Albertiana Research Article
Orchard, M.J. 2019. The Carnian-Norian GSSP candidate at Black Bear Ridge, British Columbia, Canada: update, correlation and conodont taxonomy. Albertiana, vol. 45, 50–68.
Abstract – Re-assessment of conodonts from the Carnian-Norian boundary (CNB) at Black Bear Ridge (BBR), British Columbia and Pizzo Mondello (PM), Sicily improves correlation. Fossil endemism is less of a problem than are differing taxonomic approaches. Re-evaluation of literature suggests that most platform genera differentiated at BBR can also be recognized at PM. These are Carnepigondolella, Ancyrogondolella, ?Kraussodontus, Metapolygnathus, Norigondolella, Parapetella, Primatella, and Quadralella. Only Acuminatella at BBR is endemic, whereas use of Hayashiella and Paragondolella at PM is discounted. Hence, faunal turnovers PM-T1 and PM-T3 are not strongly endemic. Standardization of the conodont nomenclature facilitates improves correlation of the two GSSP candidates: top Carnepigondolella samueli Zone at BBR is equivalent to a position within the “Epigondolella” vialovi Zone at PM; the Primatella primitia Zone can be recognized in both sections; correlation of the Metapolygnathus parvus Subzone is strengthened by 14 new conodont identifications at PM, including relatives of the Pr. gulloae Zone index; the lower Norian succession of Ancyrogondolella quadrata succeeded by An. triangularis, well-known in western Canada, appears corrupted at PM.
The FAD of Metapolygnathus parvus alpha morphotype can be correlated between sections, as can the simultaneous demise of typical Carnian taxa. At BBR, the concurrent appearance of diminutive conodont species corresponds to geochemical excursions implying anoxia and a temperature maximum during the Me. parvus Subzone. Within 1 m above this datum, the FAD of other fossil proxies occur, including an array of conodonts, the bivalve Halobia austriaca, and the ammonoid Pterosirenites sp.. The Me. parvus Subzone corresponds to the uppermost part of the traditional Carnian ammonoid zone of Klamathites macrolobatus.