East-central Ellesmere Island Research Articles

Holocene fluctuations of Leffert Glacier and nearby outlet glaciers, Ellesmere Island, Nunavut, Canada

ABSTRACTRadiocarbon age determinations on marine shells in lateral moraines and other deposits several kms behind the present day termini of tidewater outlet glaciers from the Prince of Wales Icefield, east-central Ellesmere Island, Nunavut, Arctic Canada, as well as tidewater glaciers from two nearby ice-caps, show that these glaciers have fluctuated considerably through the Holocene, both in length and in thickness. The terminus of Leffert Glacier, for which the best documentation is available, has been more than 20 km west of the position that it occupied in 1898–1899, when it was mapped for the first time. Leffert Glacier was much reduced in size for a period of several thousand years, between roughly 6450 and 185014C years BP. Other major outlet glaciers that have experienced significant fluctuations of their termini during the Holocene are: 1) MacMillan, Ekblaw and Tanquary glaciers in the Baird Inlet area, 2) Stygge Glacier and adjacent unnamed glaciers at the head of Jokel Fiord, 3) Benedict Glacier at the head of Sawyer Bay and 4) Parrish Glacier, the southernmost outlet glacier from the Agassiz Ice Cap. Of the glaciers investigated, only Alfred Newton Glacier, south of Cape Herschel, has surged during the period of field observation (1977 to 2009), and this glacier is now receding from the position attained in a surge which commenced in 1981. The terminus of Ekblaw Glacier, at the head of Baird Inlet, is now well forward of the position it occupied in 1950, when the first aerial photograph coverage was achieved.

Diatom-inferred Holocene climatic and environmental changes in an unusually subsaline high Arctic nunatak pond on Ellesmere Island (Nunavut, Canada)

Stygge Nunatak Pond is a small, shallow, closed-basin pond situated on a nunatak in Stygge Glacier at the head of Jokel Fiord, east-central Ellesmere Island, Nunavut, Canada. Its ionic concentration is unusually high by inland Arctic standards, with specific conductivity measured at up to 1,090 μS/cm, making this site a rare example of a subsaline athalassic Arctic pond. Small, closed-basin lakes and ponds are particularly sensitive to changes in the balance between precipitation and evaporation (P–E), which affect the site’s chemical, physical and biological characteristics. Such lakes and ponds therefore have the potential to serve as sensitive archives of past environmental change, which can be reconstructed using paleolimnological techniques. Diatom assemblages from two sediment cores (a short gravity core [21.5 cm] and a long core of frozen material [387 cm]) were examined so as to reconstruct regional environmental changes. Basal radiocarbon dating of the long core suggests that the pond has existed since before 10,500 cal. year BP. The diatom assemblages from both cores record similar ecological changes since approximately 2,200 cal. year BP, with a stable, coldwater assemblage dominated by Fragilaria construens var. venter. This assemblage was replaced in the early- to mid-20th century by dramatic, unprecedented expansion in periphytic taxa with more complex life forms, especially Cymbella descripta, Navicula halophila and Achnanthes minutissima. These assemblage shifts are indicative of recent warming, with a longer open-water period, expanded littoral substrates, and increased ionic concentration, as would be expected with enhanced evaporation relative to precipitation. Between ~10,500 and ~6,200 cal. year BP, the diatom assemblages underwent a shift from a near monoculture of F. construens var. venter to a more complex, epiphytic assemblage, which then reverted back to the former virtual monoculture. These shifts may provide further evidence for an early Holocene thermal maximum in this region of the Arctic, followed by Neoglacial cooling. However, interpretation of assemblages before ~6,200 cal. year BP is complicated by the fact that the sediment beneath 47 cm depth is unconsolidated and embedded within a core of solid ice, a feature that has not been reported in any other Arctic paleolimnological study to date. Superficial examination of the contact surfaces of the ice, and the fact that radiocarbon ages obtained from entrained sediment are chronologically consistent with those from the sediment above, suggest that the ice might be intrasedimental segregation ice.

