Pleistocene Climatic Significance of Calcretes and Ferricretes

Abstract

CALCRETES and ferricretes are widespread features of African soils. They have attracted attention from both soil specialists and archæologists, for they frequently occur in soil profiles containing Stone Age artefacts and fossils. The calcretes and ferricretes have been generally assumed to have climatic and stratigraphic significance. Archæologists and geologists have dated them in terms of associated artefacts or fossils, just as other geological horizons are dated by in situ cultural or organic objects. R. F. Flint¹ has summarized recent views on the climatic interpretation of ferricretes and calcretes. Flint suggests that ferricrete formation requires rainfall ‘above a certain minimum’, stating that ferricretes “seem to indicate Pleistocene climates that were wetter than those of to-day, provided Pleistocene age is established”, while calcretes imply low rainfall, perhaps less than 18 in. (45.6 cm.) per annum.