Ice - Wedges As Indicators of Recent Climatic Change, western Arctic Coast

1976 ◽  
Author(s):  
J R Mackay
Keyword(s):  
Climatic Change ◽  
Recent Climatic Change ◽  
Western Arctic ◽  
Arctic Coast

The Growth of Pingos, Western Arctic Coast, Canada

1973 ◽  
Vol 10 (6) ◽  
pp. 979-1004 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Growth Rate ◽  
Pore Water ◽  
Closed System ◽  
Water Pressure ◽  
Ice Core ◽  
Growth Stages ◽  
Size And Shape ◽  
Western Arctic ◽  
Arctic Coast ◽  
Strong Control

The growth rates of 11 closed system pingos have been measured, by means of precise levelling of permanent bench marks anchored well down into permafrost, for the 1969–1972 period. As pingo growth decreases from the summit to the base, growth of the ice-core decreases from the center out to the periphery. The pingos have grown up in the bottoms of lakes which have drained rapidly and thus become exposed to permafrost aggradation. The specific site of growth is usually in a small residual pond where permafrost aggradation is retarded. The size and shape of a residual pond exercises a strong control upon the size and shape of the pingo which grows within it. The ice-core thickness equals the sum of the pingo height above the lake flat and the depth of the residual pond in which the pingo grew. Pingos tend to grow higher rather than both higher and wider. Pingos are believed to grow more by means of ice segregation than by the freezing of a pool of water. The water source, and the associated positive pore water pressure, result from permafrost aggradation in sands and silts in the lake bottom under a closed system with expulsion of pore water. The fastest growth rate of an ice-core, for the Western Arctic Coast, is estimated at about 1.5 m/yr, for the first one or two years. After that, the growth rate decreases inversely as the square root of time. The largest pingos may continue to grow for more than 1000 yr. Four growth stages are suggested. At least five pingos have commenced growth since 1935. As an estimate, probably 50 or more pingos are now growing along the coast.

scholarly journals PERFORMANCE OP SAND-FILLED TUBE SHORE PROTECTION TUKTOYAKTUK, NORTH WEST TERRITORIES, CANADA

1982 ◽  
Vol 1 (18) ◽  
pp. 114
Author(s):  
V.K. Shah
Keyword(s):  
Large Majority ◽  
Natural Stone ◽  
Alternative Form ◽  
Shore Protection ◽  
Experimental Basis ◽  
North West ◽  
Western Arctic ◽  
Arctic Coast ◽  
North West Territories ◽  
North Latitude

Seawalls, revetments and groynes designed to protect shorelines require normally timber, natural stone or concrete for their construction. In Tuktoyaktuk, none of these materials is available and to avoid excessive costs, an alternative form of construction, using long sausage shaped tubes filled with sand, was devised on an experimental basis. Tuktoyaktuk is situated on the eastern side of Kugmallit Bay in the Western Arctic at north latitude of 69 deg. 27' and west longitude of 133 deg. 02'. It is approximately 90 miles north of Inuvik and 1450 miles northwest of Edmonton (figure 1). The area is mainly comprised of a long, narrow, boot-shaped peninsula oriented in approximately north-south direction, a complex lagoon, which has been developed as a harbour, east of the peninsula and an island straddling the mouth of the lagoon (figure 2). Certain dwellings exist at the southern and southeasterly shores of Tuktoyaktuk Harbour. A large majority of the inhabitants reside in settlements developed on the peninsula and the southern area linking the peninsula with the mainland. Tuktoyaktuk is used as a transfer point linking the Mackenzie River barge transport with coastwide shipping serving the western arctic seaboard and inland settlements and bases. As a result of this the TCJK settlement has grown to be the largest of the western arctic coast settlements.

Ice wedges on hillslopes and landform evolution in the late Quaternary, western Arctic coast, Canada

1995 ◽  
Vol 32 (8) ◽  
pp. 1093-1105 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Active Layer ◽  
Late Quaternary ◽  
Chronological Age ◽  
Bottom Slope ◽  
Thermally Induced ◽  
Landform Evolution ◽  
Ice Wedge ◽  
Western Arctic ◽  
Arctic Coast ◽  
The Mean

In rolling to hilly areas of the western Arctic coast of Canada, anti-syngenetic wedges, which by definition are those that grow on denudational slopes, are the most abundant type of ice wedge. Through prolonged slope denudation, hilltop epigenetic wedges can evolve into hillslope anti-syngenetic wedges, and some bottom-slope anti-syngenetic wedges, by means of deposition from upslope, can evolve into bottom-slope syngenetic wedges. The axis of a hillslope wedge is oriented perpendicular to the slope, so the wedge foliation varies according to the trend of the wedge with respect to the slope. Because the tops of hillslope wedges are truncated by slope recession, the mean chronological age of anti-syngenetic wedge ice decreases with time, so the growth record for an old wedge is incomplete. Summer and winter measurements show that a thermally induced net movement of the active layer of hillslope polygons tends to transport material from their centres towards their troughs independent of the trends of the troughs relative to the slope. Wedge-ice uplift, probably diapiric, has been measured. Some hillslope polygon patterns may predate the development of the present topography. Many Wisconsinan wedges, truncated and buried during the Hypsithermal period, have been reactivated by upward cracking.

The first 7 years (1978–1985) of ice wedge growth, Illisarvik experimental drained lake site, western Arctic coast

1986 ◽  
Vol 23 (11) ◽  
pp. 1782-1795 ◽  
Author(s):  
J. Ross Mackay
Keyword(s):  
Growth Rates ◽  
Linear Expansion ◽  
Temperature Dependent ◽  
Frozen Ground ◽  
Ice Wedge ◽  
Western Arctic ◽  
Arctic Coast ◽  
Coefficient Of Linear Expansion ◽  
Lake Site ◽  
Crack Widths

A large lake, measuring 600 m × 300 m and with a depth of nearly 5 m, was artificially drained on 13 August 1978. Observations on the formation, width, and depth of thermal contraction cracks for the first 7 years show that the crack profiles and ice wedge growth rates differ markedly from those of old ice wedges reported in the literature. The first winter's cracks had box-like profiles, with surface widths to 10 cm and depths to 2.5 m. Some cracks continued to widen and deepen, once opened in early winter, and then narrowed or even closed completely in summer. Mean growth rates for the ice wedges for the first few years have been as much as 3.5 cm/year. Temperature gradients at the time of first cracking have been in the range of 10–15 °C/m. The growth rate of young ice wedges is site specific and temperature dependent, varying with factors such as the temperature gradient, vegetation, and snow cover, so an estimate of the age of an ice wedge from its width will usually be impossible. A study of crack widths indicates that the apparent coefficient of linear expansion of frozen ground may be several times that of ice. Upward cracking has been proven.

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