Problems of lithostratigraphic classification of Holocene deposits in the perimarine area of The Netherlands

Abstract

Lithostratigraphic mapping always faces the problem of to what detail separate units should be distinguished. It is quite clear, for instance, that a rough first mapping requires other standards than a highly specialized investigation. Consequently, the choice of lithostratigraphic units should be based on flexible criteria (cf. Hedberg 1976).In practice the rules applied seem to be strongly influenced by national and historical developments. In the USA, for instance, hard-rock formations tend to be several hundreds of metres thick; in The Netherlands, in contrast, the Quaternary succession has been subdivided in formations and members which often have a local or even regional thickness of less than one metre. Berendsen (1984b), in an elegant analytical paper, recently argued that the detailed 'lithostratigraphic' subdivision of (sub)recent deposits in The Netherlands, as applied by the Dutch Geological Survey, gives rise to serious problems since various concepts are mixed and used simultaneously in an unacceptable way. In fact, he underlined rather similar views published earlier in a special issue of this journal on Quaternary geology (Van Loon 1981). A main problem is the term 'Westland Formation', formally introduced by Doppert et al. (1975) in an explanation to the new geological maps (Zagwijn & Van Staalduinen 1975). Berendsen (1984b) once more demonstrate that both the theoretical definition and the practical mapping of the Westland Formation are based on illogical concepts.