The Sinemurian ammonoid succession of the Queen Charlotte Islands is subdivided into, in assending order, the Canadensis Zone, the "Coroniceras", Arnouldi, Varians, Harbledownense, and Tetraspidoceras assemblages. The Hettangian-Sinemurian boundar is drawn within the Canadensis Zone, at the first appearance of Badouxia columbiae and Metophioceras div. sp. The Sinemurian-Pliensbachian boundary has not yet been satisfactorily defined as the Tetraspidoceras Assemblage contains elements with both Sinemurian and Pliensbachian affinities. Correlation with the northwest European Standard Zonation as well as with the Mediterranean Province and South America is possible but often ambiguous. The present scheme contributes to the development of a Standard ammonite Zonation for North America.
- Hettangian-sinemurian boundary
- Queen charlotte islands
ASJC Scopus subject areas
- Space and Planetary Science