Middle Ordovician conodonts from the Buchans Group, central Newfoundland, and their significance for regional stratigraphy of the Central Volcanic Belt: Discussion

Nowlan and Thurlow have recently reported a conodont fauna of latest Arenig early Llanvirn age from the Buchans Group, central Newfoundland, and have suggested that this demonstrates that all volcanogenic massive sulfide deposits and, hence, associated volcanism in the Canadian Appalachians are of Caradocian or older Ordovician age. They go on to state that this requires substantial revisions of models for the northern Appalachians. We welcome this important contribution to the knowledge regarding the age of Roberts Arm Volcanic Belt (which includes the Buchans Group; Dean 1977) but find their suggestion that current models for central Newfoundland are inadequate or erroneous to be somewhat misleading. Perhaps this is the case if the tectonic models they are referring to are those, for instance, of Dean (1977, 1978), Strong (1977), or Dean and Kean (1980). However, their results strongly support the models set out by Kidd et al. (1977),