Middle 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, has led to the re-definition of 63 lithostratigraphic units for the Middle Devonian Series. Although most of the units described in the present overview are classical subdivisions of the Belgian lithostratigraphic scale, updates on their definition, boundaries and age were required and are provided herein. New terms are introduced for remarkable beds and facies. Groups are introduced to gather formations that are difficult to separate on geological maps, whereas some previously described formations are here retrograded to member status. The Middle Devonian units recorded the development of the carbonate factory in the Eifelian, interrupted by siliciclastic deposits followed by the development of a wide carbonate shelf during the Givetian. Reefs occur both in the Eifelian (offshore bioherms, biostromes on platforms) and in the Givetian (biostromes). The vertical succession and lateral correlation of the lithostratigraphic units allow to reconstruct the evolution of the shelf from the early Eifelian to the demise of the carbonate shelf at the end of the Givetian.