摘要:

The origin of massive bodies of ground ice in Western Siberia is reconsidered on the basis of new publications and of the authors’ field observations at the Ledyanaya Gora site. The available evidence suggests that the largest ice bodies are of glacier origin and are buried remnants of the Kara Ice Sheet. The influence of permafrost accounts for their preservation. The volume of ground ice contained in these ice bodies amounts to about 10,000 km3, which is 67% of the total volume of present‐day glaciers in the USSR. This type of ground ice ought to be the subject of special glaciological studies. Similar remnants of former ice sheets preserved in permafrost have been discovered in the north of Central Siberia, Alaska, and Canada. All these regions also contain ground ice bodies of segregation, injection, and wedge origin. The occurrence of ground ice and especially of massive, tabular ice bodies creates a range of growing environmental problems with regard to economic development in Western Siberia. The destruction of vegetation and soils in association with this development leads to changes in geo‐thermal conditions at the earth's surface which in turn cause instantaneous degradation of natural landscapes. Possible measures for protecting the cryogenic landscape are briefly discussed.

ISSN:0273-8457    

DOI:10.1080/10889378609377286

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

On the basis of available information on snow depths, atmospheric temperature, vegetation cover, types of sediment and ice content of sediments to a depth of 10 m the authors have developed maps of northern areas of Western Siberia which illustrate the probability of provocation of technogenic thermokarst as a result of a) increase in snow depth and b) removal of the vegetation cover. The maps allow one to estimate the permissible increase in snow depth in the case of a) removal and b) preservation of the vegetation cover, the probability of the development of thermokarst with removal of the vegetation cover and possible settlement of the ground if the sediments thaw. In general terms four zones can be delimited in terms of potential for thermokarst development with removal of the vegetation cover. In the northernmost zone (Zone I) removal of vegetation will not lead to thermokarst development in any type of natural microregion, even in areas of deep snow accumulation. In Zone II, farther south, removal of the vegetation will produce thermokarst only in areas of high snow accumulation. In Zone III, farther south again, removal of the vegetation will provoke thermokarst in areas of moderate snow accumulation but not in areas with low snow depths. And finally, in Zone IV, the most southerly of all, removal of the vegetation will produce thermokarst in all areas of permafrost occurrence (in this area, almost exclusively in peat bogs).

ISSN:0273-8457    

DOI:10.1080/10889378609377287

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The article changes in geocryological conditions resulting from the destruction of various vegetation associations on terraces of the Lena River about the town of Pokrovsk, and from restoration of the vegetation cover. It was found that with removal of a larch forest the active layer depth increased by 40–50% and moisture content of the sediments decreased by 25%, whereas with removal of a pine forest the active layer depth increased by only 10% and the moisture content of the sediments effectively remained unchanged. With recolonization by vegetation it was found that the re‐establishment of the geocryological conditions and especially the return to the original active layer depth, occurred much more rapidly than re‐establishment of the original natural vegetation association.

ISSN:0273-8457    

DOI:10.1080/10889378609377288

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The Schirmacher Oasis is a small, ice‐free area, some 18 km by 1.8 km, located in Dronning Maud Land and lying between the Lazarev Ice Shelf to the north and the Antarctic Ice Cap to the south. The climate is quite variable with a mean annual air temperature of ‐10°C, a mean temperature of ‐18.1°C for the coldest month and ‐0.7°C for the warmest month. Annual precipitation is approximately 300 mm. The entire area is underlain by permafrost. Active layer depths range between 80 cm in dry, fine‐grained materials and 7 cm in areas of ice‐rich algal accumulations. The author investigated in detail the depth of the active layer in a stony polygon. In unconsolidated materials the commonest variant of cryogenic structure is a massive subtype with no lenses or layers of ice; a streaky subtype occurs in some fine‐grained sediments. Segregation ice is relatively rare and no wedge ice was reported. The only massive ground ice is buried glacier ice near the ice cap margin. Frost shattering is the most widespread and most effective weathering mechanism. Sorted circles, nets and polygons are widespread in the unconsolidated materials and were studied in detail by the author. Sorted stripes occur only rarely. Thermokarst is very poorly developed even where blocks of buried ice were exposed.

ISSN:0273-8457    

DOI:10.1080/10889378609377289

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The article compares the area of the Antarctic ice shelves as presented on earlier maps (1961 and 1964) with that based on the latest available data (1984). The results indicate that despite catastrophic calvings such as those from the Amery, West, Bellingshausen, and Thwaites ice shelves, involving a total of about 20,000 km2of ice, the total area of the Antarctic ice shelves during this 20‐year period increased by 135,000 km2or by 9 percent. This expansion is largely the product of improvements in plotting the boundaries of the ice shelves, especially their inner boundaries. The latest estimate of the total area of the continent, including ice shelves and islands attached by ice shelves, is 13,980 million km2.

ISSN:0273-8457    

DOI:10.1080/10889378609377290

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The Bellingshausen Ice Shelf was a prominent lobe‐shaped tongue which projected from the coast of Antarctica on the Greenwich Meridian. First charted in 1938–39, it was still about the same size in 1949–52, reaching about 69°25 ‘S. But by 1955 it had expanded enormously, reaching a latitude of approximately 69°S; its area north of the 70th parallel was about 5000 km2. A survey made from the Soviet research vesselEvrikain March 1981 revealed that the ice shelf had shrunk drastically, its boundary retreating south to about 69°40 ‘S. The northern boundary was observed to be approximately still in the same position during a visit by the Soviet vesselVol'nyy veterin January 1983.

ISSN:0273-8457    

DOI:10.1080/10889378609377291

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The article sets forth some novel approaches to the development of new mining regions especially in the East and North of the USSR. The point at issue is the accelerated rates of development of these areas and the establishment of a productive and social infrastructure and of service and auxiliary sectors as well as the widening of the structure of the economy on the basis of new technology. This raises the question of how to ensure a denser and more stable population. The author substantiates the effectiveness of a special normative base. He also stresses the need for new methodological ecological/economic approaches. In short an attempt is made to develop a new type of economic thinking with regard to developing uninhabited areas.

ISSN:0273-8457    

DOI:10.1080/10889378609377292

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0273-8457    

DOI:10.1080/10889378609377293

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0273-8457    

DOI:10.1080/10889378609377285

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor