ABSTRACT

In general, Scottish soils are relatively young, being developed mainly upon glacial drift associated with the Devensian period. The mineralogical composition of the tills and solifluction deposits often compares quite closely with that of the directly subjacent or closely associated rocks. This chapter outlines the possible modes of origin of the clay minerals in Scottish soils and provides examples of the clay mineralogy of the main Scottish soil associations. An attempt is then made to synthesise this information so that mineralogical criteria can be developed which may be of general use in the interpretation of the weathering history of Scottish soils. Illustrating the relationship between mineralogy and weathering history in Scottish soils is facilitated by emphasising those associations developed upon a uniform type of parent material with a limited ability for contributing inherited clay, particularly of the kaolinite group. Since the last Devensian glaciation, Scottish soils have generally been subjected to the ‘biochemical’ type of weathering described by Duchaufour.