Origine de l'ambre des faciès sparnaciens (Éocène inférieur) du Bassin de Paris : le bois de l'arbre producteur

Amber is known from several sites of the Paris Basin since the beginning of the 19 th century. All the listed sites date back from the early Eocene and are related to the Sparnacian continental facies. A new deposit recently discovered in the Oise department provided a great amount of this fossil resin. Other macrofossils of plants, especially some wood fragments connected to resin flows were also collected. This particular wood shows parallel horizontal furrows, that are macroscopically visible. Discovered for the first time in 1904 in the Paris subsoil, this wood was partially described by Combes under the name Aulacoxylon sparnacense Combes, 1907. It is described here on the bases of new records from the Oise area. The wood structure of the resin producing tree is very similar to those of the Detarieae tribe of the Caesalpiniaceae fa-mily (angiosperms, eudicotyledons), especially to the modern genus Daniellia Benn. The study of some other components of the paleoflora leads to the reconstitution of the vegetation landscape. A mozaic of gallery-forest was mixed with dryer plant communities, in a deltaic subtropical area. The amber and the wood named Aulacoxylon sparnacense are good markers of this interval and environment. The paleogeographic limits of this environment are obtained from the inventory of the amber sites in the Paris Basin and probably correspond to the limits of the continental facies in this region.