Ice as an Agent of Rock Weathering: A Discussion

Grawe, Oliver R.

doi:10.1086/624415

Cited by 20 publications

(12 citation statements)

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“…Mientras que si la llegada de la nieve sigue su ritmo normal, el número de oscilaciones es 0 (Tabla 31). La tradicional hipótesis de la eficacia de la helada en las áreas pronivales en la primavera, justo después del inicio de la fusión de la nieve, considerada de forma continuada (Matthes, 1900;Hobbs, 1910;Grawe, 1936;Lewis, 1936Lewis, , 1939McCabe, 1939;Gardener, 1969;Thorn, 1976Thorn, , 1979Thorn, , 1988Hall 1980Hall , 1985Hall , 1993Thorn y Hall, 1980, 2002, Goodrich, 1982Nyberg, 1991;Razcokowska, 1995;Christiansen, 1996Christiansen, , 1998Kariya, 2002;Hall et al, 2002) como el principal agente que genera las habituales coladas de solifluxión pronivales, no se puede aplicar a la Sierra de Guadarrama.…”

Section: Discussionunclassified

“…Hobbs (1910) recoge esta idea, y propone que esa capacidad erosiva de los neveros se basa en la abundancia de agua de deshielo circulando bajo la nieve y la proximidad de la temperatura de la superficie de la base del nevero a los 0°C durante gran parte del año, lo que indudablemente facilitaría un alto número de ciclos de hielo/deshielo, con respecto a las áreas fuera del nevero. Grawe (1936) inicia la monitorización de las temperaturas para comprobar esa eficacia. Pero no es hasta mucho después, cuando la monitorización térmica del suelo en áreas nivales se generaliza, con trabajos pioneros y claves, como los de Gardener (1969), Thorn (1976Thorn ( y 1979, Hall (1980) y Thorn y Hall (1980).…”

Section: Introductionunclassified

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Cobertura nival y distribución de las temperaturas en el suelo en las cumbres de la Sierra de Guadarrama

Pablo

Estremera

2013

CIG

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Section: Discussionunclassified

Section: Introductionunclassified

Cobertura nival y distribución de las temperaturas en el suelo en las cumbres de la Sierra de Guadarrama

Pablo

Estremera

2013

CIG

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“…These targets were also categorized into central targets (numbered 4), the inner targets (numbered 3,7,12,14), the outer targets (numbered 2, 6, 9, 12), and marginal targets (numbered 1, 7,8,13). The annual average upfreezing heights of these four groups of targets are 4.9, 5.4, 5.3, and 6.3 cm respectively.…”

Section: Effects Of Upfreezing With Different Positions In Sorted Circlementioning

confidence: 99%

“…This kind of hypothesis is called frost-pull. Grawe [8] contend that upfreezing is explained by the greater heat conductivity of objects than fines, whereby ice forms around objects or at their base and forces them up. They suggest that the seeping in of fines during thawing would prevent objects from returning to their original position.…”

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confidence: 99%

Global warming accelerates the upfreezing of permafrost in arid middle Tianshan Mountains

Chen

Nie

et al. 2013

Chin. Sci. Bull.

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Upfreezing is an important geomorphic process in the periglacial environment. It is a product of cold climate and thus an important part of the cryospheric processes. Based on the long-term positioning observations in the source area of the Urumqi River, this article represents an in-depth discussion of the characteristics of sorted circles and upfreezing mechanisms in the Tianshan Mountains. In the source area of the Urumqi River, the intensity of upfreezing is the highest within the top 25 cm near the surface, while targets with a diameter of 3 cm are least affected by upfreezing. There is no distinct difference between the centre with fine grains and the margin with coarse debris within the same sorted circle in terms of the intensity of upfreezing. The correlation analysis demonstrates that temperature plays an important role in upfreezing and the development of sorted circles. A long-time positioning observation of sorted circles reveals that periglacial landforms are sensitive to regional climate change and respond quickly to the temperature increase of the recent two decades. Enhanced upfreezing was found to be due to increased soil moisture content.

