Lower Devonian lithostratigraphy of Belgium

The revision of the lithostratigraphic scale of southern Belgium, based on the revised Geological Map of Wallonia and recent stratigraphic and sedimentological works lead to the re-definition of 75 lithostratigraphic units for the Lower Devonian Series. Most of the units described in the present paper are classical subdivisions of the lithostratigraphic scale but updates on their definition, boundaries and age are provided here. New terms are introduced for remarkable beds and facies. Groups are introduced to gather formations than are rarely separated on geological maps whereas some units previously described as formations are here retrograded to members. The dominant lithologies of the Lower Devonian of Belgium reflect siliciclastic sedimentation in various depositional settings ranging from fluviatile conglomerate to estuarine and deltaic sandstone, tidal siltstone and distal delta-front shale on the southern margin of the London–Brabant Massif and around other Caledonian inliers (e.g. Rocroi, Stavelot–Venn). The vertical succession and lateral correlation of the lithostratigraphic units allow to reconstruct the evolution of the shallow basin from the latest Silurian (Pridoli) to the latest Emsian.