Magnetostratigraphy of the Maastrichtian continental record in the Upper Aude Valley (northern Pyrenees, France): Placing age constraints on the succession of dinosaur-bearing sites

• A magnetostratigraphic study is performed in the Aude area (southern France).
• The continental upper Maastrichtian is very reduced or absent in the Aude area.
• A marine regression took place earlier in the northern Pyrenees than in the south.
• A characteristic dinosaur fauna is found in the lower Maastrichtian of SW Europe.

The first detailed stratigraphic succession of the Upper Cretaceous continental record from the Upper Aude Valley (southern France) is presented together with a magnetostratigraphic study. The combined stratigraphy and magnetostratigraphy of the Marnes rouges inférieures Fm (Lower Red Marls), constrained by biochronological markers such as charophyte occurrence and revised dinosaur eggshells, results in a succession of fluvial red beds dated from chron C32n to the top of chron C31r. It implies an earliest Maastrichtian age close to the C32n.1n-C31r reversal for the majority of the dinosaur sites including Bellevue. In contrast, the upper Maastrichtian is likely represented by a short interval within the lacustrine-palustrine Calcaires et argiles de Vignevieille Fm (Vignevieille Limestones), or it might even not be recorded. The proposed age indicates that the marine to continental transition, as a result of the Late Cretaceous transgression, took place earlier in the north Pyrenean basin than in the southern area.