Flowers, insects, and pollination ecology in the Canadian high Arctic

Polar Record ◽  
1973 ◽  
Vol 16 (104) ◽  
pp. 667-674 ◽  
Author(s):  
Peter G. Kevan
Keyword(s):  
High Arctic ◽  
Pollination Ecology ◽  
Ellesmere Island ◽  
Ecological Problem ◽  
Canadian High Arctic ◽  
Mountain Ranges ◽  
The North ◽  
Low Arctic ◽  
Work Done

The following report is based on work done in conjunction with the Canadian “Operation Hazen-Tanquary” at Hazen Camp (81° 49'N, 71° 18'W), Ellesmere Island, NWT, in the summers of 1966, 1967, and 1968. Hazen Camp offers an excellent high Arctic site because of the extensive facilities available and because the botany and entomology are comparatively well known and some insect-flower relationships there have already been considered. Furthermore, the Lake Hazen trough, sheltered by mountain ranges to the north, enjoys less cloudy and more benign summers than most high Arctic localities. These factors contribute to the support of a biota that is relatively rich for the high Arctic, even though the ecosystem is considerably simpler than in the low Arctic. There are only about 75 species of Dicotyledoneae and about 250 species of Arthropoda to consider, which makes it possible for one man to investigate such a broad ecological problem as insect-flower relations.

Glacier dynamics and paleoclimatic change during the last glaciation of eastern Ellesmere Island, Canada

1996 ◽  
Vol 33 (5) ◽  
pp. 779-799 ◽  
Author(s):  
John England
Keyword(s):  
Late Quaternary ◽  
Ice Core ◽  
Ice Cores ◽  
High Arctic ◽  
Ellesmere Island ◽  
Canadian High Arctic ◽  
Regional Warming ◽  
Ice Dynamics ◽  
The North ◽  
Glacier Dynamics

A 300 km transect along the east coast of Ellesmere Island fills a major gap in the late Quaternary data base of the Canadian High Arctic. The last glacial maximum (LGM) is marked by prominent moraines and meltwater channels that terminate within 30 km of modern ice margins. Shells in glaciomarine deposits, collected beyond the LGM, indicate deglaciation by more extensive ice prior to 35 ka BP. More than 60 14C dates from glaciomarine sediments provide a chronology for past ice dynamics during the LGM. To the north, while many areas remained ice free due to severe aridity, several glaciers remained in contact with the sea until 7.1 ka BP. Farther south, most glaciers reached the coast and significantly infilled several fiords. This southward increase in glacier extent is due to larger glacial catchment basins and increased precipitation towards storm tracks in northern Baffin Bay. The earliest dates on deglaciation along the transect range from 8.1 to 7.7 ka BP. Initial retreat was controlled by the extent of the marine-based ice margins, which were destabilized by calving. Once landward of the sea, many glaciers stabilized until ~6.5 ka BP. Considerable interfiord variability in glacier dynamics is apparent. A paleoclimatic model is proposed linking past glacier activity in the Canadian High Arctic with the available ice core record. Greenland ice cores show that colder intervals, with depleted δ18O, were associated with reduced precipitation and storminess, which may have constrained ice buildup prior to ~15 ka BP. In contrast, the abrupt rise in δ18O after ~15 ka signals the onset of regional warming associated with increased storminess and precipitation (up to 200%). This may have occasioned a late buildup of High Arctic glaciers, which remained close to the last ice limit well into the Holocene.

Paleomagnetism and U–Pb geochronology of the Clarence Head dykes, Arctic Canada: orthogonal emplacement of mafic dykes in a large igneous province

2009 ◽  
Vol 46 (3) ◽  
pp. 155-167 ◽  
Author(s):  
Steven W. Denyszyn ◽  
Don W. Davis ◽  
Henry C. Halls
Keyword(s):  
Remanent Magnetization ◽  
High Arctic ◽  
Large Igneous Province ◽  
Dyke Swarm ◽  
Canadian High Arctic ◽  
The North ◽  
Igneous Province ◽  
The Difference ◽  
Age Range ◽  
Chemical Remanent Magnetization

The north–south-trending Clarence Head dyke swarm, located on Devon and Ellesmere Islands in the Canadian High Arctic, has a trend orthogonal to that of the Neoproterozoic Franklin swarm that surrounds it. The Clarence Head dykes are dated by the U–Pb method on baddeleyite to between 716 ± 1 and 713 ± 1 Ma, ages apparently younger than, but within the published age range of, the Franklin dykes. Alpha recoil in baddeleyite is considered as a possible explanation for the difference in ages, but a comparison of the U–Pb ages of grains of equal size from both swarms suggests that recoil distances in baddeleyite are lower than those in zircon and that the Clarence Head dykes are indeed a distinctly younger event within the period of Franklin magmatism. The Clarence Head dykes represent a large swarm tangential to, and cogenetic with, a giant radiating dyke swarm ∼800 km from the indicated source. The preferred mechanism for the emplacement of the Clarence Head dykes is the exploitation of concentric zones of extension around a depleting and collapsing plume source. While the paleomagnetism of most Clarence Head dykes agrees with that of the Franklin dykes, two dykes have anomalous remanence directions, interpreted to be a chemical remanent magnetization carried by pyrrhotite. The pyrrhotite was likely deposited from fluids mobilized southward from the Devonian Ellesmerian Orogeny to the north that used the interiors of the dykes as conduits and precipitated pyrrhotite en route.