Breeding Bird Surveys at Alexandra Fiord, Ellesmere Island, Nunavut (1980–2008)

Long-term monitoring of bird populations in the Arctic is of considerable interest as this area is experiencing rapid climate warming; however, multi-decadal studies in the Canadian High Arctic are rare. Over five summers between 1980 and 2008, we conducted breeding bird surveys by walking transects and mapping territories in a periglacial lowland on east-central Ellesmere Island, Nunavut. In all survey years, snow bunting (Plectrophenax nivalis), Lapland longspur (Calcarius lapponicus), and Baird's sandpiper (Calidris bairdii) were the most abundant species. Over the study period, the assemblage of breeding bird species appears to have changed little, except for an increase in Lapland longspur. In the summer of 2008, we also compared two techniques for censusing territories. We found that spot-mapping, a simple and cost-effective method, produced similar results to the more labour-intensive active-flushing. Spot-mapping is therefore suitable for conducting bird surveys in northern locations where the vegetation is short, the terrain is flat, and the visibility is extensive. In the coming years, it will be important to continue monitoring Arctic birds to determine how climate change is affecting their breeding populations.

Tracking Long-Term Environmental Changes in Arctic Lakes and Ponds: A Paleolimnological Perspective

Rock Basin Lake, Baird Inlet (east-central Ellesmere Island, Nunavut, Canadian High Arctic) was the site of the first detailed paleolimnological study from the circumpolar region, which used diatom and chrysophyte microfossils to track past climatic change. Photo: John P. Smol, August 1987. H IGH-LATITUDE REGIONS have repeatedly been identified as important reference areas for environmental change research, as they are especially sensitive to even small climatic changes and are often the first to show signs of environmental shifts. Moreover, climatic changes occurring at high latitudes have profound effects on other regions. Unfortunately, long-term monitoring data are generally lacking for most regions, and this is especially true for the Arctic. Without these data, it is difficult to determine whether environmental conditions are changing, and if so, to specify the magnitude and direction of change. Fortunately, a variety of natural archives of environmental change (e.g., ice cores) can be used to reconstruct these missing data sets. One rapidly emerging area of research in the Arctic is paleolimnology, which is the science of reconstructing past lake and pond histories from the proxy data contained in sediment profiles (Smol, 2002). As lakes represent a common feature of most Arctic regions, paleolimnological techniques have now been applied to a wide variety of research questions (Pienitz et al., 2004). Dated sediment cores typically archive a very rich history of past limnological conditions, based on indicators such as fossil algae (especially diatoms and chrysophytes) and invertebrates (such as Cladocera and aquatic insect remains), as well as a suite of physical and chemical indicators, such as metals and contaminants (Smol, 2002). My Arctic limnology and paleolimnology research program began in 1983, when Dr. Weston Blake Jr., now an emeritus scientist at the Geological Survey of Canada, invited me to join his field crew at Cape Herschel on eastern Ellesmere Island. I published an early paper (part of my PhD dissertation) arguing that fluctuating lake-ice conditions (which are closely related to climatic variables) exerted a strong control on lake biota, and hence on the bioindicators preserved in lake sediments. The 1983 field season was the start of a lifelong interest in the limnology and paleoecology of Arctic lakes. In September 1984, I was hired as an assistant professor at Queen’s University, where Marianne Douglas, now a professor in the Department of Geology at the University of Toronto and holder of a Tier 1 Canada Research Chair in Global Change, was among my first cohort of students. We have been collaborating on polar research ever since. For over 20 years, we have been using both limnological and paleolimnological techniques to track a variety of environmental trends throughout the Arctic. I co-direct the

The last glaciation of east-central Ellesmere Island, Nunavut: ice dynamics, deglacial chronology, and sea level change

During the last glacial maximum of east-central Ellesmere Island, trunk glaciers inundated the landscape, entering the Smith Sound Ice Stream. Accelerator mass spectrometry (AMS) dates on individual shell fragments in till indicate that the ice advanced after 19 ka BP. The geomorphic and sedimentary signatures left by the trunk glaciers indicate that the glaciers were polythermal. The configuration and chronology of this ice is relevant to the reconstruction of ice core records from northwestern Greenland, the history of iceberg rafting of clastic sediments to northern Baffin Bay, the reopening of the seaway between the Arctic Ocean and Baffin Bay, and the regional variability of arctic paleoenvironments. Deglaciation began with the separation of Ellesmere Island and Greenland ice at fiord mouths ~8-8.5 ka BP. Ice reached fiord heads between 6.5 and 4.4 ka BP. Trunk glacier retreat from the fiords of east-central Ellesmere Island occurred up to 3000 years later than in west coast fiords. This later retreat was favoured by (1) impoundment by the Smith Sound Ice Stream in Kane Basin until ~8.5 ka BP, which moderated the impact of high summer melt recorded in nearby ice cores between ~11.5 and 8.5 ka BP; (2) the shallow bathymetry and narrowness (<2 km) of the east coast fiords, which lowered calving rates following separation of Innuitian and Greenland ice; and (3) the likelihood of higher precipitation along east Ellesmere Island. Glaciers throughout the field area readvanced during the late Holocene. The greater advance of coastal glaciers is attributed to their proximity to the North Water polynya in Baffin Bay.

