Cambrian - Ordovician - Silurian lithostratigraphic units (Belgium)

Abstract

The National Subcommission on the Stratigraphy of the Lower Palaeozoic of Belgium has evaluated the previous and present definitions of the Cambrian, Ordovician and Silurian lithostratigraphical units (groups, formations and members) and presents in this paper the results of this evaluation. Some of these units described in published or unpublished documents are considered to be junior synonyms of previously described units. Other units were given a higher or lower ranking. Units that are too thin or too thick were abandoned. The Subcommission reached agreement on the validity and usefulness of all the units that are described below. For each of them, a lithological and sedimentological description is given, the area of distribution and possible facies changes, the thickness of the unit, the arguments for the age determination, some remarks about the history of the definitions, and the names of units considered to be junior synonyms. In the Brabant Massif 32 formations are (re) defined and described, in the Condroz inlier 18 formations, in the Stavelot Massif 3 groups, 8 formations and 8 members, with an additional formation with an unspecified Mid Ordovician-earliest Devonian age, in the Rocroi Massif 3 groups, 7 formations and 2 members, in the Givonne Inlier 4 formations and in the Serpont Inlier 2 formations. The formations are shown in chronostratigraphical tables with a colour encoding the dominant lithology or sedimentology.