scholarly journals Dynamics of Ice-Island Motion Near the Coast of Axel Heiberg Island, Canadian High Arctic

1989 ◽  
Vol 12 ◽  
pp. 152-156 ◽  
Author(s):  
W.M. Sackinger ◽  
M.O. Jeffries ◽  
H. Tippens ◽  
F. Li ◽  
M. Lu
Keyword(s):  
Surface Wind ◽  
High Arctic ◽  
The Arctic ◽  
Movement Direction ◽  
Canadian High Arctic ◽  
North West ◽  
The North ◽  
Pack Ice ◽  
Axel Heiberg Island ◽  
Ice Force

The largest ice island presently known to exist in the Arctic Ocean has a mass of about 700 × 106 tonnes, an area of about 26 km2, and a mean thickness of 42.5 m. Known as Hobson’s Ice Island, this large ice feature has been tracked almost continuously since August 1983 with a succession of Argos buoys. In this paper, two particular ice-island movement episodes near the north-west coast of Axel Heiberg Island are described: 6–16 May 1986 and 14–21 June 1986. Each movement episode is analyzed in terms of the forces acting on the ice island, including wind shear, water drag, water shear, Coriolis force, sea-surface tilt, and pack-ice force. Ice-island movement is generally preceded by an offshore surface wind, and a threshold wind speed of 6 m s°1 appears to be necessary to initiate ice-island motion. An angle of 50° between surface wind and ice-island movement direction is noted during one episode. The pack-ice force, which appears to be the dominant arresting factor of ice-island motion for these two episodes, varies from 100° to 180° to the left of the ice-island velocity direction, depending upon whether the ice island is accelerating or decelerating.

scholarly journals Equilibrium-Line Altitudes, Mass Balance, and July Freezing-Level Heights in the Canadian High Arctic

1975 ◽  
Vol 14 (71) ◽  
pp. 267-274 ◽  
Author(s):  
R. S. Bradley
Keyword(s):  
Mass Balance ◽  
High Arctic ◽  
Equilibrium Line ◽  
Canadian High Arctic ◽  
North West ◽  
Freezing Level ◽  
Ice Cap ◽  
The North ◽  
Devon Ice Cap ◽  
Axel Heiberg Island

Equilibrium-line altitudes on the White Glacier, Axel Heiberg Island, and the north-west sector of the Devon Ice Cap are shown to be closely related to mean July freezing-level heights at nearby upper-air weather stations. An inverse relationship between July freezing-level heights and mass balance on the Devon Ice Cap is also shown. Reasons for such correlations are suggested and some limitations of the relationship are outlined. Recent lowering of the freezing level in July is discussed in relation to the theoretical “steady-state” equilibrium-line altitudes in the Canadian high Arctic. It is suggested that positive mass-balance years have predominated over a large part of northern Ellesmere Island and north-central Axel Heiberg Island since 1963, and some glaciological evidence supporting this hypothesis is given.

Ellesmerian and Eurekan fault tectonics at the northern margin of Ellesmere Island (Canadian High Arctic)

2013 ◽  
Vol 164 (1) ◽  
pp. 81-105 ◽  
Author(s):  
Karsten Piepjohn ◽  
Werner von Gosen ◽  
Andreas Läufer ◽  
William C. McClelland ◽  
Solveig Estrada
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
Canadian High Arctic ◽  
Northern Margin ◽  
Fault Tectonics

scholarly journals Evidence of a Periodic Ice-Cliff Avalanche on North-West Ellesmere Island, N.W.T., Canadian High Arctic

1987 ◽  
Vol 33 (113) ◽  
pp. 68-71 ◽  
Author(s):  
D. J. A. Evans ◽  
T. G. Fisher
Keyword(s):  
High Arctic ◽  
Ellesmere Island ◽  
Canadian High Arctic ◽  
Periodic Activity ◽  
North West ◽  
Ice Cap ◽  
Melt Water

AbstractEvidence of a recent (1985) ice-cliff avalanche from an outlet lobe of a small plateau ice cap on north-west Ellesmere Island is discussed. Former avalanche events are evidenced by debris lying outside the 1985 avalanche material. Periodic activity seems to be linked to the build-up of melt water in the crevasses of the outlet lobe during the melt season. The exact magnitude and frequency of events are unknown. Some implications to geomorphology and the sedimentology of sub-polar glaciers are discussed.

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