Subarctic Tidal Flats in Areas of Large Tidal Range, Southern Baffin Island
Total Page：16
File Type：pdf, Size：1020Kb
Document generated on 10/01/2021 4:46 p.m. Géographie physique et Quaternaire Subarctic tidal flats in areas of large tidal range, southern Baffin Island, eastern Canada Les estrans subarctiques en zones de fort marnage, sud de l’île de Baffin, Canada Subarktische Wattenmeere in Gebieten von hohem Gezeitenausschlag, südliche Baffininsel, Ost Kanada S. B. McCann, J. E. Dale and P. B. Hale Morphologie littorale et marine Article abstract Volume 35, Number 2, 1981 Wide, boulder-strewn intertidal flats occur around the head of Frobisher Bay and along parts of the shoreline of Cumberland Sound, in southeast Baffin URI: https://id.erudit.org/iderudit/1000436ar Island. The coastal environment is characterized by large tidal ranges, severe DOI: https://doi.org/10.7202/1000436ar 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, See table of contents 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 Publisher(s) zonation across the tidal flats; tidal action and sea ice processes; and geological Les Presses de l’Université de Montréal 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 ISSN concentration of boulders in the middle tidal flat zone at Koojesse Inlet and in 0705-7199 (print) the boulder barricade at the seaward margin of the Pangnirtung flats. 1492-143X (digital) Biological observations show a zonation of intertidal flora and fauna across the intertidal zone at Koojesse Inlet. An outstanding problem concerns the mode of Explore this journal 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. Cite this article McCann, S. B., Dale, J. E. & Hale, P. B. (1981). Subarctic tidal flats in areas of large tidal range, southern Baffin Island, eastern Canada. Géographie physique et Quaternaire, 35(2), 183–204. https://doi.org/10.7202/1000436ar Tous droits réservés © Les Presses de l’Université de Montréal, 1981 This document is protected by copyright law. Use of the services of Érudit (including reproduction) is subject to its terms and conditions, which can be viewed online. https://apropos.erudit.org/en/users/policy-on-use/ This article is disseminated and preserved by Érudit. Érudit is a non-profit inter-university consortium of the Université de Montréal, Université Laval, and the Université du Québec à Montréal. Its mission is to promote and disseminate research. https://www.erudit.org/en/ Géographie physique et Quaternaire, 1981,vol . XXXV, n°2 , p. 183-204, 23 fig., 1 tabl. SUBARCTIC TIDAL FLATS INAREA S OF LARGE TIDAL RANGE, SOUTHERN BAFFIN ISLAND, EASTERN CANADA S.B. McCANN, J.E. DALE and P.B. HALE, Department of Geography, McMaster University, Hamilton, Ontario L8S 4K1 . ABSTRACT Wide, boulder-strewn in RÉSUMÉ Les estrans subarctiques en ZUSAMMENFASSUNG Subarktische Wat- tertidal flats occur around the head of zones de fort marnage, sud de l'île de tenmeere in Gebieten von hohem Gezei- Frobisher Bay and along parts of the Baffin, Canada. De vastes estran cou tenausschlag, sùdliche Baffininsel, Ost shoreline of Cumberland Sound, in verts de cailloux existent dans le secteur Kanada. Grosse, mit Felsblôcken ùber- southeast Baffin Island. The coastal en amont de la baie de Frobisher et à plu sâate, Wattenmeere findet man um die vironment is characterized by large tidal sieurs endroits le long du littoral du Frobischer Bucht und an Teilen der ranges, severe winter sea ice conditions, détroit de Cumberland, au SE de l'île de Kùstenlinie des Cumberland Sundes im and a relative sea level history which Baffin. Le milieu littoral est soumis à des Sùd-Osten der Baffininsel. Die Kùstenum- involves rapid and then decreasing land marées de forte amplitude, à des con welt ist durch hohe Gezeitenausschlâge, emergence during the earlier part of the ditions rigoureuses d'englacement et harte Winter-See -Eis -Verhâltnisse, und Holocene, succeeded by slight recent à une variation du niveau marin postgla eine dazu gehôrende Wasserstand- submergence. Summer field investiga ciaire. Des recherches ont été entre Geschichte gekennzeichnet. Im Semmer tions were carried out at two sites, prises, en été, dans deux sites : le ren wurden Beobachtungen an Ort und Koojesse Inlet on Frobisher Bay, where trant de Koojesse dans la baie de Stelle gemacht, Koojesse Inlet an der ice breakup conditions were also Frobisher où les conditions du dégla Frobischer Bucht, wo Eisaufbruch monitored, and Pangnirtung Fiord off cement ont été étudiées de près, et dans Verhâltnisse auch studiert wurden, und Cumberland Sound. The results are le fjord de Pangnirtung dans le détroit Pangirtung Fiord am Cumberland Sund. summarized under three headings: de Cumberland. Les résultats apparais Die Resultate wurden unter drei Ûber- physical and biological zonation across sent sous trois entêtes: la zonation schriften gesammelt: physische und the tidal flats; tidal action and sea ice bio-physique des estrans ; les processus biologische Gebietsaufteilung in den processes; and geological evolution of glaciels et l'action de la marée; l'évolu Wattenmeeren, Gezeiten Einfluss und the tidal flats. Comparisons are made tion géologique des estrans. Des compa See-Eis -Vorgânge, und die geologische with similar settings described by others raisons sont faites avec des milieux Entwicklung der Wattenmeere. Man in Labrador and Ungava Bay. The similaires décrits par d'autres cher macht Vergleiche mit âhnlichen Verhâl- sedimentary shores at both Baffin Island cheurs, notamment au Labrador et dans tnissen die von anderen Autoren in sites exhibit a distinct physical zonation, la baie d'Ungava. Les rivages en matériel Labrador und der Ungava Bucht be- most evident in the concentration of meuble des deux sites étudiés à Baffin schrieben wurden. Die Sediment KOsten boulders in the middle tidal flat zone at montrent une zonation distincte en ce in beiden Baffininsel Orten zeigen eine Koojesse Inlet and in the boulder bar qui a trait à la répartition des cailloux, genaue physische Gebietsaufteilung, ricade at the seaward margin of the ceux-ci étant concentrés dans la partie die sich am besten durch die Ansamm- Pangnirtung flats. Biological observa médiane de l'estran dans le rentrant lung von Felsblôcken im mittleren Wat- tions show a zonation of intertidal de Koojesse, alors qu'à Pangnirtung ils tenmeergebiet des Koojesse Inlet und in flora and fauna across the intertidal zone forment des cordons allongés parallèle der Blockbarrikade an der seewàrtigen at Koojesse Inlet. An outstanding ment à la limite des basses mers. Les Grenze des Pangnirtung Watts kenn- problem concerns the mode of transport levés biologiques ont permis de faire une zeichnet. Biologische Observationen of very large boulders. Pushing and zonation de la flore et de la faune de l'es zeigen eine Gebietsaufteilung der rolling, by ice floes which are confined tran du rentrant de Koojesse. Un des Gezeiten Flora und Fauna im Watten- to the intertidal zone by the solid ice in problèmes majeurs soulevés concerne meer am Koojesse Inlet. Ein besonderes the offshore zone during the critical le mode de déplacement des méga Problem bildet die Frage des Trans early phase of breakup may be more blocs. Il semble que les pressions laté portes von sehr grossen Felsblôcken. appropriate processes than ice rafting. rales exercées sur les blocs par les Stossen und Rollen durch Eisschollen radeaux de glace, lors du déglacement, die auf den Gezeitensaum durch die soient plus efficaces que la prise en teste Eisdecke ausserhalb der Kùsten charge suivie d'une dérive et d'un dé linie, in der wichtigen frùhen Eisauf- lestage des blocs, au hasard de la fonte, bruchszeit veschrânkt sind, erscheinen à divers niveaux de la zone intertidale. als mehr angepasste Vorgânge als Eis- flôssen. 184 S.B. McCANN, J.E. DALE and P.B. HALE INTRODUCTION may be expressed physically, in variations in sediment size and sedimentary structures across the profile, or Tidal effects play a significant role in determining biologically, in different associations of plants and sedimentation patterns and sedimentary sequences in animals at the various tidal levels. Chemical and bio a variety of subtidal and intertidal settings, including chemical aspects of tidal sedimentation may also be open beaches, inlets, deltas, estuaries and across the manifest in this way (HARDIE, 1975). A fining-landwards shallow continental shelf. The interplay of wave pro sedimentological zonation is documented in many mid- cesses and river processes with tidal effects has pro latitude clastic tidal flat situations (GROEN, 1967; vided a central theme in various attempts to classify and POSTMA, 1961; VAN STRAATEN and KUENEN, 1958), explain the morphology and sedimentology of these where muds are transported towards shore and de coastal sedimentary environments. This paper examines posited in the upper part of the intertidal profile. the subarctic tidal flat environment, where the presence of sea-ice adds another variable of considerable im The central question posed at the outset of our portance. research concerned the extent to which 'normal' sedi mentary processes due to tides, and the resulting mor The main objective here is to present a preliminary phological, sedimentological and biological patterns, analysis of the wide bouldery tidal flats developed in the are modified or suppressed by sea-ice action in sub embayments and fiords of southeast Baffin Island, arctic tidal flat environments. ELLIS and WILCE (1961) where tidal ranges are large and sea-ice dominates the have documented a biological zonation, indicating that coastal regime.