摘要:

AbstractActive rockglaciers are discussed as the visible expression of creep of alpine or mountain permafrost. They are mainly formed below talus slopes (talus rockglaciers) and below lateral and terminal moraines (debris rockglaciers). Rockglaciers prefer continental, comparatively dry, winter‐cold mountains. They are not well developed in high maritime and humid tropical mountains. Active rockglaciers are indicators of active mountain permafrost and, thus, of great geoecological information valu

ISSN:1045-6740    

DOI:10.1002/ppp.3430030303

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:1045-6740    

DOI:10.1002/ppp.3430030304

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractVertical movements of boulders within a subnival boulder pavement were measured at 2800 m a.s.l. in the Alps over a period of 10 years. It was demonstrated that some boulders are undergoing sinking and others upheaving. The upheaving occurs in autumn during ground freezing, while the sinking of boulders probably occurs in springtime when the ground temperature is below 0 °C under the snow patch

ISSN:1045-6740    

DOI:10.1002/ppp.3430030305

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA survey of painted lines on the top and frontal zone of a talus rock glacier allows one to present a longitudinal profile of the surficial velocity distribution. Measurements were taken over a 8–12 year period at regular intervals and the results now provide information on the variability of displacements. In the upper zone a recent slowing of movement coincides with negative mass balance of local glaciers. Discussion focuses on the variations in velocity of the rock glaciers over the short time‐sc

ISSN:1045-6740    

DOI:10.1002/ppp.3430030306

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractRock glaciers made by talus creep are common landforms in Svalbard. This area has continuous permafrost with thicknesses varying from about 150 m to 500 m. Most rock glaciers are located in coastal areas at altitudes just above sea level, often situated below the escarpment which delimits the inner part of the strandflat. Most rock glaciers are active (at one rock glacier, annual movement rates of 3–10 cm were measured), but inactive rock glaciers with no movement in their frontal parts also exist in many areas. Their stagnation is due to topography and not to climate.In Norway relic rock glaciers are found in coastal areas in the northern part of the country. Together with other relic permafrost features such as tundra polygons and ice‐cored moraines, the distribution of relic rock glaciers indicates that coastal areas in northern Norway had continuous permafrost during the Younger Dryas and earlier phases of the deglaciat

ISSN:1045-6740    

DOI:10.1002/ppp.3430030307

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper describes the vertical zonation of cryogenic forms and their climatic significance in a region of the Central Andes near Mendoza, Argentina.

ISSN:1045-6740    

DOI:10.1002/ppp.3430030308

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractPermafrost and periglacial features occur at high elevations in the mountains of New England (Presidential Range), Gaspésie, Western Newfoundland and Labrador. Both active and inactive patterned ground features have been reported together with block fields and felsenmeer. Problems relate to the complex deglaciation histories of the areas in question, the possibility that nunataks existed during the last glaciation, and the role of cold‐based versus warm‐based ice in landform preservation. There is need for more research on periglacial features and deposits in the alpine zone of eastern North Ame

ISSN:1045-6740    

DOI:10.1002/ppp.3430030309

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractGround temperatures have been measured over a 5 year period of between −1.8 °C and −2.3 °C at 10m depth on a mountain plateau, 1851 m a.s.l. in Jotunheimen, southern Norway (61°40′N, 8°20′E). On the basis of additional shallow ground temperature measurements at different altitudes, the change in ground temperature with altitude is estimated to be 0.57 °C/100 m. This estimate, combined with the measured mean annual ground temperature, indicates the lower limit of discontinuous permafrost in the area to be at 1450–1500 m a.s.l. The mean annual ground temperature above 2200 m a.s.l. is below −4 °C. These values are representative for flat or slightly convex areas. Owing to strong winds, there is little snow until late April at the ground temperature measurement site. Maximum snow dept

ISSN:1045-6740    

DOI:10.1002/ppp.3430030310

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe distribution of permafrost in the Daisetsu Mountains is discussed on the basis of freezing and thawing indices and the pattern of winter snow distribution. Mean annual air temperature at an altitude of 2000 m a.s.l. is estimated to be −3.6 °C in normal years. Alpine permafrost is distributed mainly on windward bare ground. The windward bare ground extends to summit areas, where most snow is removed from the ground surface by strong prevailing wind. The lower limit of permafrost is considered to be about 1650 m a.s.l. Some active periglacial processes, such as palsa formation and frost cracking, are explained by the present climate of the Daisetsu Mountai

ISSN:1045-6740    

DOI:10.1002/ppp.3430030311

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThe near‐surface ground thermal regime at 4720 m a.s.l. is described and assessed in terms of its daily and annual fluctuations (frost cycles, freezing and thawing depths, etc.). Correlation between solar radiation and soil temperature in the uppermost parts of the soil is caused by intense radiation (mean annual value of 22.3 MJ m−2d−1). Surface soil temperatures show an enormous amplitude (>50 °C in a depth of O.1 m) and frost cycles occur almost throughout the year. The seasonally frozen ground extends to only 1.5 m in

ISSN:1045-6740    

DOI:10.1002/ppp.3430030312

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY