Subarctic tidal flats in areas of large tidal range, southern Baffin Island, eastern Canada

Abstract

<jats:p>Wide, boulder-strewn intertidal flats occur around the head of Frobisher Bay and along parts of the shoreline of Cumberland Sound, in southeast Baffin Island. The coastal environment is characterized by large tidal ranges, severe winter sea ice conditions, and a relative sea level history which involves rapid and then decreasing land emergence during the earlier part of the Holocene, succeeded by slight recent submergence. Summer field investigations were carried out at two sites, Koojesse Inlet on Frobisher Bay, where ice breakup conditions were also monitored, and Pangnirtung Fiord off Cumberland Sound. The results are summarized under three headings: physical and biological zonation across the tidal flats; tidal action and sea ice processes; and geological evolution of the tidal flats. Comparisons are made with similar settings described by others in Labrador and Ungava Bay. The sedimentary shores at both Baffin Island sites exhibit a distinct physical zonation, most evident in the concentration of boulders in the middle tidal flat zone at Koojesse Inlet and in the boulder barricade at the seaward margin of the Pangnirtung flats. Biological observations show a zonation of intertidal flora and fauna across the intertidal zone at Koojesse Inlet. An outstanding problem concerns the mode of transport of very large boulders. Pushing and rolling, by ice floes which are confined to the intertidal zone by the solid ice in the offshore zone during the critical early phase of breakup may be more appropriate processes than ice rafting.</jats:p>

Anadromous char as an alternate food choice to marine animals: A synthesis of Hg concentrations, population features and other influencing factors

“…Char provided were among the youngest investigated in our study and were small, possibly as a consequence of fishing pressures. Carbon isotope values suggested a greater reliance on marine benthic algae than at sites in the western Arctic; the tidal range at Pangnirtung is large reaching 6 m and exposing extensive boulder-strewn intertidal flats (McCann et al, 1981); kelp beds are abundant. Hg concentrations were moderately low (annual mean 0.07 ± 0.03 μg/g) and were previously measured on two occasions in the early 1990s.…”

Stratigraphic signature of the late Palaeozoic Ice Age in the Parmeener Supergroup of Tasmania, SE Australia, and inter-regional comparisons

“…Similar cyclicity was noted by Fielding et al (2008b) from the Lower Permian lower Pebbley Beach Formation of the southern Sydney Basin. Facies B1 to B3 also bear some similarity to Pleistocene glacimarine deposits of the Yakataga Formation in southern Alaska (James et al, 2009a), and to boulder barricades and coarse-grained material transported by sea ice (Rosen, 1979;McCann et al, 1981;Gilbert, 1990).…”

“…Each bed could record a single glacial cycle, or perhaps more likely the large-scale release of icebergs during the deglacial phase of such cycles (cf. Eyles et al, 1997;Fielding et al, 2008b;Rygel et al, 2008), or the result of sea ice rafting of debris away from a high relief shoreline such as that associated with paleo-Maria Island during the Permian (e.g., Rosen, 1979;Dionne, 1981;McCann et al, 1981;Banks & Clarke, 1987).…”

Exposure to Coastal Hazards in a Rapidly Expanding Northern Urban Centre, Iqaluit, Nunavut

“…The rate of downcutting on the tidal flats is unclear. Sediment movement is dominated by sea ice dynamics (McCann et al, 1981;McCann and Dale, 1986;Leech, 1998;Dale et al, 2002). Ice prevails for an average of nine months of the year.…”