Source of brackish ground water in Pleistocene formations beneath the Dutch Polderland

Translation (by J. E. Upson) of an unpublished paper presented at a meeting of the Royal Netherlands Geological and Mining Society in 1950. Data from borings in the Ijsselmeer basin indicate that, in general, the chloride concentration increases gradually with depth in ground waters of the Pleistocene deposits, mainly pre-Riss fluviatile sands, which overlie fine-grained marine Tertiary (and Icenian) sediments. The observed depth/salinity curves can best be explained by postulating an essentially continuous modification of fresh waters by upward diffusion of salt from the marine deposits during the past 500,000 years.