Résumé
Le tracé de cartes structurales en isohypses, grâce aux prélèvements datés par la microfaune dans le Crétacé et à partir des contours géologiques pour le toit de la Craie et le Tertiaire, permet d'analyser la discordance entre la Craie et les dépôts paléocènes. Les déformations de la Craie apparaissent liées à des efforts en cisaillement contemporains de la phase de compression sub-méridienne fini-crétacée à éocène. La structuration de la Craie acquise avant le recouvre-ment thanétien peut être prépondérante par rapport à celle qui lui est postérieure et de style différent.
Abstract
Isobath structural maps were drawn to show the unconformity between cretaceous chalk and paleocene deposits in western Champagne. Numerous micropaleontological datas in Chalk were used, as well as geological outlines of die erosional Chalk surface and of the Ypresian top-wall. Folding and faulting of the Chalk are bound to shear stresses contemporaneous with the terminal Cretaceous to Eocène submeridian compressional event. Chalk déformations recorded before the thanetian deposits may be locally more important than the younger one, and are possibly of a différent structural settingIsobath structural maps were drawn to show the unconformity between cretaceous chalk and paleocene deposits in western Champagne. Numerous micropaleontological datas in Chalk were used, as well as geological outlines of die erosional Chalk surface and of the Ypresian top-wall. Folding and faulting of the Chalk are bound to shear stresses contemporaneous with the terminal Cretaceous to Eocène submeridian compressional event. Chalk déformations recorded before the thanetian deposits may be locally more important than the younger one, and are possibly of a différent structural setting.
Dernière mise à jour le 31.07.2015