Dayas: Distribution and morphology of dryland solutional depressions developed in limestones

摘要

Dayas, small depressions found on limestone surfaces in drylands, have been revealed by remote sensing to be surprisingly widespread. Examples are known from North Africa, East Africa, Namibia, Kenya, South Africa, the High Plains of the USA, the Pampas of Argentina, the Nullarbor Plain of Australia, and various parts of the Middle East. They display a range of morphologies, but some of them, in the USA, Namibia, Australia and Algeria appear to have been developed as a result of solutional etching into former interdunal depressions. Most are developed on Tertiary limestones or on calcretes.