Emile Roche

First Clarkforkian equivalent Land Mammal Age in the latest Paleocene basal Sparnacian facies of Europe: fauna, flora, paleoenvironment and (bio)stratigraphy.

The Paleocene-Eocene Thermal Maximum (PETM) is correlated with the first occurrences of earliest modern mammals in the Northern Hemisphere. The latest Paleocene Clarkforkian North American Land Mammal Age, that has yielded rodents and carnivorans, is the only exception to this rule. However, until now no pre-PETM localities have yielded modern mammals in Europe or Asia. We report the first Clarkforkian equivalent Land Mammal Age in the latest Paleocene deposits of the basal Sparnacian facies at Rivecourt, in the north-central part of the Paris Basin. The new terrestrial vertebrate and macroflora assemblages are analyzed through a multidisciplinary study including sedimentologic, stratigraphic, isotopic, and palynological aspects in order to reconstruct the paleoenvironment and to evaluate biochronologic and paleogeographic implications. The mammals are moderately diverse and not abundant, contrary to turtles and champsosaurs. The macroflora is exceptional in preservation and diversity with numerous angiosperms represented by flowers, fruits, seeds and wood preserved as lignite material, revealing an abundance of Arecaceae, Betulaceae, Icacinaceae, Menispermaceae, Vitaceae and probably Cornaceae. Results indicate a Late Paleocene age based on carbon isotope data, palynology and vertebrate occurrences such as the choristoderan Champsosaurus, the arctocyonid Arctocyon, and the plesiadapid Plesiadapis tricuspidens. However, several mammal species compare better with the earliest Eocene. Among these, the particular louisinid Teilhardimys musculus, also recorded from the latest Paleocene of the Spanish Pyrenees, suggests a younger age than the typical MP6 reference level. Nevertheless, the most important aspect of the Rivecourt fauna is the presence of dental remains of a rodent and a “miacid” carnivoran, attesting to the presence of two modern mammalian orders in the latest Paleocene of Europe. Interestingly, these two groups are also the only modern groups recorded from the latest Paleocene of North America, making Rivecourt the first direct equivalent to the Clarkforkian Land Mammal Age outside of North America.

New Integrated High-Resolution Dinoflagellate Cyst Stratigraphy and Litho- and Chemostratigraphy from the Paris and Dieppe-Hampshire Basins for the ''Sparnacian''

The Paris Basin represents an historical cradle of Palaeogene stratigraphy, where during the nineteenth century the Palaeocene Series and the “Sparnacian Stage” were established. As highlighted by Aubry et al. (2005), whereas the chronostratigraphic connotation of the “Sparnacian Stage” has been controversial since its definition, modern studies of the late Palaeocene–early Eocene interval have revealed that the so-called “Sparnacian” deposits encompass a remarkable and short (~170 kyr) episode of the Cenozoic, the Palaeocene–Eocene Thermal Maximum (PETM, ~55.8–55.6 Ma). Dinoflagellate assemblages from the “Sparnacian” of the Dieppe–Hampshire and Paris basins do not contain the key species Apectodinium augustum, whereas it is present in the northern Belgian Basin Tienen Formation and is coeval there with the CIE and the Apectodinium acme interval. However, our calibration of the Apectodinium acme to the CIE in the Dieppe–Hampshire and Paris basins suggests its attribution to the A. augustum zone. The absence of species A. augustum in the Anglo–Paris Basin may be explained by its restriction to more offshore conditions.