A Landscape Zonation for the Southern and Central Mackenzie River Valley based on Terrain Permafrost Characteristics

1973 ◽  
Vol 10 (12) ◽  
pp. 1843-1854 ◽  
Author(s):  
C. B. Crampton
Keyword(s):  
Active Layer ◽  
Relative Abundance ◽  
River Valley ◽  
Permafrost Zone ◽  
The Past ◽  
Discontinuous Permafrost ◽  
Mackenzie River

A landscape zonation is presented for the southern and central Mackenzie River valley, based on observed changes in permafrost characteristics of selected terrain types, with changing climatic implications. The relative abundance of lichen on specified terrain types suggests the thickness of the active layer within the discontinuous permafrost zone, and is a useful guide in air photograph interpretation for extensive mapping of landscape–permafrost realtionships between localities of ground inspection. Widespread, fossil, cryoturbated terrain supports the contention that today's climate in the study area is less severe than that in the past.

The response (1958-1997) of permafrost and near-surface ground temperatures to forest fire, Takhini River valley, southern Yukon Territory

1998 ◽  
Vol 35 (2) ◽  
pp. 184-199 ◽  
Author(s):  
C R Burn
Keyword(s):  
Active Layer ◽  
Forest Fires ◽  
Ground Surface ◽  
Yukon Territory ◽  
River Valley ◽  
Permafrost Degradation ◽  
Near Surface ◽  
Surface Conditions ◽  
Mean Temperature ◽  
Discontinuous Permafrost

Forest fires in permafrost areas often modify ground surface conditions, causing deepening of the active layer and thawing of near-surface permafrost. Takhini River valley lies in the discontinuous permafrost zone of southern Yukon Territory. The valley floor is covered by glaciolacustrine deposits, which are locally ice rich. In 1958 extensive forest fires burned most of the vegetation and the soil organic horizon in the valley, but, 50 km west of Whitehorse, 1 km2 of spruce forest adjacent to the Alaska Highway escaped burning. Permafrost beneath this stand of trees is in equilibrium with surface conditions: the active layer is 1.4 m thick, the base of permafrost is at 18.5 m, the annual mean temperature at the top of permafrost (1.5 m) is -0.8°C, and the temperature gradient in permafrost is constant with depth. At burned sites nearby there has been little regeneration of forest vegetation since the fire, and long-term permafrost degradation has occurred. At one burned site, the permafrost table is more than 3.75 m below the ground surface, the mean annual ground temperature is -0.2°C or warmer throughout the profile, the annual mean temperature at 1.5 m is 0.1°C, and permafrost is thawing from top and bottom. A simplified analytical model for thawing of permafrost indicates that over a millennium will be required to degrade permafrost completely at this site, if thawing proceeds from the top down. The result demonstrates the persistence of ice-rich permafrost a few metres below the ground surface, even at sites near the southern margin of permafrost in Canada.

SOME CHARACTERISTICS OF CRYIC ORGANIC SOILS IN NORTHERN MANITOBA

1972 ◽  
Vol 52 (3) ◽  
pp. 485-496 ◽  
Author(s):  
C. TARNOCAI
Keyword(s):  
Active Layer ◽  
Black Spruce ◽  
Permafrost Zone ◽  
Organic Soils ◽  
High Concentration ◽  
Water Ice ◽  
Discontinuous Permafrost ◽  
Significant Difference ◽  
Exchangeable Magnesium ◽  
Ice Content

Two commonly occurring, perennially frozen, organic soils were studied, one from the south-west part of the Discontinuous Permafrost Zone and the other from the Continuous Permafrost Zone of the Hudson Bay Lowland in northern Manitoba. These soils had a characteristic domed or slightly elevated topography with a dense cover of black spruce (Picea mariana (Mill.) BSP.), Ledum groenlandicum Oeder, feathermoss, and sphagnum moss. The water content of the active layer was found to be much lower than the water (ice) content of the frozen layer. The exchangeable calcium and hydrogen and pH were higher in the frozen layer than in the active layer but no significant difference was found in the exchangeable magnesium, potassium, and sodium of the two layers. The high concentration of Ca in the frozen layer is likely due both to the transfer of soil moisture and nutrients along the thermal gradient and, as has been found previously, to the high selectivity of organic soils for calcium over magnesium and monovalent cations.

