Des dents isolées de chondrichthyens du Sinémurien (Jurassique Inférieur) du sud de la Belgique sont décrites. Celles-ci permettent de signaler la présence des neosélaciens Agaleus sp., Synechodus enniskilleni, Synechodus occultidens et des hybodontiformes Hybodus medius, Hybodus raricostatus, Hybodus reticulatus, ? Lissodus cf. pattersoni en Belgique. Ceci élargit la distribution paléographique de l'espèce et accroit notre connaissance de la diversité des chondrichthyens du Jurassique belge.
Un niveau condensé à ossements du Toarcien inférieur (Jurassique Inférieur) a fourni, à Aubange (Lorraine belge), une faune de chondrichthyens comprenant des Hybodontidae, des Synechodontiformes, ainsi qu'une nouvelle espece, <em>Welcommia terencei nov. sp.</em>, rapprochée des Hexanchiformes.
A clay-rich Callovo-Oxfordian sedimentary formation was selected in the eastern Paris Basin (MHM site) to host an underground laboratory dedicated to the assessment of nuclear waste-disposal feasibility in deep geological formations. As described initially, this formation shows a mineralogical transition from an illite-smectite (I-S) mixed-layered mineral (MLM), which is essentially smectitic and randomly interstratified (R = 0) in the top part of the series to a more illitic, ordered (R≥1) I-S in its deeper part. This description has been challenged by using the multi-specimen method developed by Drits et al. (1997a) and Sakharov et al. (1999). It is shown that all samples contain a physical mixture of an unusually (?) illitic (~65% I) randomly interstratified I-Exp (illite-expandable MLM) and of a discrete smectite, in addition to discrete illite, kaolinite and chlorite. Structural parameters of the different clay phases vary little throughout the series. According to the proposed model, the mineralogical transition corresponds to the disappearance of smectite with increasing burial depth. Comparison with clay minerals from formations of similar age (Oxfordian–Toarcian) throughout the Paris Basin shows that the clay mineralogy in the deeper part of the series originates from a smectite-to-illite transition resulting from a low-temperature burial diagenesis. The anomalous lack of evolution of clay minerals in the upper part of the series is thought to be related to specific interactions between organic matter and clay minerals.
Palaeo-heat flow values and thicknesses of eroded Permo-Carboniferous sediments in the Saar Basin were evaluated using one dimensional thermal modelling techniques. Thermal, burial and erosion histories for 16 wells were calibrated by comparing measured and calculated vitrinite reflectance using the kinetic EASY%Ro algorithm and by comparing measured and calculated temperature data. On the basis of 37 wells, coalification maps were constructed revealing a syn-kinematic coalification pattern. Thermal maturity of the sediments can only be explained by deep burial and moderate heat flows during time of maximum burial, i.e., in the Permo-Carboniferous. Calculated heat flow data range between 50 and 75 mWrm2, which implies a crustal thickness between 30 and 40 km during the time of maximum burial. These values are in accordance with the geodynamic setting of the basin. The influence of the Permo-Carboniferous volcanism on the palaeo-temperature distribution was overwhelmed by the subsequent deep burial. During Permian times, between 1800 and 3000 m of Permo-Carboniferous sediments were eroded. Different sedimentation and erosion histories are characteristic for anticlines and synclines, respectively.
