Banks Island Research Articles

Paleomagnetism of Quaternary and late Tertiary sediments on Mokowan Butte, southwestern Alberta

Mokowan Butte in southwestern Alberta is capped by 32 m of unconsolidated sediment comprising five tills and their associated paleosols. Previous stratigraphic work has indicated that the older tills are probably Early Pleistocene to late Tertiary in age. Paleomagnetic studies, based on 125 samples, show that the uppermost till–paleosol unit and the modern subsoil are normally magnetized, whereas the till–paleosol units from the middle of the sequence have reversed magnetization. We argue that these belong to the Brunhes and Matuyama polarity zones, respectively. The lowest part of the sequence has not been studied in detail and is generally too coarse for paleomagnetic sampling, and samples that have been obtained contain no accurate record of the paleofield. These new data, together with those from Wellsch Valley in Saskatchewan, Banks Island in the Northwest Territories, Fort Selkirk in the Yukon, and Merritt in British Columbia, bring to five the number of early Quaternary sequences in Canada that have yielded a record of glacial sediments deposited during the Matuyama chron, and hence record glacial events prior to the last reversal of the geomagnetic field (720 ka).

YERSINIOSIS IN FREE-RANGING MUSKOXEN ON BANKS ISLAND, NORTHWEST TERRITORIES, CANADA

Sixty-seven muskox (Ovibos moschatus) carcasses, 53 skeletal remains and two sick muskoxen were seen during an aerial survey of the Thomsen River region, northern Banks Island, Northwest Territories, Canada in late July 1986. Complete necropsies were performed on 29 muskoxen estimated to have died within the previous 3 to 5 days. Twenty were diagnosed with acute yersiniosis due to Yersinia pseudotuberculosis serotype 1B and were in excellent body condition. A diagnosis could not be made on seven animals due to marked autolysis; however, these muskoxen also were in excellent body condition. The remaining two were aged, emaciated muskoxen. This report describes the first occurrence of yersiniosis in free-ranging muskoxen and the first documentation of large scale mortality due to this disease in a free-ranging population of wild ungulates.

Interaction of internal waves with the seabed on continental shelves

Large-amplitude internal waves generated by tidal fluctuations at the outer edge of the continental shelf propagate shoreward and interact with seabed sediment. A crude mathematical model describing the propagation of such internal waves is used to predict wave-induced sediment flux and thereby to provide a possible explanation of sand-ridge formation on continental shelves. The ocean over the shelf is modelled as a two-layer system and it is assumed that the internal waves are generated at the shelf edge. Field measurements indicate that the very low frequency tidal fluctuations create a train of internal oscillations of periods between 15 and 20 min. Because of nonlinear effects these wave trains generate differential sediment fluxes and, in the model, this leads to the creation of seabed topography. The predictions of the model are tested against field data collected on the eastern Canadian continental shelf and in particular on Sable Island Bank and the Grand Banks of Newfoundland. The comparisons between predictions and measurements are encouraging especially in light of the fact that the model has no free parameters.

Sediment transport on the eastern Canadian continental shelf

A synthesis is presented of the sediment transport pathways resulting from hydrodynamic processes over the eastern Canadian continental shelf. This is based on interpretation of bedform type and orientation, grain size trends, sediment stratigraphy, visual observation and direct measurements. These pathways are then compared with results of numerical simulations of the transport of 0.35 mm (medium) sand for the Grand Banks of Newfoundland, the Scotian Shelf and the Gulf of Maine. The abundance of hydrodynamically reworked sediment increases from north to south. There is no evidence for sediment transport on the Baffin Shelf or Arctic Island Channels due largely to ice cover and deep (200 m) water. Sediment transport on the Labrador Shelf, by contrast, is apparent though restricted to bank tops in depths less than 120 m. This transport is predominantly to the southeast under the influence of strong wind-driven and geostrophic flows. The Grand Banks of Newfoundland is subject to storm-induced sand transport in depths less than 120 m. Transport here is to the south and southeast over much of Grand Bank and Avalon Channel. Above approximately 60 m the seabed is devoid of sand, suggesting scouring; between 60 and 120 m sand transport takes place principally as bedload. The shelf immediately south of Newfoundland is subject to strong easterly sediment transport that has scoured the banktops of all but gravel-sized sediment. The Scotian Shelf and Georges Bank also exhibit storm-induced sediment transport that is tidally-modulated in depths less than 100 m. The predicted and observed sand transport pathways are remarkably consistent. Predicted zones of sand convergence and divergence correspond to known regions of sand accumulation and depletion, respectively. Quantitative predictions are, by contrast, only within an order of magnitude of observations. Percentage exceedence predictions of sand transport for the Hibernia (Grand Banks of Newfoundland) and Venture (Sable Island Bank) discovery sites show strongly linear trends on a Gumbel distribution. These plots show that intense storms (greater than 20 year return interval) dominate net transport at Hibernia, whereas short-term storms (annual or shorter return interval) dominate at Venture.