The last glaciation of east-central Ellesmere Island, Nunavut: ice dynamics, deglacial chronology, and sea level change

The last glaciation of east-central Ellesmere Island, Nunavut: ice dynamics, deglacial chronology, and sea level change

Geological, Archaeological, and Historical Occurrences of Coal, East-Central Ellesmere Island, Arctic Canada

Coal, once widely distributed over most of east-central Ellesmere Island, is only present in restricted outcrops of Eureka Sound Group sediments that survive in the Bache Peninsula Graben (BPG) on ...

Holocene emergence at Cape Herschel, east-central Ellesmere Island, Arctic Canada: implications for ice sheet configuration

Twenty-five radiocarbon age determinations on marine molluscs, basal organic pond sediments, charred remains in archeological sites, and a variety of other materials have allowed the construction of an emergence curve for Cape Herschel, east-central Ellesmere Island (78°35′N, 74°40′W). Only a narrow fringe of land is present between the Prince of Wales Icefield and Smith Sound, yet emergence of the order of 135 m has taken place during the last 8500–8700 radiocarbon years. The highest in situ shells were collected at an elevation of 107.5 m, and ages of 8470 ± 100 BP (GSC-3314) and 8230 ± 70 BP (TO-230) were obtained on this material.The spectacular and fresh-appearing glacial sculpture along both sides of Smith Sound, coupled with the rapid emergence in Holocene time and the fact that the oldest dates on marine shells at the fiord heads to the west are 3000–4000 years younger than those at Cape Herschel, provides convincing evidence that an ice stream filled Smith Sound (> 500 m deep) during the Late Wisconsinan glacial maximum. The Smith Sound Ice Stream drained southward from the Greenland Ice Sheet and the Innuitian Ice Sheet, which were confluent over Kane Basin, and it overrode the top of Pim Island (550 m asl). Massive melt-off of ice must have been occurring at the transition from Pleistocene to Holocene time, and this melting continued until the mid-Holocene, when all investigated outlet glaciers were behind their present positions.

Lake sediments and glacial history in the High Arctic; evidence from east-central Ellesmere Island, Arctic Canada, and from Inglefield Land, Greenland

Lake sediments and glacial history in the High Arctic; evidence from east-central Ellesmere Island, Arctic Canada, and from Inglefield Land, Greenland

Lake sediments and glacial history in the High Arctic; evidence from east-central Ellesmere Island, Arctic Canada, and from Inglefield Land, Greenland

Deciphering glacial history in many High Arctic localities is difficult because: 1) surficial deposits are often thin or nonexistent, 2) vast tracts are underlain by soft and friable bedrock, 3) the churning effects of frost action and slope processes tend to eradicate traces of glaciation, 4) cold based ice caps leave little trace of their former presence, except where marginal drainage channels form on uphill slopes, and 5) significant areas still are covered by glacier ice. Where present, striae show that an area has been glaciated, hut until a technique is devised to determine when a given set of striae was inscribed, or when a striated surface became exposed to daylight (e.g. Phillips et al. 1986: Elmore & Phillips 1987), the timing of the glacial event responsible remains an enigma.

