La Vie en Ardenne occidentale au Paléozoïque supérieur (Dévonien-Carbonifère, -416 à -299 Ma) : paléobiodiversité, événements paléobiologiques, paléoenvironnements, paléobiogéographie

Abstract

The Ardenne Massif is part of a complex of Palaeozoic outcrops between the Channel in the west and the Rhine river and beyond in the east. It has registered both the Caledonian and the hercynian orogenies. Originally part of a terrane located north of the Gondwana supercontinent (Avalonia), it became an element f the southern margin of the Old Red Sandstone Continent (ORSC, also called Euramerica, Laureuropa, or Laurussia) in the Devonian and Carboniferous, when it suffered the effects of the Hercynian orogeny by collision of the ORSC and Gondwana. These global tectonic events, linked to climatic changes due to continental dirft, had profound consequences on the living organisms of the Ardenne Massif. Here we focus on some aspects of a series of animal groups of western Ardenne, being elements of either the benthos (brachiopods, trilobites), or the reefal environments (tabulate corals, stromatopores), or the nekton (vertebrates, including the first tetrapods). When vertebrates ("fishes") and brachiopods were quite abundant as early as the base of the Devonian, mortly in siliciclastic facies, reefal organisms appear only in the Emsian, and become abundant in the Eifelian, with the development of a carbonate platform. Reefs or reef-like buildings occur up to the Early Carboniferous, where new fish assemblages are known. Trilobites occur often with brachiopod-bearing communities. The trilobite-rich locality of the "Mur des Douaniers", at the former French/Belgian boundary, is an example of an early Eifelian Fossil-Lagerstatte, now protected as a Nature Reserve