Facies analysis and environmental reconstruction of the Upper Cretaceous Chalk Formation in South Limburg, the Netherlands

Abstract

The Late Cretaceous sediments in the Dutch part of the Campine Basin (South-Limburg, the Netherlands) show a great variation in lithology. Since the 1800s, subdivisions of the sediments have been created based on lithostratigraphy, biostratigraphy and chronostratigraphy. In order to understand the depositional environment, these classifications are not sufficient and a facies model is necessary. In this study a facies analysis is presented based on the lithostratigraphic subdivision of Felder (1975) which is matched with an existing biostratigraphic subdivision based on benthic foraminifera. By creating a database for individual members of all outcrops and boreholes in the study area, a dense network of data points can be visualized showing the distribution of lithology per individual member. From this a facies model per individual member is created, showing its distribution and thickness variation, combined with literature data of its age and fossil content. An interpretation of the depositional environment is then created per unit. The facies analysis shows that there is a discrepancy in depocenter for the older Santonian to Campanian sediments compared with the Maastrichtian biodetrital carbonates. It also appeared that the different formations are partly the coeval equivalent of each other. This is the case for the sediments called the ‘Zandig Krijt van Benzenrade’ and the lower part of the Gulpen Formation, as well for the upper part of the Gulpen Formation and lower part of the Maastricht Formation. The facies analysis also gives detailed insights of the tectonics of different structural elements that have influenced these marine shelf deposits of South-Limburg.