The distribution and form of flint, with particular reference to the Chalk Group (Upper Cretaceous) of the Northern Province, UK

Abstract

Flints are recognized reliable lithostratigraphic markers in chalk sedimentary rocks and may provide an indication of Late Cretaceous palaeogeographic conditions. Their distribution and often characteristic form allow correlation over a wide area, and they may provide information about the local variations in submarine topography and water depth. The absence of flint from parts of the Chalk Group is, like its presence, predictable, but not as well explained. The distribution of flint in the Northern Province is reviewed with quantitative methods being used to highlight sedimentary patterns, flint-rich levels and a possible correlation with marlstones containing reworked volcanic ash. The form of flints is considered to be an expression of conditions prevalent within the chalk sedimentary pile which, in turn, is influenced by variations in sea floor topography and water depth. Therefore, flints may be regarded as indicators of late Cretaceous environmental conditions; their distribution over the area of a wide, generally similar, shelf sea and their form demonstrates subtle local variations in water depth and sediment properties.