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These conditions are considered unusual, [6] restricting it to a process of importance within a few centimeters of a rock's surface and on larger existing water-filled joints in a process called ice wedging. Not all volumetric expansion is caused by the pressure of the freezing water; it can be caused by stresses in water that remains unfrozen.
Frost weathering is the collective name for those forms of physical weathering that are caused by the formation of ice within rock outcrops. It was long believed that the most important of these is frost wedging, which is the widening of cracks or joints in rocks resulting from the expansion of porewater when it freezes. A growing body of ...
Mass wasting is a general term for any process of erosion that is driven by gravity and in which the transported soil and rock is not entrained in a moving medium, such as water, wind, or ice. [2] The presence of water usually aids mass wasting, but the water is not abundant enough to be regarded as a transporting medium.
Plucking is increased where there are preexisting fractures in a rock bed. As the glacier slides down a mountain, energy from friction, pressure or geothermal heat causes glacial meltwater to infiltrate the spaces between rocks. [4] This process, known as frost wedging, puts stress on
Studies between 1990 and present have demonstrated that rock fracture by ice segregation (i.e., the fracture of intact rock by ice lenses that grow by drawing water from their surroundings during periods of sustained subfreezing temperatures) is a more effective weathering process than the freeze-thaw process which older texts proposed. [1]
Ice jacking is a continuous process that occurs during the winter in areas near lakes. The process starts when the ice begins to crack. When water then fills in those gaps, the process repeats and continues until there is a wall of ice surrounding the lake's shoreline, sometimes reaching up to three feet.
As this process continues over many years ice wedges can grow, up to the size of a swimming pool. [ citation needed ] Ice wedges usually appear in a polygonal pattern known as ice wedge polygons . The cracks can also be filled with materials other than ice, especially sand, and are then called sand wedges .
[9] [10] In 1935, Melik discovered that frost weathering had been a very successful geomorphic process in non-glaciated regions of the Slovenian Alps throughout the Pleistocene. The word "periglacial" was not well-known at the time so he merely emphasized enhanced transit of scree down the slopes in relation to mass movement processes.