Observations of aeolian transport and niveo‐aeolian deposition at three lowland sites, Canadian arctic archipelago

AbstractObservations of wind action were made in the late winter, spring and summer at three lowland sites located on Banks Island (1977‐79), Melville Island (1986‐87) and Ellesmere Island (1989‐90). Erosion pin measurements in north‐central Banks Island showed minimal activity on interfluves and the highest rates at a blowout site in an unvegetated sand plain. The timing of aeolian activity during the year depended on the site characteristics. Where the snow cover was incomplete in winter, either because a rugged microtopography resulted in terrain elements protruding above the surface of the snow or because sublimation of snow exposed the ground surface, aeolian transport could occur year‐round. In areas with a flatter microtopography, summer transport took place but deflation was negligible over the winter and niveo‐aeolian deposition was confined to the autumn and spring when the snow cover was patchy. Windblown sediment became spatially concentrated by denivation at some sites and was deposited on slopes as fans or layers up to 8 cm thick. In the years this occurred, the rate of deposition was greater than sediment removal by wash or other processes and, at least in the short term, the form of the slope was changed.

Erythrocyte micronuclei in winter flounder (Pseudopleuronectes americanus): Results of field surveys during 1980?1988 from Virginia to Nova Scotia and in Long Island Sound

Erythrocyte micronuclei (MN) frequencies of 280 winter flounder (Pseudopleuronectes americanus) from Chesapeake Bay to the southern Scotian Shelf including Long Island Sound were measured. The MN data were combined with data previously reported for 224 flounder and the combined data sets were analyzed. Incidences of MN were elevated sixfold in flounder from the New York Bight Apex as compared to frequencies for fish from the inshore Gulf of Maine and Block Island Sound, and twice those found in Georges Bank and Long Island Sound flounder. Inshore New Jersey fish had higher MN frequencies than those from inshore Gulf Of Maine and Block Island Sound. The occurrence of MN in flounder from inshore Virginia was higher than in flounder from inshore Gulf of Maine and Block Island Sound. The large subset of stations from Long Island Sound indicated higher frequencies of MN in flounder from Hempstead and Shoreham as compared to most other sites in the Sound. There was no significant difference in the frequency of MN between males and females, but males had significantly more MN than sexually immature flounder. Flounder over the entire sampling area had increased levels of MN during the fall months of the year. This is probably influenced by the maternal cycle of gonadal maturation.

The History, Status and Management of Muskoxen on Banks Island

Historical and archaeological records suggest that muskoxen (Ovibos moschatus) were once abundant on Banks Island. They declined around the turn of the 20th century and remained at very low population levels until the 1970s. The causes of the scarcity of muskoxen are unknown, but severe freezing rains and subsequent forage unavailability likely played a role. Aerial surveys documented an increase in the estimated population size from 3800 in 1972 to 34,225 in 1989. The rapid increase in muskox numbers has been a source of concern to the local users, who view the muskoxen as detrimental to the caribou (Rangifer tarandus pearyi), which have declined in number. Since the mid-1980s, productivity of 3-year-old muskox cows and calf survival have decreased and the prevalence of parasites has increased. Our data do not allow us to distinguish between whether those changes are density-dependent population responses or the effects of the severity of winter weather. Current management focuses on monitoring the trend of population size, the condition and reproduction of the muskoxen.Key words: muskoxen, Ovibos moschatus, Banks Island, numbers, harvest, weather, population regulation

