Famennian charcoal of Belgium

Charcoal results from an incomplete combustion of biological material in anoxic conditions and has a high potential for three-dimensional cellular preservation. Most of the Belgian Upper Devonian flora is known through compression fossils, mainly from the siliciclastic Evieux Formation; no charcoal-bearing layers had been reported to date. We have recently identified organic-rich beds from three late Famennian localities (Val-Dieu quarry, Trooz quarry and Arbre quarry). The three localities are described from the sedimentological point of view. The Arbre and Trooz quarries contain allochthonous specimens of charcoalified wood. They are identified as Callixylon in Arbre. In Trooz, the specimen belongs either to an undescribed species of Callixylon or to another taxon of woody (pro)gymnosperm. The Val-Dieu quarry, by contrast, yielded a more diverse charcoalified assemblage including leafy remains, branches and fertile axes related to ferns, sphenopsids and (pro)gymnosperms. This material experienced moderate transportation before burial. The Val-Dieu assemblage is exceptional for Late Devonian deposits as it represents a moderately disturbed litter interpreted as representing a swamp environment and its proximal margins. This assemblage is an illustration that the fossil charcoal record can provide a unique opportunity to study in fine detail the evolutionary history and past diversity of life.