An Arenig graptolite from Bell Island, eastern Newfoundland - its biostratigraphic and paleogeographic significance

Authors

  • S. Henry Willams Department of Earth Sciences, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X5, Canada

DOI:

https://doi.org/10.4138/1692

Abstract

An interval of dark grey silts and shales within the Youngsters Gulch Member of the Powers Steps Formation (basal Wabana Group) on Bell Island, eastern Newfoundland yields a monospecific graptolite assemblage consisting of Didymograptus (sensu lato) simulans Elks and Wood. This species has hitherto been recorded only from Great Britain and Bohemia, with possible specimens from China, thus lending support to the currently accepted paleogeographic reconstruction of Newfoundland in the Ordovician. The occurrence of D. (s.l.) simulans permits accurate biostratigraphic correlation of the Powers Steps Formation with equivalent Norm American and European sequences. The formation is of early/middle Arenig age, equivalent to Bed 11 of the Cow Head Group of western Newfoundland, to part of the D. deflexus or D. nitidus zones of northern England and to the lower part of the Arenig Series of Arennig Fawr, Norm Wales. RÉSUMÉ Un intervalle de siltites et de shales gris fencé au sein du Membre de Youngsters Gulch dans la Formation de Powers Steps (base du Groupe de Wabana) sur l'ile Bell (Terre-Neuve orientale) à livré un assemblage monospécifique de graptolites appartenant au taxon Didymograptus (sensu lato) simulans Elks and Wood. Jusqu'à présent, on n'avait documenté la présence de cette espèce qu'en Grande-Bretagne et en Boheme, avec des représentants possibles en Chine. Le tout corrobore la situation paléogéographique de Terre-Neuve durant l'Odovicien telle qu'admise courammenL La présence de D. (s.l.) simulans permet une corrélation biostratigraphique exacte entre la Formation de Powers Steps et les unités équivalences en Amerique du Nord et en Europe. La formation date du début ou du milieu de l’Arenig, ce qui Iquivaut au Lit 11 du Groupe de Cow Head (Terre-Neuve occidentale), tune parté des zones L’D. deflexus ou D. nitidus (Angleterre septentrionak),ainsiqu'k la portion inférieure de la Serie d*Arenig à Arennig Fawr (Pays de Galles septentrional). [Traduit par le journal]

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Published

1990-03-01

How to Cite

Willams, S. H. (1990). An Arenig graptolite from Bell Island, eastern Newfoundland - its biostratigraphic and paleogeographic significance. Atlantic Geoscience, 26(1). https://doi.org/10.4138/1692

Issue

Vol. 26 No. 1 (1990)

Section

Articles

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