FORMATION NAMES IN THE MACKENZIE RIVER VALLEY

Science ◽  
1936 ◽  
Vol 83 (2140) ◽  
pp. 14-15
Author(s):  
E. M. Kindle
Keyword(s):  
River Valley ◽  
Mackenzie River

scholarly journals Effects of freezing on soil temperature, freezing front propagation and moisture redistribution in peat: laboratory investigations

2012 ◽  
Vol 16 (2) ◽  
pp. 501-515 ◽  
Author(s):  
R. M. Nagare ◽  
R. A. Schincariol ◽  
W. L. Quinton ◽  
M. Hayashi
Keyword(s):  
Water Content ◽  
Active Layer ◽  
Water Movement ◽  
Peat Soil ◽  
Soil Column ◽  
Initial Period ◽  
Soil Freezing ◽  
Permafrost Soil ◽  
Freezing Front ◽  
Discontinuous Permafrost

Abstract. There are not many studies that report water movement in freezing peat. Soil column studies under controlled laboratory settings can help isolate and understand the effects of different factors controlling freezing of the active layer in organic covered permafrost terrain. In this study, four peat Mesocosms were subjected to temperature gradients by bringing the Mesocosm tops in contact with sub-zero air temperature while maintaining a continuously frozen layer at the bottom (proxy permafrost). Soil water movement towards the freezing front (from warmer to colder regions) was inferred from soil freezing curves, liquid water content time series and from the total water content of frozen core samples collected at the end of freezing cycle. A substantial amount of water, enough to raise the upper surface of frozen saturated soil within 15 cm of the soil surface at the end of freezing period appeared to have moved upwards during freezing. Diffusion under moisture gradients and effects of temperature on soil matric potential, at least in the initial period, appear to drive such movement as seen from analysis of freezing curves. Freezing front (separation front between soil zones containing and free of ice) propagation is controlled by latent heat for a long time during freezing. A simple conceptual model describing freezing of an organic active layer initially resembling a variable moisture landscape is proposed based upon the results of this study. The results of this study will help in understanding, and ultimately forecasting, the hydrologic response of wetland-dominated terrain underlain by discontinuous permafrost.

scholarly journals Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 457 ◽  
Author(s):  
F. Hrbáček ◽  
M. Oliva ◽  
K. Laska ◽  
J. Ruiz-Fernández ◽  
M. A. De Pablo ◽  
...  
Keyword(s):  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Active Layer Thickness ◽  
Mean Annual Temperature ◽  
Climate Trends ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
The Antarctic

Permafrost controls geomorphic processes in ice-free areas of the Antarctic Peninsula (AP) region. Future climate trends will promote significant changes of the active layer regime and permafrost distribution, and therefore a better characterization of present-day state is needed. With this purpose, this research focuses on Ulu Peninsula (James Ross Island) and Byers Peninsula (Livingston Island), located in the area of continuous and discontinuous permafrost in the eastern and western sides of the AP, respectively. Air and ground temperatures in as low as 80 cm below surface of the ground were monitored between January and December 2014. There is a high correlation between air temperatures on both sites (r=0.74). The mean annual temperature in Ulu Peninsula was -7.9 ºC, while in Byers Peninsula was -2.6 ºC. The lower air temperatures in Ulu Peninsula are also reflected in ground temperatures, which were between 4.9 (5 cm) and 5.9 ºC (75/80 cm) lower. The maximum active layer thickness observed during the study period was 52 cm in Ulu Peninsula and 85 cm in Byers Peninsula. Besides climate, soil characteristics, topography and snow cover are the main factors controlling the ground thermal regime in both areas.

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