To browse Academia. Its top is defi ned by the base of the Livian Substage and coincides with a major bentonite, the 'Banc d'or de Bachant'. It correlates with the late Chadian to Arundian of the British Isles and it provides a record of the fi nal stage of the evolution of the Namur-Dinant Basin from a homoclinal ramp in the Tournaisian to a broad shelf of regional extend end of the Moliniacian. It is characterized by varied facies refl ecting diff erent sedimentary environments across the basin and rich foraminifer and coral faunas that allow good biostratigraphic correlation.
It is known from numerous sections in Belgium and Northern France. The uppermost Famennian Strunian is typically a mixed carbonate-siliciclastic unit that deposited during the transgressive phase of the first 3 rd order sequence. The Devonian-Carboniferous boundary, recognised at the top of the Hangenberg Sandstone event occured during the transgression.
Sequence 3, 4A and 4B are recorded in different units depending on the position on the shelf, notably in the Waulsortian mudmound complex in the southern Dinant sedimentation area and as mostly crinoidal and oolitic limestones in the Condroz sedimentation area.
In more proximal areas, these sequences are often dolomitic and only the highstand system tracts are recorded. Biodiversity hotspots are defined as areas of unusually high biological diversity. This definition is less clear for palaeohotspots but the Royseux locality in Southern Belgium is interpreted as such a site because of the large number of coral species that co-occur within a small area and short time interval.
Forty-one species 29 genera of rugose, tabulate and heterocorallia corals are known within a 6 m-thick 4 th order parasequence kyr. These numbers increase to 50 species in 30 genera if the entire succession is considered.
