It is revealed that the lowest 1010 m of the Saint-Ghislain borehole (-4393 to -5403 m), of which cuttings are available, constitutes a crucial source of information to investigate, amongst others, the deep geothermal potential within the Brabant Parautochthon, underlying the Mons Basin, Hainaut. The lithological succession of this interval was reconstructed based mainly on visual analysis and calcimetry of 852 cutting samples as well as four core samples. Additionally, palynological, magnetic susceptibility and X-ray diffraction analyses were conducted in order to complement the dataset. The lower section of the investigated borehole sequence mainly consists of grey calcareous shale while the middle section is dominated by blue-grey shaly limestone and the upper section is mainly composed of green shale. Palynomorphs found at -5261 m suggest an uppermost Givetian–Lower Frasnian age. A new lithostratigraphical interpretation of the deepest part of the Saint-Ghislain borehole is proposed. The lower calcareous shale from -5403 m to -5100 m is interpreted as the Bovesse Formation (Lower Frasnian) and at its base possibly uppermost Givetian. The overlying limestones from -5100 to -4790 m can be attributed to the Rhisnes Formation (Upper Frasnian), and the green shale between ca. -4393 and -4790 m, to the Bois de la Rocq Member (Famennian). These results open new insights regarding the geological interpretation of the basement underlying the Mons Basin. They also present a promising approach and example regarding interpretations based on cuttings. KEYWORDS: Brabant Parautochthon, Mons Basin, Frasnian, Famennian, geothermal energy, Saint-Ghislain borehole
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RBINS Staff Publications 2020
Here we report on anguimorph lizards from the earliest Eocene (MP 7) of the Dormaal locality in Belgium, from the time of the warmest global climate of the past 66 million years. Several clades can be identified in this site: Glyptosauridae, Varanidae, and Palaeovaranidae. Our study focuses on glyptosaurid specimens previously reported from the site, some of which had been provisionally described as a new species,?Placosaurus ragei, and some assigned to an unnamed Placosauriops-like ‘melanosaurine’. Our study presents data on new material, including an almost complete glyptosaurine frontal that has enabled us to assign much of the previously described material to a single genus and species. The specimens that had been assigned to both ?P ragei and the ‘melanosaurine’ share apomorphies (flat osteoderms and chevron-shaped osteoderms) with Gaultia, a glyptosaurid previously known from the earliest Eocene of Wyoming, USA. The Dormaal material represents the first record of this genus outside North America. In fact, the only potential evidence of the occurrence of ‘Melanosaurinae’ in Dormaal might be a single isolated vertebra described here. Here we also describe previously unfigured material of Saniwa and palaeovaranids from Dormaal. The presence of previously reported helodermatids cannot be supported in this Belgian site.
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RBINS Staff Publications 2024 OA
