NOTES ON NEARCTIC HEPATICAE XVIII NEW LOPHOZIACEAE FROM THE ARCTIC ARCHIPELAGO OF CANADA

1961 ◽  
Vol 39 (4) ◽  
pp. 965-992 ◽  
Author(s):  
Rudolf M. Schuster
Keyword(s):  
American Literature ◽  
High Arctic ◽  
Living Condition ◽  
Western Hemisphere ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Widespread Distribution ◽  
The North ◽  
Difficult Genus

The difficult genus Lophozia, of widespread distribution in the cooler and cold regions of the northern hemisphere, includes a high number of technical species, some of which are very poorly understood. During the summer of 1955 the writer collected extensively on the north coast of Ellesmere Island and was able to study, in the living condition, the high-arctic representatives of this genus. Four species not previously found in the Arctic Archipelago of Canada, three of which are new to the western hemisphere, were collected. Two of these, L. groenlandica and L. opacifolia, are first reported from the Canadian Archipelago in this paper. Two others, L. pellucida and L. hyperarctica, appear to be new to science. These belong to the subgenera Lophozia and Massula, respectively. Since these species are not alluded to in my "Conspectus" of 1951, and since no treatment of them exists in the American literature, the following detailed treatment is provided.

scholarly journals Snowfall and Oxygen-Isotope Variations off the North Coast of Ellesmere Island, N.W.T., Canada

1987 ◽  
Vol 33 (114) ◽  
pp. 195-199 ◽  
Author(s):  
Martin O. Jeffries ◽  
H. Roy Krouse
Keyword(s):  
Arctic Ocean ◽  
High Arctic ◽  
Geographic Region ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Snow Pack ◽  
The North ◽  
Winter Snow ◽  
The Mean

AbstractSnow-pack along the land-fast ice fringe off the north coast of Ellesmere Island was generally characterized by depth-hoar overlain by dense snow and wind slab. Mean snow depth in the study area was 0.54 m (1982-85) and the mean δ18O value of the snow-pack was -31.3˚/00. Isotope data were not obtained previously for this geographic region and, therefore, complement a previous study of δ18O variations in High Arctic snow (Koerner, 1979). The data are consistent with an Arctic Ocean moisture source. The δ18O profiles show seasonal variations, with winter snow being more depleted in 18O than fall and spring snow. However, the δ18O profiles are dominated by a trend to higher δ18O values with increasing depth. This is attributed to a decrease in δ18O values as condensation temperatures fall during the autumn-winter accumulation period. During this time, there is also a change from relatively open to almost complete ice cover in the Arctic Ocean. The change in evaporation conditions and consequent effect on δ values gives rise to a sharp discontinuity in the δ18O profiles and a bi-modal δ18O frequency distribution. The bi-modal distribution is reinforced by a secondary isotope fractionation that occurs during depth-hoar formation. This isotope effect leads to a wider δ18O range but does not significantly alter the mean δ18O value.

scholarly journals Snowfall and Oxygen-Isotope Variations off the North Coast of Ellesmere Island, N.W.T., Canada

1987 ◽  
Vol 33 (114) ◽  
pp. 195-199 ◽  
Author(s):  
Martin O. Jeffries ◽  
H. Roy Krouse
Keyword(s):  
Arctic Ocean ◽  
High Arctic ◽  
Geographic Region ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Snow Pack ◽  
The North ◽  
Winter Snow ◽  
The Mean

AbstractSnow-pack along the land-fast ice fringe off the north coast of Ellesmere Island was generally characterized by depth-hoar overlain by dense snow and wind slab. Mean snow depth in the study area was 0.54 m (1982-85) and the mean δ18O value of the snow-pack was -31.3˚/00. Isotope data were not obtained previously for this geographic region and, therefore, complement a previous study of δ18O variations in High Arctic snow (Koerner, 1979). The data are consistent with an Arctic Ocean moisture source. The δ18O profiles show seasonal variations, with winter snow being more depleted in18O than fall and spring snow. However, the δ18O profiles are dominated by a trend to higher δ18O values with increasing depth. This is attributed to a decrease in δ18O values as condensation temperatures fall during the autumn-winter accumulation period. During this time, there is also a change from relatively open to almost complete ice cover in the Arctic Ocean. The change in evaporation conditions and consequent effect on δ values gives rise to a sharp discontinuity in the δ18O profiles and a bi-modal δ18O frequency distribution. The bi-modal distribution is reinforced by a secondary isotope fractionation that occurs during depth-hoar formation. This isotope effect leads to a wider δ18O range but does not significantly alter the mean δ18O value.