Detection and Classification of Muskox Habitat on Banks Island, Northwest Territories, Canada, Using Landsat Thematic Mapper Data

The feasibility of using Landsat Thematic Mapper data for mapping muskox summer habitat was tested on northern Banks Island, Northwest Territories. Digital image enhancement and classification techniques were examined to determine if summer foraging habitats could be detected and mapped using Thematic Mapper imagery. Interpretations of the satellite data were verified in the field during the summers of 1988 and 1989. The most important summer foraging habitats for muskoxen included the wet sedge meadow, graminoid tundra and graminoid/dwarf shrub tundra cover types. These lowland habitats were generally distinguishable on enhanced colour images and were easily differentiated from upland areas. The most suitable colour composite for differentiating muskox summer habitats was the near-infrared (band 4), shortwave infrared (band 5) and red (band 3) spectral bands displayed in red, green and blue respectively. Upland cover types, including dwarf shrub tundra, hummocky tundra and dwarf shrub/lichen barrens, were more difficult to differentiate because of spectral variability resulting from differences in plant cover and site characteristics. The classified image had an overall accuracy of 88%. The summer habitats of particular importance to muskoxen had classification accuracies of 84-89%. Detection of important foraging habitats on Thematic Mapper imagery is attributable to the spectral distinctiveness of wet graminoid communities and the high spectral sensitivity and spatial resolution of the infrared sensors, which allow detection of differences in surface moisture and vegetation physiognomy.Key words: bison habitat, boreal forest, digital image analysis, supervised classification, Landsat Thematic Mapper data, habitat mapping, Bison bison athubuscue, remote sensing

Disasters and Development in Historical Context: Tropical Cyclone Response in the Banks Islands, Northern Vanuatu

The Banks Islands in northern Vanuatu are prone to tropical cyclones. While a thriving population appears to have coped with these events prior to European contact, since then a smaller population has struggled to maintain its food security following tropical cyclone events. A number of social, economic, political and resource management changes have led to a set of disaster pre-conditions which result in dependence on external food relief following tropical cyclones. Most of these changes have taken place in the intervening years between disasters and have occurred independent of the tropical cyclone hazard. However, one set of changes, the provision of food relief itself, has provided the catalyst for the other changes to occur.

The Quaternary stratigraphy of southwest Sable Island Bank, eastern Canada

Three boreholes, ten vibrocores, and high-resolution seismic reflection records were analyzed to reconstruct the stratigraphy of the topmost 50 m of the sedimentary column of southwest Sable Island Bank. The sequence is complex owing to the effects of two low stands of sea level, two periods of ice influence, and two periods of open water during the past 40,000 yr. A low stand at -98 m occurred at 28,000 to 32,000 yr B.P.; a second low stand occurred at -110 m between 13,000 and 15,000 yr B.P. Ice covered the region prior to 32,000 yr B.P. and from 11,000 to 10,000 yr B.P. Open water prevailed at other times. The sequence of sediments follows the formational subdivision of King and the member subdivision of Amos and Knoll. The Sable Island Sand and Gravel Formation is subdivided into three members: trough-bedded sand, cross-bedded sand, and conformably bedded sand. The conformably bedded sand formed under heavy sea ice and represents the Younger Dryas event. The uppermost two members result from shelf sediment reworking. The Emerald Silt Formation is subdivided into four members: channel gravel, upper stratified sand/fines, barren gravelly/sand, and lower stratified sand/fines and two regional discontinuities, R1 and R2. The coarser-grained facies of the channel gravel and barren gravelly/sand members are the result of reworking during late and mid-Wisconsinan transgressions of Sable Island Bank. The upper stratified sand/fines member is interpreted as an open-water marine deposit formed during the Scotian Stade. The lower stratified sand/fines member is interpreted as a glacio-marine deposit formed during the Digby Stade.

