0000000000623217
AUTHOR
Marc Floquet
Drowning of a carbonate platform as a precursor stage of the Early Toarcian global anoxic event (Southern Provence sub-Basin, South-east France)
The Toarcian Oceanic Anoxic Event is well-known as coinciding with a carbonate crisis, coupled with organic matter accumulation and perturbation of the carbon cycle expressed by carbon-isotope excursions. In this palaeoenvironmental setting, the present research attempts to better constrain the palaeoenvironmental conditions leading to the drowning of a carbonate platform during Late Pliensbachian to Early Toarcian times. This study is based on the integrated sedimentological, diagenetic and geochemical (stable isotopes and Rock-Eval pyrolysis) analysis of several stratigraphic successions located in the Southern Provence sub-Basin (South-east France). Eodiagenetic ferroan calcite cements b…
Acanthochaetetidae (Hadromerida, Demospongiae) fromthe Coniacian of Vera de Bidasoa (basque pyrénées, Northern Spain)
Abstract Acanthochaetetes specimens from the Coniacian brecciated limestones near Vera de Bidasoa (Northern Spain) are described. It is the first report of acanthochaetetids from Coniacian strata. The specimens are very small and probably lived in fissures and crevices in fore-reef breccias and deep water mud mounds. The family Acanthochaetetidae Fischer is placed in the order Hadromerida (Tetractinomorpha, Demospongiae). The order Tabulospongida Hartman & Goreau was abandoned.
Mass mortality or exceptional fossilization ? The case of the early and middle Toarcian fossiliferous beds from the Digne-Les-Bains area (southeastern France)
Abstract The latest Domerian to late Toarcian sedimentary series (from −190 Ma up to −180 Ma) from the « Réserve Géologique de Haute-Provence » (southeastern France) yields two kinds of remarkable fossiliferous beds. The greatest interest of the early Toarcian type is the occurrence of ichtyosaur remains (at least in six sites) among many other fossils such as ammonites, belemnites, bivalves, wood. The middle Toarcian type is specifically rich in ammonites and nautiluses. Litho- and biostratigraphical, palaeontological, sedimentological and geochemical analyses allow us to determine whether these fossiliferous beds are the results of mass mortalities, linked or not to biological crisis, o…
The Leiza palaeo-fault: Role and importance in the Upper Cretaceous sedimentation and palaeogeography of the Basque Pyrenees (Spain)
Abstract New analysis of the Upper Cretaceous deposits of the Central Depression, a syncline within the Basque Pyrenees, shows that this structure was a deep marine basin analogous to the regional flysch troughs. It was bounded by active faults, including the Leiza palaeo-fault, which sustained erosion of the partly subaerially exposed margins. The Leiza palaeo-fault and its western counterpart, the Kalamua palaeo-fault, are thought to constitute the former plate boundary between Iberia and Europe, and a westward continuation of the North Pyrenean Palaeo-Fault.