonia
  • Chitinozoan
  • Hirnantian
  • Katian
  • Ordovician
  • Welsh Basin

Fingerprint

Dive into the research topics of 'Chitinozoan biozonation in the upper Katian and Hirnantian of the Welsh Basin, UK'. Together they form a unique fingerprint.

Cite this