THE HIGH HEAD MEMBER TRACE FOSSILS OF NOVA SCOTIA, CANADA: A REMARKABLE ASSEMBLAGE OF LOWER CAMBRIAN DEEP-WATER ICHNOFOSSILS

The High Head Member of the Church Point Formation, Goldenville Group, in the Meguma terrane of southern Nova Scotia, contains an unusually diverse assemblage of trace fossils for being a lower Cambrian non-shallow-water succession. It is probably of Cambrian Epoch 2 age but may be late Terreneuvian. Sedimentary and stratigraphical features of the High Head Member suggest deposition by turbidity currents in a deep-water setting. Previous studies have documented the presence of Oldhamia, Treptichnus, Teichichnus, stellate trace fossils, meniscate trace fossils and various meandering trace fossils. New observations include a large specimen of Paleodictyon, similar to earlier reports of this ichnogenus from other formations of the Goldenville Group, and a specimen of Squamodictyon. In addition to its age, the High Head trace fossil assemblage is remarkable for the co-occurrence of forms that are generally interpreted as widely different ethologies, such as Oldhamia, Paleodictyon, Treptichnus and stellate traces, all found within a few decametres of stratigraphically uniform section. Another stand-out feature is the large size of the Treptichnus, Paleodictyon and stellate trace fossils. In many respects the High Head trace fossil assemblage is more similar to those first found in Ordovician deep-water settings, and it raises serious questions about the fidelity of the preserved Cambrian record of deep-water trace fossils.