Salt weathering

One of the most interesting developments in desert geomorphology in recent years has been the rediscovery of the role of salt as a weathering agent. Salt weathering is a process of rock disintegration by salts that have accumulated at and near the rock surface. It is the dominant weathering process in deserts especially in coastal and playa areas where saline groundwater may be close to the surface. The significance of surface salts as a cause of rock breakdown in drylands has only recently become fully appreciated with the result that many geomorphological features of drylands such as rock splitting, granular disintegration, and the creation of rock overhangs are often being reinterpreted as the product of salt attack rather than of the traditionally advocated processes of ’wetting and drying’ weathering, insolation weathering and aeolian processes (Cooke et al., 1982). The full significance of salt weathering attack as an engineering hazard has only become apparent recently during the construction boom of the 1970s and post-1980 period in many drylands, such as in the middle east. Here the use of concrete and natural stone for buildings, structures and roads in the presence of salts has resulted in numerous problems ranging from unsightly blemishes to serious failures which in some cases have required costly remedial works. The purpose of this account is to bring together into one review the wide-ranging and disparate studies on salt weathering that have been published in recent years.