Une nouvelle faune d'Esthéries (Branchiopoda, Conchostraca) dans le Crétacé inférieur du Nord-Est du Brésil

A new Estherian fauna (Branchiopoda, Conchostraca) from the Lower Cretaceous of Northeastern Brazil. A new estherian fauna has been collected in the Northeastern Brazil, in the Souza Basin, state of Paraíba. In a formation with dinosaurian trackways of Lower Cretaceous age, occurred very large carapaces of Asmussia and Palaeolimnadiopsis genera and some small specimens of Graptoestheriella genus. In this assemblage are collected non-cyziciid genera, which are badly known in the Southern America. So the Asmussia genus is pointed out in the Northeastern Brazil, with a new species, Asmussia souzae. The collected conchostracans show affinities with some african forms known in Niger, Cameroun, Zaire. They make possible a best paleogeographical and palaeoecological approach of these non-marine levels within the Lower Cretaceous of the old Gondwanaland.Une nouvelle faune d'Esthéries (Branchiopoda, Conchostraca) dans le Crétacé inférieur du Nord-Est du Brésil. Une nouvelle faune d'Esthéries a été récoltée au Nord-Est du Brésil, dans le bassin de Souza, état de Paraíba. Dans une formation à empreintes de Dinosaures, attribuée au Crétacé inférieur, ont été recueillies des carapaces de très grande taille rapportées aux genres Asmussia et Palaeolimnadiopsis, et quelques petits éléments attribués au genre Graptoestheriella. L'ensemble correspond à des genres non Cyziciides, mal connus en Amérique du Sud. Le genre Asmussia est signalé dans le Nord-Est du Brésil avec une espèce nouvelle, Asmussia souzae. Les Conchostracés recueillis montrent des affinités avec certaines formes africaines décrites au Niger, au Cameroun, au Zaïre, d'où leur intérêt en paléogéographie. Ils permettent une meilleure approche paléoécologique de ces niveaux non marins, connus dans le Crétacé inférieur de l'ancien Gondwana.Una notable fauna de Estherias (Branchiopoda, Conchostraca) en el Cretácico inferior del Noreste del Brasil. Una notable fauna de Estherias fue recogida en el Noreste del Brasil, en la cuenca de Souza, estado de Paraíba. En una formación con huellas de Dinosaurios, atribuida al Cretócico inferior, fueron recogidas conchas de gran tamaño correspondientes a los géneros Asmussia y Palaeolimnadiopsis, y algunos pequeños elementos correspondientes al género Graptoestheriella. El conjunto pertenece a generos no Cyziciides, poco conocidos en America del Sur. El género Asmussia es señalado en el Noreste del Brasil con una nueva especie, Asmussia souzae. Los Conchostraceos recogidos tienen afinidades con cientas formas africanas descritas en Niger, Cameroun, Zaïre, de ahi su interés en paleogeografía. Permiten una mejor comprensión paleoecológica de los niveles no marinos, conocidos en el Cretaceo inferior del antiguo Gondwana.Guérin-Franiatte Simone, Taquet Philippe. Une nouvelle faune d'Esthéries (Branchiopoda, Conchostraca) dans le Crétacé inférieur du Nord-Est du Brésil. In: Documents des Laboratoires de Géologie, Lyon, n°125, 1993. Paléontologie et stratigraphie d’Amérique latine. Table ronde européenne. Lyon, 7-8-9 juillet 1992. pp. 203-221

Cephalopods from the Jurassic "Minette" Ironstone Formation of Luxembourg and Lorraine (NE Paris Basin): past and current research.

VIII International SYMPOSIUM Cephalopods: Prensent and Past, ABSTRACT VOLUME. DiJon (France), 30 agosto-4 settembre 2010, DIJON, vol.

Chronology of the Early Toarcian environmental crisis in the Lorraine Sub-Basin (NE Paris Basin)

Early Toarcian (Jurassic; ~183Ma) sediments recorded profound environmental changes, including mass extinction, global warming, marine transgression as well as widespread bottom water anoxia and organic matter accumulation on the Western Tethyan shelf. Enhanced organic matter accumulation was accompanied by a positive carbon isotope excursion (CIE) in pelagic carbonate, which marks the Toarcian Oceanic Anoxic Event. These environmental changes were accompanied by a major perturbation of the global carbon cycle, expressed by negative CIE, interrupting the positive trend. The duration of the carbon cycle perturbation is still debated, with estimates for the negative CIE range from ~200 to ~600kyr. Here we present ultra high-resolution (<1kyr) measurements of magnetic susceptibility and sediment color from a marine section located in the Lorraine Sub-Basin (NE Paris Basin) documenting Milankovitch-controlled fluctuations in depositional conditions that occurred superimposed onto the overall sea level evolution. Differences in the wavelength of the sedimentary cycles indicate variable sediment accumulation rates that mainly resulted from rapid sea level fluctuations. The most pronounced sea level rise that took place within the uppermost tenuicostatum zoneresulted in a strong condensation of the basal Schistes Carton formation. Strong condensation can explain the discrepancy between durations previously calculated for the CIE placed at this stratigraphic interval. Our data support durations of ~900kyr and ~600kyr for the positive and negative CIE, respectively. The cyclostratigraphy-based timescale further proposes a duration of >555kyr for the tenuicostatum zoneand 1310kyr for the serpentinum zone. The durations of the elegantulumand falciferumsubzonescan be estimated to ~790kyr and ~520kyr, respectively. A change in the orbital response from eccentricity-to obliquity-forcing, evident from other locations, is well-expressed in the Lorraine Sub-Basin and occurred within the CIE interval. The strong impact of the obliquity component in post-event deposits hints to processes most effective at high latitudes, such as the waxing and waning of polar ice. Paleogeographic features of the Western Tethyan shelf supported the tele-connection of higher to lower latitude processes via water exchange through the Viking Corridor