Revised stratigraphy of the Cookson Group of southwestern New Brunswick and adjacent Maine

Authors

  • L. R. Fyffe Mineral Resources, Department of Natural Resources and Energy, P.O. Box 6000, Frederirton, New Brunswick E3B 5H1, Canada
  • J. Riva Department of Geology, University Laval, Ste-Foy, Quibec G1K 7P4, Canada

DOI:

https://doi.org/10.4138/1709

Abstract

The Ordovician Cookson Group in southwestern New Brunswick is divided into formations previously recognized in the adjacent area of Maine. However, the stratigraphic order of these formations is revised based on new fossil evidence. From the base upward, the revised Cookson Group comprises the Calais, Woodland, Pocomoonshine Lake, and Kendall Mountain formations; the latter formation contains newly discovered Caradocian graptolites. The Digdeguash Formation, previously assigned to the Silurian, is now included in the Cookson Group, and is considered to be equivalent to the Woodland and Pocomoonshine Lake formations on the basis of lithological similarities. The contact between the Digdeguash Formation and the Silurian Flume Ridge Formation, previously interpreted to be gradational, is a major fault RÉSUMÉ Le Groupe de Cookson du sud-ouest du Nouveau-Brunswick est divisé en formations a déjà que l’on identifiées dans la région adjacente du Maine. Cependant l'ordre stratigraphique de ces formations a été révisé suite à la decouverte d'un nouveau site fossilifere. A partir du bas, le Groupe de Cookson révisé comprend les formations de Calais, Woodland, Pocomoonshine Lake et de Kendall Mountain; cette demiere contient des graptolites nouvellement découverts appartenant à l'Ordovicien moyen (Caradocien). La Formation de Digdeguash, antérieurement considérée comme faisant partie du Silurien, est maintenant intégrée au Groupe de Cookson. La Formation de Digdeguash représente un faciès similaire à celui des formations Woodland et Pocomoonshine Lake. La zone de contact entre la Formation de Digdeguash et la Formation de Flume Ridge, d'âge silurien, antérieurement considérée comme graduelle est, en effet, une fait importante. [Traduit par le journal]

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Published

1990-11-01

How to Cite

Fyffe, L. R., & Riva, J. (1990). Revised stratigraphy of the Cookson Group of southwestern New Brunswick and adjacent Maine. Atlantic Geoscience, 26(3). https://doi.org/10.4138/1709

Issue

Vol. 26 No. 3 (1990)

Section

Articles

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