Survey of Vegetated Areas and Muskox Populations in East-Central Ellesmere Island

The results of 1981-84 summer helicopter surveys and ground reconnaissance of east-central Ellesmere Island are presented. This was the first systematic ecological survey to be conducted in this region of the Canadian High Arctic. Central Ellesmere Island is dominated by two large ice fields separated by the deglaciated Sverdrup Pass (79 degrees N). Muskox migrate freely through the 70 km long corridor between the Fosheim Peninsula and some lowlands on the east coast, but large areas of suitable habitat were found unused on the central east coast. Muskox densities in Sverdrup Pass were comparable with those at other arctic sites, as were their reproduction rates (proportion of calves). Vegetated areas (>5 percent cover) constituted only 5 percent of the total surveyed land area and were largely restricted to coastal lowlands and the Sverdrup Pass valley. Key words: Ellesmere Island, Sverdup Pass, high arctic vegetation, polar oases, muskox, muskox habitat

A Reconnaissance Survey of the Environmental Chemistry in East-Central Ellesmere Island, N.W.T.

Snow-pack and surface water samples were collected from east-central Ellesmere Island near Cape Herschel between May and August in 1979-81 to ascertain whether anthropogenic pollution was detectable in a remote pristine arctic environment. Snow-pack samples were analyzed for organochlorine pesticide residues, polynuclear aromatic hydrocarbons, and chlorophenoxy herbicides. Precipitation and surface water samples were analyzed to determine whether the region has been subjected to acid rain. In addition, the surface water samples were analyzed for as many as 35 inorganic parameters to provide background data on the water quality of the region. Measurable concentrations of Lindane (gamma BHC) and its isomer alpha BHC, HEOD (dieldrin), and DDT were detected at a number of sites, but no polynuclear aromatic hydrocarbons (PAHs) or chlorophenoxy herbicides were detected. The pattern of pesticide residues in this remote area of the Arctic is presumptive evidence that the residues are globally dispersed through the atmosphere. Only copper and the lithophilic metals aluminum and iron were consistently detectable in the snow-pack and surface water samples; all other metals were at or below their detection limits. Thus anthropogenic inputs of metal contaminants such as arsenic, cadmium, lead, mercury, selenium, and vanadium, via atmospheric deposition, were not detected in this region. Although acid rain was not in evidence in the study area, the surface waters of the local ponds and lakes, many of which are ombrogenic, are potentially susceptible to changes in the acidity of the atmospheric aerosol of the high Arctic. Key words: snow-pack, precipitation, pesticides, PAHs, rain, water chemistry, metals, Arctic, Ellesmere Island

Bedrock Weathering Features in a Portion of Eastern High Arctic Canada: Their Nature and Significance

Highly-weathered Pre-Cambrian bedrock has been reported from scattered localities across Arctic Canada during the past decade. As part of a study on weathering processes under arid conditions, field studies are reported on-similar terrain in the Alexandra Fjord-Cape Herschel area of east-central Ellesmere Island. Features examined and sampled in both near-coastal and upland positions include grus, tor-like forms, weathering pits, and tafoni. Factors influencing their development and preservation are reviewed. Particular emphasis is placed on the influence of bedrock lithology and mineralogy (in this case, hornblende content) on the intensity of physical disintegration under cold arid conditions. Chemical analyses and petrographic data are presented in support of this observation. Preservation of certain remnant weathering features in upland summit areas under cold-based glacial ice is postulated.

Silurian Stratigraphic Sections at Cape Tyson, Offley Island, and Cape Schuchert, Northwest Greenland: ABSTRACT

The Silurian strata of northwest Greenland consist of an intricate assemblage of graptolitic rocks and limestones of varied facies deposited at the seaward edge of a carbonate platform that covered most of northern Greenland during Silurian time. Facies changes are abrupt and the formations are in part facies equivalents of each other. The Offley Island consists of biostromal and biohermal limestones and associated calcarenites and limestone conglomerates. The Schuchert is composed primarily of somewhat argillaceous calcisiltites, but includes minor biostromal and biohermal limestones and related calcarenites. The graptolitic rocks are assigned to the Phillips and consist of calcareous shale and mudstone, chert, argillaceous limesto e, and local strings of small bioherms. The term Cape Tyson Formation is considered obsolete. All the rocks exposed at the studied localities are of about late Llandovery age, but younger and older Silurian rocks may be present elsewhere in northern Greenland. Extensive development of biostromal and biohermal rocks may be characteristic of the seaward edge of the Silurian carbonate platform in Greenland and the Canadian Arctic Islands. The position of the edge can be traced from Greenland to east-central Ellesmere Island and Grinnell Peninsula to Cornwallis Island, from there westward south of Bathurst Island and through southern Melville Island. End_of_Article - Last_Page 2499------------