Professor Emeritus John Taylor, along with colleague Justin Strauss (Dartmouth) and IUP alumnus John Repetski ’69 (US Geological Survey), published a new study based on faunal collections from a 50-meter interval of the Jones Ridge Limestone in easternmost Alaska. The study provided new, detailed faunal range data across the base of the North American Ibexian Series and geochemical data that confirm an associated shift in ocean chemistry.
Notably, the study identifies a thin, previously undetected negative carbonate carbon (δ13C) isotopic excursion, designated the Basal Ibexian Negative Excursion (BINE), that is confined to a newly established Strictagnostus? sp. Subzone of the Ptychopleurites trilobite zone. The data collected in the study suggest that this interval represents a lowstand depositional package formed during an earlier Ibexian sea-level drawdown that created a widespread disconformity in shallower water deposits throughout Laurentian North America. In addition to its isotopic and stratigraphic contributions, the study introduces two new trilobite species, Ptychopleurites myrowi and Symphysurina ripperdani, alongside several others that are likely new, but left in open nomenclature. The research highlights the importance of integrating faunal, sedimentologic, and geochemical data in evaluating extinction events and their potential drivers.
Full citation: Taylor, J.F., Strauss, J.V., and Repetski, J.E., 2025, Late Furongian arthropod and conodont fauns and a new basal Ibexian (uppermost Cambrian Stage 10) isotopic excursion in the Jones Ridge Limestone of Alaska, Australasian Palaeontological Memoir 57, p. 491-520.
