Print Email Facebook Twitter The implications of K-Ar glauconite dating of the Diest Formation on the paleogeography of the Upper Miocene in Belgium Title The implications of K-Ar glauconite dating of the Diest Formation on the paleogeography of the Upper Miocene in Belgium Author Vandenberghe, N. Harris, W.B. Wampler, J.M. Houthuys, R. Louwye, S. Adriaens, R. Vos, K. Lanckacker, T. Matthijs, J. Deckers, J. Verhaegen, J. Laga, P. Westerhoff, W.E. Munsterman, D.K. Publication year 2014 Abstract The glauconite-rich Diest Formation in central and north Belgium contains sands in the Campine subsurface and the hilly Hageland area that can be distinguished from each other. The Hageland Diest Sands member contains no stratigraphically relevant fossils while in the Campine subsurface dinoflagellate cysts are common and show a stratigraphic range covering the entire Tortonian stage. K-Ar dates were determined for glauconite from 13 selected samples spread over both areas. A glauconite date corresponding to the earliest Tortonian indicates newly formed glauconite was incorporated into a greensand at the base of the Diest Formation in the central Campine area. All other dates point at reworked glauconite and can be organized in two groups, one reflecting a Burdigalian age and another reflecting a Langhian age. These data and the thickness and glauconite content of the Diest Formation imply massive reworking of older Miocene deposits. The paleogeographic implications of these data lead to the tentative recognition of two Tortonian sedimentary sequences. An older one corresponding to dinoflagellate biochron DN8 comprises the Deurne Member, part of the Dessel Member, the Hageland Diest member, the eastern Campine Diest member and some basal sands of the Diest Formation in the central Campine. A younger sequence corresponding to dinoflagellate biochrons DN9 and 10 was strongly influenced by the prograding proto-Rhine delta front in the Roer Valley Graben to the northeast. The subsiding Campine basin was filled from east to west during this second cycle. Subject Earth / EnvironmentalGM - Geomodelling SGE - Sustainable Geo EnergyELSS - Earth, Life and Social SciencesGeological Survey NetherlandsGeosciencesEnergy / Geological Survey NetherlandsGlauconite reworkingTortonianCampineHagelandPaleogeography To reference this document use: http://resolver.tudelft.nl/uuid:d64cf8fb-1e8b-4f0f-b563-506e48ec3305 TNO identifier 492373 Source Geologica Belgica, 17 (2), 161-174 Document type article Files To receive the publication files, please send an e-mail request to TNO Library.