Albertiana Research Article: Stable carbon isotope record of carbonate across the Carnian–Norian boundary at the prospective GSSP section at Black Bear Ridge, British Columbia, Canada

Albertiana Research Article

Lei, J.Z.X., Husson, J.M., Golding, M.L., Orchard, M.J., & Zonneveld, J.-P. 2021. Stable carbon isotope record of carbonate across the Carnian–Norian boundary at the prospective GSSP section at Black Bear Ridge, British Columbia, Canada. Albertiana, vol. 46, 1–10.

Abstract – The Black Bear Ridge section is exposed on the shores of Williston Lake, British Columbia, Canada, with Late Triassic carbonate strata encapsulating the Carnian–Norian boundary as constrained by several fossil indices. Analysis of δ13Ccarb from this section reveals a six-meter-thick interval of increased instability proximal to the boundary. This excursion interval features anomalously low negative values, a shift of approximately -3 ‰ from the pre- and post- excursion interval values which average -0.95 ‰. It also features high point-to-point variability between these anomalously negative values and values comparable to the average outside of the excursion. This atypical feature of the excursion interval is interpreted to be the result of rapid, local-scale carbon cycle variation related to the global faunal turnover at the Carnian–Norian boundary, suggesting prolonged ecosystem instability around the stage boundary.

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