Weathering of sandstone by the combined action of frost and salt

Abstract

Preliminary results from a continuing series of laboratory experiments designed to examine the combined effects of salt and frost weathering indicate that some salts greatly enhance the breakdown of rocks by frost. Samples of Ardingly Sandstone from southeast England were soaked in saturated solutions of sodium chloride or sodium sulphate and subjected to alternating cycles of freezing and thawing. Rapid disintegration of the sandstone occurred within twenty cycles, in each of the salt solutions. In contrast, samples subjected to freezing and thawing in deionized water suffered very little damage unless they were saturated under vacuum.When samples were subjected to twenty cycles of wetting and drying at temperatures above O' C, those soaked in deionised water or sodium chloride suffered no appreciable damage but those soaked in sodium sulphate rapidly disintegrated.Tentative explanations of these results are offered. The enhancement of frost weathering by salt appears to have been overlooked by many writers yet it is likely to be an important geomorphological process in those areas of mid and high latitudes where rocks are saturated with sodium salts.

Rates and patterns of bedrock denudation by coastal salt spray weathering: A seven‐year record

“…The possibility that salt weathering is enhanced in conjunction with frost has been discussed by previous authors (Williams and Robinson, 1981;McGreevey, 1982;Robinson and Jerwood, 1987a, b). Fahey (1983) has demonstrated that hydration weathering of schist is enhanced by frost.…”

Experimental frost weathering of sandstone by various combinations of salts

“…Williams and Robinson, 1981). It occurs with or without the addition of salts, presumably because the pores are being enlarged slightly by frost action, allowing more solution to be absorbed.…”

“…Experiments by Dunn and Hudec (1966) and Goudie (1974) demonstrated that salts could enhance the frost weathering of calcareous rocks, and Williams and Robinson (1981) showed that frost weathering of sandstone was greatly enhanced by the presence of sodium sulphate or sodium chloride. The range of possible mechanisms by which salts may enhance frost weathering have been discussed by Williams and Robinson (1991).…”

Classification of rock weathering at writing‐on‐stone Provincial Park, Alberta, Canada: A study in applied geomorphology

“…Ice and salt crystal growth can have strongly disruptive effects on weak, fractured rock, and the surfaces and subsurface layers show weathering patterns of the kinds typically associated with frost and salt action on sandstone (Figures 2 and 3). Williams and Robinson ( 1983) found the highly porous Ardingly sandstone readily disintegrated during freeze-thaw cycles following saturation in various salt solutions. Strong variations in weathering reflected differences in grain size with samples having high silt/clay contents being most susceptible.…”