The origin and stability of sand ridges on Sable Island Bank, Scotian Shelf

Two models are used to predict the evolution of sand ridges on Sable Island Bank: the wave model of Boczar-Karakiewicz and Bona (1986a) and the sediment transport system: SED1DG ( Davidson and Amos, 1985) . The genesis of sand ridges is proposed to be the result of differential potential sediment transport ( i d) induced by 50–80 s period infragravity waves. Sand ridge crests are found where the spatial horizontal derivative of the transport rate ( i d) is negative, and troughs develop where this derivative is positive. These crests and troughs are orthogonal to the propagation direction of the infragravity waves, their consecutive distances vary in repetition length ( L r) in proportion with depth, and near the shelf break they are phase-locked to the shelf edge. Refraction of infragravity waves on Sable Island Bank is minor compared to refraction at the shelf edge. Sand ridge orientation is, therefore, largely determined by the orientation of the shelf edge over which the infragravity waves pass. The time scale for sand ridge generation, the degree of ridge asymmetry and the rate of migration are proposed to be the direct result of the rate and direction of shelf sediment transport which, for Sable Island Bank, is storm controlled and almost independent of the infragravity wave field. We predict that a typical time-scale for ridge formation in 40 m of water is 890 years with a time-averaged migration rate of 1.9 m y −1.

Optimal Body Size in Lesser Antillean Anolis Lizards‐‐A Mechanistic Approach

For the past twenty years, it has been recognized that body size is convergent among solitary species of Anolis lizards endemic to different island banks of the Lesser Antilles. Community ecologists have assumed that this "solitary size" is an optimal size, yet the basis behind such optimality has not been shown. Our goal in this study was to explore the existence of an energetic basis of an optimal body size in these lizards. A computer model is presented that incorporates quantitative descriptions of lizard metabolism, locomotion, digestion, and visual acuity, and simulates foraging in a sit—and—wait predator. Quantitative estimates of daily foraging energetics are presented, which are then used together with estimates of resting metabolism to simulate growth. An optimal growth strategy is incorporated to determine adult body sizes that maximize lifetime reproductive output. Such optimal body sizes were determined for different prey densities and activity levels, predator life expectancies, and field metabolic rates. Predicted optimal body sizes are close to the observed body sizes of Lesser Antillean anoles, and are relatively insensitive to both levels of prey activity and up to fourfold differences in prey density, while life expectancy and rates of field metabolism may influence predictions. The insensitivity of predicted optimal body size to prey density lends support to the assumption that the solitary size observed among anoles throughout the Lesser Antilles is an optimal body size. Additional findings were made regarding home—range sizes, growth patterns, and visual constraints to foraging performance.

Proterozoic deformation beneath Banks Island: implications for the regional extent of the Racklan orogeny

Seismic reflection data from the northeast corner of Banks Island in arctic Canada show that Proterozoic layers were subjected to at least two deformational events prior to the Cambrian. The oldest of these events involved folding and faulting(?) from west-northwest to east-southeast. The ages of the layers that were subjected to this deformation are unknown; however, younger Proterozoic layers, probably correlative with the Shaler Group (ca. 1.1–0.8 Ga), unconformably overlie the folded and faulted layers, and were themselves regionally arched prior to the Cambrian. The relative position of the oldest deformed strata is thus the same as that of the strata observed to the south beneath the Anderson Plains, where thrust faulting and folding deformed pre-Mackenzie Mountains Supergroup (Shaler Group equivalent) layers during at the time of the Racklan orogeny (ca. 1.1–1.2 Ga). Distant effects of the Racklan orogeny may therefore extend to at least the northeast side of Banks Island.

The diary of Assistant Surgeon Henry Piers, HMS Investigator, 1850–54

From the 16th to the mid 19th century, many voyages were made from England to discover a North West Passage between the Atlantic and the Pacific oceans. The Investigator was one of some 40 vessels that searched for the lost North West Passage expedition of 1845-48 under the command of Sir John Franklin in HM Ships Erebus and Terror, which became beset among what are now known as the Canadian Arctic Islands. The "Investigators" found no trace of Franklin, but were the first to traverse the North West Passage, although their ship had to be abandoned in Mercy Bay on Banks Island after two winters there. The diary of Assistant Surgeon Henry Piers, from the manuscript collection of the National Maritime Museum, Greenwich, is here examined. Reference is also made to the narrative and report published by the senior surgeon of the Investigator, Dr Alexander Armstrong.