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“…Maximum pressures of 214 MPa at -22°C far exceed the tensile strength of even the most resistant rocks (RZHEVSKY and NOVIK, 1971 ;WINKLER, 1973). These pressures, however, are probably unobtainable in the field (GRAWE, 1936). Although many types of rock are severely damaged by their exposure to temperature fluctuations about the freezing point, the responsible mechanisms are still the subject of considerable debate.…”

Section: The Mechanismsmentioning

confidence: 99%

Freeze-thaw and shore platform development in Gaspé, Québec

Trenhaile

Rudakas

2011

gpq

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The role of freeze-thaw action in coastal environments, with particular reference to the formation of sub-horizontal shore platforms in Gaspé, Québec, was investigated experimentally. Rock cores and crushed rock samples were subjected to: two freeze-thaw cycles of twelve and twenty-four hour durations; fresh water and three artificial sea water solutions of about half, one and a half, and 'normal' salinity; and two drainage conditions representing rock pools and vertical well drained surfaces. These variables were selected to simulate some of the local environments which exist between the cliff top and low tide level in coastal Gaspé. Shales were the most susceptible to frost breakdown, followed in turn by argillites, calcisiltites and dolomitic silty argillites, and graywackes. Greatest disintegration tended to be associated with sea water solutions of about half-normal salinity. The data suggest that breakdown is greatest in the lower portions of the cliff. Freeze-thaw may produce the moat-like pools commonly found at the back of shore platforms. Although the process undoubtedly facilitates wave erosion of the platform and cliff, however, there is no evidence to suggest that it causes shore platforms to assume subhorizontal gradients.Le rôle de la gélifraction en milieu littoral, en particulier dans la formation des plates-formes subhorizontales en Gaspésie, a été étudié d’une façon expérimentale. Des carottes et des fragments de roc ont été soumis à des cycles gel-dégel de 12 et de 24 heures, les uns dans de l’eau ordinaire et les autres dans de l’eau de mer à salinité normale, à demi-salinité et à salinité et demie, dans des conditions d’humidité correspondant à celles des cuvettes rocheuses et des escarpements verticaux. Les conditions furent déterminées en regard des milieux naturels locaux prévalant dans la zone comprise entre le haut de la falaise et le niveau des basses mers, sur la côte nord de la Gaspésie. Les schistes se sont révélés les plus sensibles à la gélifraction; viennent ensuite dans l’ordre de plus grande sensibilité, les argilites, les calcshistes, les argilites dolomitiques et les grauwackes. La gélifraction maximale s’est produite dans une solution correspondant à la demi-salinité de l’eau de mer. Les résultats indiquent que la gélifraction est plus importante dans la partie inférieure de la falaise. Elle pourrait être à l’origine des cuvettes superficielles entaillant les plates-formes littorales. Bien que la gélifraction soit un processus favorisant l’érosion par les vagues des plates-formes et des falaises, rien ne permet d’affirmer qu’elle soit à l’origine des plates-formes littorales subhorizontales en Gaspé.Die Rolle der Gelifraktion in Kustengegenden, mit besonderem Hinweis auf die Entstehung von subhorizontalen Küstenplattformen in Gaspé, Québec, wurde im Experiment untersucht. Bohrungskerne und zermahlene Gesteinsproben wurden folgenden Kräften aus-gesetzt: zwei Gefrierund Auftauzyklen von zwölf und vierundzwanzig Stunden Dauer, Frischwasser, und drei künstliche Salzwasserlösunge...

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Ice as an Agent of Rock Weathering: A Discussion

Cited by 20 publications

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Cobertura nival y distribución de las temperaturas en el suelo en las cumbres de la Sierra de Guadarrama

Cobertura nival y distribución de las temperaturas en el suelo en las cumbres de la Sierra de Guadarrama

Global warming accelerates the upfreezing of permafrost in arid middle Tianshan Mountains

Freeze-thaw and shore platform development in Gaspé, Québec

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