The last glaciation of Marvin Peninsula, northern Ellesmere Island, High Arctic, Canada

1989 ◽  
Vol 26 (12) ◽  
pp. 2578-2590 ◽  
Author(s):  
Donald S. Lemmen
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
North Coast ◽  
Radiocarbon Dates ◽  
The North ◽  
Last Glaciation ◽  
Ice Retreat ◽  
Late Wisconsinan ◽  
Glaciomarine Sediments ◽  
North And South

The limit of the last glaciation on Marvin Peninsula, northernmost Ellesmere Island, is recorded by extensive ice-marginal landforms and early Holocene glaciomarine sediments. While glaciers occupied most valleys on the peninsula, other areas remained ice free, as did most of the adjacent fiords. Beyond the ice limit, sparse erratics and degraded meltwater channels within weathered bedrock are evidence of older, more extensive glaciation(s). Shorelines and marine shells 50 m above the limit of the Holocene sea along the north coast relate to these older glacial events.Thirty-four new radiocarbon dates provide a chronology of ice buildup and retreat. Glaciers reached their limit after 23 ka, and locally as late as 11 ka. This was achieved by both expansion of existing glaciers and accumulation on plateau and lowland sites, which are presently ice free. Late Wisconsinan climate was characterized by cold and extreme aridity. Five dates ranging from 11 to 31 ka BP on subfossil bryophytes suggest that ice-free areas were biologically productive throughout the last glaciation. Ice retreat and postglacial emergence had begun by 9.5 ka and was associated with a marked climatic amelioration. The deglacial chronology confirms a pronounced disparity in the timing of ice retreat on the north and south sides of the Grant Land Mountains.

The Lepidoptera of Greenland; Some Geographic Considerations

1966 ◽  
Vol 98 (11) ◽  
pp. 1135-1144 ◽  
Author(s):  
J. A. Downes
Keyword(s):  
North America ◽  
Vascular Plants ◽  
Large Fraction ◽  
High Arctic ◽  
Oceanic Island ◽  
Ellesmere Island ◽  
The Arctic ◽  
Baffin Island ◽  
The North ◽  
Almost All

AbstractFrom the revised list of the Lepidoptera of Greenland and from recent work in Ellesmere Island it is shown that almost all the species found in high arctic Canada occur also in Greenland, predominantly in the north, and that this high arctic element constitutes a large fraction of the fauna of Greenland as a whole. It is suggested that this part of the fauna originated entirely from the nearctic by the little-interrupted land route across the arctic islands. The poverty of southerly Lepidoptera in Greenland stands in sharp contrast. It is illustrated by a comparison with the vascular plants and by other comparisons with the Lepidoptera found in the corresponding life zones in North America, and this section of the paper includes the first published list of the Lepidoptera of Baffin Island. It is suggested that this southerly fauna is of adventitious origin, by casual dispersal from overseas (Labrador, Iceland) or perhaps in a few cases by introduction by man. Thus Greenland, in respect of its fauna of southerly type, is an oceanic island of post-glacial age. Similar evidence suggests that Iceland also has been populated mainly in the same way. The conclusions derived from the Lepidoptera apply to several other groups of insects and also to the mammals, including man.