Late Tertiary and Early Pleistocene Deposits and History of Banks Island, Southwestern Canadian Arctic Archipelago

Fossil-rich sediments on Banks Island provide an excellent record of events and conditions that prevailed in arctic Canada during the late Tertiary and Early Pleistocene. In the late Tertiary, fluvial sands and gravels of the Beaufort Formation and related deposits were laid down on the coastal plain facing the Beaufort Sea. Relative sea level was lower than today. Both mixed deciduous/coniferous and coniferous forests existed on Banks Island. Mean July temperatures must have been +10 degrees C warmer than present. The Early Pleistocene Worth Point Formation records a period during which preglacial landscapes were modified by fluvial, eolian, and colluvial processes. Continuous permafrost was likely present, sea level was lower than today, and southern Banks Island was covered by an open larch-dominated forest-tundra. Mean July temperatures were probably some 5-7 degrees C warmer than present. Although some evidence indicates possible earlier glaciations, the best record of an early continental ice advance is provided by widespread glacial and marine sediments of the Duck Hawk Bluffs Formation laid down during the Early Pleistocene Banks Glaciation. This advance was distinctly more extensive than Middle or Late Pleistocene ones and glacio-isostacically controlled sea levels were much higher than those of today. During the Early to Middle Pleistocene Morgan Bluffs Interglaciation, climate on Banks Island was cooler than in preglacial times. Although the tree line may have extended to the southern part of the island, fossil remains in seven localities indicate typical low arctic conditions (mean July temperatures 2-5 degrees C warmer than present). Eustatic sea level was some 30 m higher than the present and permafrost was continuous. The Banks Island record provides critical information on periods when conditions in the Arctic were significantly warmer than today. As such it can serve as a basis to understand and forecast the nature and impact of future man-induced atmospheric warming.

Late Cenozoic paleomagnetic record of Duck Hawk Bluffs, Banks Island, Canadian Arctic Archipelago

Detailed paleomagnetic investigations have been completed on unconsolidated sediments from Duck Hawk Bluffs on Banks Island, in the Canadian Arctic Archipelago, that record some of the oldest late Cenozoic glacial and nonglacial events in Canada. The preglacial Worth Point Formation, the overlying Duck Hawk Bluffs Formation, including marine and glacial deposits laid down during the Banks Glaciation, and the lower part of the interglacial Morgan Bluffs Formation have magnetically reversed directions and therefore are of Matuyama age (>790 ka). Upper Morgan Bluffs Formation organic beds and deposits of the younger Thomsen Glaciation, Cape Collinson Interglaciation, and Amundsen Glaciation are normally magnetized and therefore of Brunhes age (<790 ka). The Brunhes–Matuyama boundary is recorded in the upper portion of the Morgan Bluffs Formation. Its precise position within the interglacial sequence can be identified, since the sediments document the gradual change from reversely inclined directions to normally inclined ones. These results confirm that the preglacial Worth Point Formation is at least Early Pleistocene in age and that the Banks Glaciation (the oldest and strongest continental glaciation recorded in the western Arctic) and a good part of the Morgan Bluffs Formation are of Early Pleistocene age. The study also documents a rare site in Canada where terrestrial sediments record the Brunhes–Matuyama transition and in doing so permits a precise correlation of part of the Banks Island stratigraphy with other key late Tertiary and Early to Middle Pleistocene arctic terrestrial and marine sequences.

Late Tertiary Plant Macrofossilsf from Localities in Arctic/Subarctic North America: A Review of the Data

