New Fossil Localities and the Base of the Cambrian in Southeastern Newfoundland

Abstract

In the essentially continuous late Precambrian – Early Paleozoic succession of eastern Newfoundland, abundantly fossiliferous Cambrian shales are separated in most places from underlying strata by a quartzite-siltstone unit. This unit has been referred to the Random Formation in the Avalon-Bonavista area (east) and to the Blue Pinion Formation in the Fortune Bay area (west), and its age and significance in defining a Cambrian-Precambrian boundary have been in doubt for some time. An erosional disconformity at the top of the Random Formation has been interpreted as the base of the Cambrian by most authors. Recent stratigraphic studies indicate that both the Random and Blue Pinion Formations are parts of a laterally continuous lithologic unit and that the upper contact of this unit is gradational and conformable in central parts of its outcrop area. New fossil discoveries both within and beneath the Blue Pinion Formation indicate that the quartzite-siltstone unit is diachronous, and that its westernmost exposures are of Cambrian age.

Nick Rast and the recognition of the Avalonian Arc

“…Consistent with its interpretation as the stable southeastern margin of the Appalachian orogen, accounts of the Lower Paleozoic geology of the Avalon Platform by Williams (1964), McCartney (1967, Greene and Williams (1974) and others, described a Cambrian-Ordovician platformal succession dominated by shallow-marine siliciclastics and minor limestones. The Avalon Platform and its correlatives were also known to possess a distinctive ''Atlantic'' trilobite fauna that contrasted with the contemporary ''Pacific'' fauna of the Laurentian Platform (e.g., Cowie, 1974), as would be expected of the opposing margins of a major ocean.…”

The Avalon Zone: A Pan‐African terrane in the Appalachian Orogen of Canada

“…The stratigraphy and palaeontology of the Cambro-Ordovician succession of the Avalon Zone has been described in detail by a number of authers (e.g. Walcott 1900; Van Ingren 1914; Hayes and Howell 1937;Alcock 1938;White 1939;Hutchinson 1962;Rose 1952;Fletcher 1972;Butler and Greene 1974;Greene and Williams 1974) and, therefore, only a brief summary is given here. 1977).…”