ICHNOLOGY OF THE LOWER TRIASSIC BLIND FIORD & BJORNE FORMATIONS, SVERDRUP BASIN, ARCTIC CANADA
Latest Permian successions in the Sverdrup basin are dominated by proximal offshore through lower shoreface successions containing a moderately diverse suite of traces including Asterosoma, Phycosiphon, Scalarituba, Skolithos, Thalassinoides & exceptionally large Zoophycos.
Early Triassic proximal offshore & offshore transition successions, preserved in basin center settings, contain few trace fossils. Those that do occur are small, horizontal feeding traces (Planolites & Helminthopsis). Exceptions occur within event beds transported from shallower settings including (Asteriacites & Kouphichnium). Early Triassic lower shoreface successions contain moderately diverse assemblages that include Arenicolites, Cruziana, Cylindrichnus, Diplocraterion, Lockeia, Palaeophycus, Siphonichnus, Thalassinoides & Spongeliomorpha. Although trace fossils were not observed in upper shoreface successions, intertidal flats contain a variety of trace fossils, particularly those constructed by molluscs (Beaconichnus, Gyrochorte, Lockeia, Neonerites & Protovirgularia).
Early Triassic fluvially-dominated successions include Cochlichnus, Fuersichnus, Lockeia, Skolithos, rare tetrapod footprints & a wide range of insect brooding traces. Comparison of these trace fossil assemblages with those from similar environmental settings in coeval western & northern Canadian successions suggests that environmental constraints limited infaunal diversity primarily distal of the lower shoreface.