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 0°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.