Uppermost Cambrian and Lower Ordovician conodont biostratigraphy of the Survey Peak Formation (Ibexian/Tremadoc), Wilcox Pass, Alberta, Canada

Abstract

The Survey Peak Formation (350 m thick) consists of calcareous shale, mudstone, siltstone, and limestone-pebble conglomerate, and is formally divided into four revised members, successively: Basal Silty Member, Putty Shale Member, Middle Carbonate Member, and Upper Carbonate Member. The Wilcox Pass section, Jasper National Park, Alberta, provides a standard stratigraphic section for the southern Canadian Rocky Mountains and yielded over 4,500 conodonts from 87 samples which are of high species diversity, moderately well preserved, with a conodont Color Alteration Index (CAI) value of 3. Over 50 multielement species representing some 20 genera are identified, and most are illustrated. Conodont zones recognized in the four members include: Basal Silty Member—Eoconodontus notchpeakensis, Cordylodus proavus, C. caboti, C. intermedins, and C. lindstromi; Putty Shale Member—lower C. angulatus; Middle Carbonate Member—upper C. angulatus and coeval Rossodus manitouensis, Colaptoconus priscus (new) and Scolopodus cf. S. rex; Upper Carbonate Member—Striatodontus lanceolatus-S. striatus. In total, ten conodont lineage and assemblage zones are recognized within the Survey Peak Formation. Most can now be precisely correlated with trilobite faunas and acritarch microfloras described from this section, and with conodont zones established for the Great Basin area, Utah-Nevada, and for western Newfoundland. The Survey Peak Formation is of uppermost Cambrian to lower Ibexian (Tremadoc) in age with the Cambrian-Ordovician boundary placed between 26 and 29 m above the base of the formation in the Basal Silty Member.