Bryophyte and vascular plant fossils occur at many late Tertiary sites in Alaska and northern Canada. A number of these floras are received here. The oldest flora, possibly of late Early Miocene age, is probably the one from the Mary Sachs gravel at Duck Hawk Bluffs, Banks Island. The youngest are of early Quaternary age. The floras are of several types. The youngest (Cape Deceit Formation) contains only plants that grow in the Arctic and Subarctic today. The Meighen Island Beaufort Formation contains a few extinct taxa (Aracites globosa) and fossil plants, such as Sambucus, Comptonia, and Physocarpus, that are not found in the present subarctic and arctic regions of North America. Some of these floras also contain fossils of a five-needle pine that may represent the Japanese Stone pine (Pinus pumila). A third group of floras, from Cone Bluff and Lava Camp, Alaska, usually contains more extinct plants (Epipremnum crassum, Decodon and cf. Paliurus) as well as fossils of pines in the subsection Cembrae. The Mary Sachs gravel flora, with taxa such as Metasequoia, Glyptostrobus, Taxodium, Juglans, and Liriodendron, stands apart from all three of the above-mentioned floral types. The Mary Sachs gravel flora represents mixed coniferous and hardwood forests. Most of the other floras represent coniferous forests that were floristically richer than present boreal forest. Some of the richness is due to taxa now found only in Eurasia. The Meighen Island Beaufort flora and some of those from the high-level alluvium on Ellesmere Island represent forest tundra. Several lines of evidence show that the Beaufort Formation on Meighen Island in the Canadian Arctic is about 3 million years old. Several of the younger floras contain abundant, well-preserved bryophyte fossils. Unlike the vascular plants, all of them represent extant species.

Beaufort Formation (Late Tertiary) as Seen form Prince Patrick Island, Arctic Canada

The Beaufort Formation, in its type area on Prince Patrick Island, is a single lithostratigraphic unit, a few tens of metres thick, consisting of unlithified sandy deposits of braided rivers. Organic beds in the sand have yielded more than 200 species of plants and insects and probably originated during the Pliocene, when the area supported coniferous forest. This Beaufort unit forms the thin eastern edge of a northwest-thickening wedge of sand and gravel beneath the western part of the island. These largely unexposed beds, up to several hundred metres thick, include the Beaufort unit and perhaps other older or younger deposits. On the islands northeast and southwest of Prince Patrick Island (Meighen Island to Banks Island), the name Beaufort Formation has been applied to similar deposits of late Tertiary age. Most recorded Beaufort beds on these islands are stratigraphically and paleontologically equivalent to the "type" Beaufort, but a few sites that have been called Beaufort (such as Duck Hawk Bluffs and the lower unit at Ballast Brook, on Banks Island) differ stratigraphically and paleontologically from the "type" Beaufort. This paper recommends that these deposits (probably middle Miocene) and others like them be assigned new stratigraphic names and not be included in the Beaufort Formation as now defined. Informal names Mary Sachs gravel (Duck Hawk Bluffs) and Ballast Brook beds are proposed as an initial step. Formal use of the name Beaufort Formation should be restricted to the western Arctic Islands.

Observations on buried glacier ice and massive segregated ice, western arctic coast, Canada

AbstractThe two main theories for the origin of the thick bodies of massive ground ice known to exist in the Western Canadian Arctic are (1) segregation‐injection and (2) buried glacier ice. Because buried glacier ice may contain significant quantities of stratified debris and may have experienced thawing and refreezing (regelation) on several occasions, it may be very difficult to distinguish between massive segregated ice and buried basal glacier ice. By use of cryostratigraphic and cryotextural (petrofabric) observations, massive ground ice bodies observed in the Sandhills Moraine, southern Banks Island, and the southern Eskimo Lakes region, Pleistocene Mackenzie Delta, are both interpreted as basal glacier ice. Other massive ground ice bodies which have been examined in the Western Canadian Arctic are best explained in terms of segregation‐injection.

Th–U disequilibrium dating of Middle and Late Pleistocene wood and shells from Banks and Victoria islands, Arctic Canada

An attempt has been made at dating Middle and Late Pleistocene deposits from Banks and Victoria islands using the Th–U disequilibrium method. Geological correlations are difficult to establish because of the discontinuous nature of the terrestrial units and the relative absence of datable fossil wood and shells. The Th–U geochemical system likely remained closed for extended periods because of the presence of permafrost, which implies very limited or absent water circulation. The Th–U age determinations obtained confirmed the previously established stratigraphic framework and provide chronological information in that samples of Sangamonian age are differentiated from those that are younger (Wisconsinan and Holocene) or older (Middle Pleistocene). The Th–U disequilibrium method carefully used in areas where water circulation is limited can thus provide chronological control for sediments older than those that can be dated by the radiocarbon method.