North Greenland ice islands

Polar Record ◽  
1989 ◽  
Vol 25 (154) ◽  
pp. 207-212 ◽  
Author(s):  
A. K. Higgins
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Surface Topography ◽  
Ellesmere Island ◽  
The Arctic ◽  
North Coast ◽  
Ice Shelves ◽  
The North ◽  
The Arctic Ocean ◽  
North Greenland

AbstractLarge tabular icebergs derived from the glaciers which drain the north fringe of Greenland's Inland Iceoccur in many North Greenland fjords. Many have undulating surface topography resembling that of the ice islands calved from Ellesmere Island ice shelves. Semi-permanent sea ice in North Greenland fjords often prevents the escape of bergs, except in exceptional summers several decades apart, when the fjord ice melts completely and some bergs may reach the Arctic Ocean. Other possible sources for ice islands are small ice shelves and local glaciers along the north coast of Greenland.

scholarly journals New constraints on the age, geochemistry, and environmental impact of High Arctic Large Igneous Province magmatism: Tracing the extension of the Alpha Ridge onto Ellesmere Island, Canada

2020 ◽  
Author(s):  
T.V. Naber ◽  
S.E. Grasby ◽  
J.P. Cuthbertson ◽  
N. Rayner ◽  
C. Tegner
Keyword(s):  
Volcanic Rocks ◽  
High Arctic ◽  
Ellesmere Island ◽  
Large Igneous Province ◽  
The Arctic ◽  
Trace Element Geochemistry ◽  
Volcanic Complex ◽  
Northern Coast ◽  
Element Geochemistry ◽  
Igneous Province

The High Arctic Large Igneous Province (HALIP) represents extensive Cretaceous magmatism throughout the circum-Arctic borderlands and within the Arctic Ocean (e.g., the Alpha-Mendeleev Ridge). Recent aeromagnetic data shows anomalies that extend from the Alpha Ridge onto the northern coast of Ellesmere Island, Nunavut, Canada. To test this linkage we present new bulk rock major and trace element geochemistry, and mineral compositions for clinopyroxene, plagioclase, and olivine of basaltic dykes and sheets and rhyolitic lavas for the stratotype section at Hansen Point, which coincides geographically with the magnetic anomaly at northern Ellesmere Island. New U-Pb chronology is also presented. The basaltic and basaltic-andesite dykes and sheets at Hansen Point are all evolved with 5.5−2.5 wt% MgO, 48.3−57.0 wt% SiO2, and have light rare-earth element enriched patterns. They classify as tholeiites and in Th/Yb vs. Nb/Yb space they define a trend extending from the mantle array toward upper continental crust. This trend, also including a rhyolite lava, can be modeled successfully by assimilation and fractional crystallization. The U-Pb data for a dacite sample, that is cut by basaltic dykes at Hansen Point, yields a crystallization age of 95.5 ± 1.0 Ma, and also shows crustal inheritance. The chronology and the geochemistry of the Hansen Point samples are correlative with the basaltic lavas, sills, and dykes of the Strand Fiord Formation on Axel Heiberg Island, Nunavut, Canada. In contrast, a new U-Pb age for an alkaline syenite at Audhild Bay is significantly younger at 79.5 ± 0.5 Ma, and correlative to alkaline basalts and rhyolites from other locations of northern Ellesmere Island (Audhild Bay, Philips Inlet, and Yelverton Bay West; 83−73 Ma). We propose these volcanic occurrences be referred to collectively as the Audhild Bay alkaline suite (ABAS). In this revised nomenclature, the rocks of Hansen Point stratotype and other tholeiitic rocks are ascribed to the Hansen Point tholeiitic suite (HPTS) that was emplaced at 97−93 Ma. We suggest this subdivision into suites replace the collective term Hansen Point volcanic complex. The few dredge samples of alkali basalt available from the top of the Alpha Ridge are akin to ABAS in terms of geochemistry. Our revised dates also suggest that the HPTS and Strand Fiord Formation volcanic rocks may be the hypothesized subaerial large igneous province eruption that drove the Cretaceous Ocean Anoxic Event 2.

Chapter 20 Paleogene history

1997 ◽  
Vol 17 (1) ◽  
pp. 388-417
Keyword(s):  
Early Cretaceous ◽  
The Arctic ◽  
North Coast ◽  
Western Coast ◽  
Central Basin ◽  
Oblique Collision ◽  
The North ◽  
Western Border ◽  
Paleozoic Rocks ◽  
West Spitsbergen

The Paleogene chapter of Svalbard history is a quite distinct one. It begins with an unconformity, albeit a sub-parallel one representing a late Cretaceous hiatus. Resting on Albian and older strata, the Van Mijenfjorden Group of six formations totals a thickness of about 2500 m in the Central Basin of Spitsbergen. The outcrop is ringed by Early Cretaceous strata in a broad syncline (Fig. 20.1). The strata are largely non-marine, coal-bearing sandstones, with interbedded marine shales and they range in age through Paleocene and Eocene.From latest Paleocene through Eocene time the West Spitsbergen Orogeny caused (Spitsbergian) deformation along the western border of the Central Basin, but it is most conspicuous in the folding and thrusting of Carboniferous through Early Cretaceous rocks. The orogen extended westwards to and beyond the western coast of central and southern Spitsbergen including Precambrian and Early Paleozoic rocks, which had already been involved in earlier tectogenesis. The eastward-verging thrusting extended beneath the Tertiary basin and reactivated older faults to the east.In the wider context Svalbard, adjacent to the north coast of Greenland, had been an integral part of Pangea from Carboniferous through Cretaceous time. The northward extension of the Atlantic opening reached and initiated the spreading of the Arctic Eurasia Basin at the beginning of the Paleogene Period. This led to the separation of Svalbard together with the Barents Shelf and northern Europe from Greenland by dextral strike-slip transform faulting. In the course of this progression, oblique collision between northeast Greenland and Svalbard caused

Radiogenic Isotope Signatures of Holocene Sediments from Kane Basin: Linkage with the Re-opening and Evolution of Nares Strait

2021 ◽  
Author(s):  
Lina Madaj ◽  
Friedrich Lucassen ◽  
Claude Hillaire-Marcel ◽  
Simone A. Kasemann
Keyword(s):  
Ellesmere Island ◽  
The Arctic ◽  
Baffin Bay ◽  
Low Salinity ◽  
The Core ◽  
The Past ◽  
Nares Strait ◽  
The North ◽  
Sediment Input ◽  
Detrital Sediment

<p>The re-opening of the Arctic Ocean-Baffin Bay gateway through Nares Strait, following the Last Glacial Maximum, has been partly documented, discussed and revised in the past decades. The Nares Strait opening has led to the inception of the modern fast circulation pattern carrying low-salinity Arctic water towards Baffin Bay and further towards the Labrador Sea. This low-salinity water impacts thermohaline conditions in the North Atlantic, thus the Atlantic Meridional Overturning Circulation. Available land-based and marine records set the complete opening between 9 and 7.5 ka BP [1-2], although the precise timing and intensification of the southward flowing currents is still open to debate. A recent study of a marine deglacial sedimentary record from Kane Basin, central Nares Strait, adds information about subsequent paleoceanographic conditions in this widened sector of the strait and proposed the complete opening at ~8.3 ka BP [3].</p><p>We present complementary radiogenic strontium, neodymium and lead isotope data of the siliciclastic detrital sediment fraction of this very record [3] further documenting the timing and pattern of Nares Strait opening from a sediment provenance approach. The data permit to distinguish detrital material from northern Greenland and Ellesmere Island, transported to the core location from both sides of Nares Strait. Throughout the Holocene, the evolution of contributions of these two sources hint to the timing of the ice break-up in Kennedy Channel, north of Kane Basin, which led to the complete opening of Nares Strait [3]. The newly established gateway of material transported to the core location from the north via Kennedy Channel is recorded by increased contribution of northern Ellesmere Island detrital sediment input. This shift from a Greenland (Inglefield Land) dominated sediment input to a northern Ellesmere Island dominated sediment input supports the hypothesis of the newly proposed timing of the complete opening of Nares Strait at 8.3 ka BP [3] and highlights a progressive trend towards modern-like conditions, reached at about 4 ka BP.</p><p>References:</p><p>[1] England (1999) Quaternary Science Reviews, 18(3), 421–456. [2] Jennings et al. (2011) Oceanography, 24(3), 26-41. [3] Georgiadis et al. (2018) Climate of the Past, 14 (12), 1991-2010.</p>

scholarly journals An estimate of ice wedge volume for a High Arctic polar desert environment, Fosheim Peninsula, Ellesmere Island

2018 ◽  
Vol 12 (11) ◽  
pp. 3589-3604 ◽  
Author(s):  
Claire Bernard-Grand'Maison ◽  
Wayne Pollard
Keyword(s):  
Satellite Imagery ◽  
Regional Scale ◽  
High Arctic ◽  
Ellesmere Island ◽  
The Arctic ◽  
Ground Ice ◽  
Polar Desert ◽  
Ice Volume ◽  
Carbon Release ◽  
Wedge Volume

Abstract. Quantifying ground-ice volume on a regional scale is necessary to assess the vulnerability of permafrost landscapes to thaw-induced disturbance like terrain subsidence and to quantify potential carbon release. Ice wedges (IWs) are a ubiquitous ground-ice landform in the Arctic. Their high spatial variability makes generalizing their potential role in landscape change problematic. IWs form polygonal networks that are visible on satellite imagery from surface troughs. This study provides a first approximation of IW ice volume for the Fosheim Peninsula, Ellesmere Island, a continuous permafrost area characterized by polar desert conditions and extensive ground ice. We perform basic GIS analyses on high-resolution satellite imagery to delineate IW troughs and estimate the associated IW ice volume using a 3-D subsurface model. We demonstrate the potential of two semi-automated IW trough delineation methods, one newly developed and one marginally used in previous studies, to increase the time efficiency of this process compared to manual delineation. Our methods yield acceptable IW ice volume estimates, validating the value of GIS to estimate IW volume on much larger scales. We estimate that IWs are potentially present on 50 % of the Fosheim Peninsula (∼3000 km2), where 3.81 % of the top 5.9 m of permafrost could be IW ice.

scholarly journals Aspects of the Glaciology of Meighen Island, Northwest Territories, Canada

1965 ◽  
Vol 5 (40) ◽  
pp. 399-410 ◽  
Author(s):  
K. C. Arnold
Keyword(s):  
Snow Accumulation ◽  
The Arctic ◽  
North Coast ◽  
Ice Cap ◽  
The North ◽  
Four Seasons ◽  
Northern Half ◽  
Northern Edge ◽  
Summer Temperatures ◽  
Made In

Abstract Meighen Island lies in the centre of the north coast of the Queen Elizabeth Islands and fronts on the Arctic Ocean. An ice cap of about 76 km.2 covers about one-tenth of the island. Its greatest thickness of 150 m. occurs under the summit, near the south end, which was 268 m. above sea-level in 1960. The northern half of the ice cap is less than 30 m. thick; and the total volume is of the order of 2,000 × 106 m.3. Precipitation is low in the northern Queen Elizabeth Islands, and Meighen Island lies in an area where summer temperatures are lowest. In the winters of 1959–60, 1960–61 and 1961–62, the snow accumulation was 12.6, 18.2 and 14.1 cm. of water equivalent. Some snowfall remained on the higher part of the ice cap in the cold summer of 1961; but the ice cap diminished in volume in each year; by 36 × 106, 72 × 106, 22 × 106 and 91 × 106 m.3 in the 1959, 1960, 1961 and 1962 ablation seasons. If the conditions of these four seasons were maintained the ice cap would disappear in about 100 yr. However, a radio-carbon dating of a saxifrage exposed by the retreat of the ice from a small nunatak near the northern edge gave a date of less than 100 yr., and it appears that the existence of the ice cap might be sensitively related to recent climatic change. Careful surveys were made in 1959, 1960 and 1961 in an attempt to detect movement in the ice cap. Unequivocal evidence is not available from these surveys; but the stake network has been maintained and another survey has recently been completed.

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