COMMENTS ON SOME SYRINGOTHYRIDOIDEA (BRACHIOPODA) FROM THE CARBONIFEROUS OF NORTH AFRICA

The type species of the spiriferinide genus Histosyrinx Termier & Termier (Brachiopoda), namely Histosyrinx vautrini Termier & Termier, is re-investigated in detail on the basis of its type material from the Tournaisian Marar Formation (Serdeles area, Murzuq Basin, Libya), including additional specimens from the same region, and from the Tournaisian of Algeria (Reggane Basin). The internal morphology of the ventral valve of Histosyrinx vautrini is particularly variable, notably concerning the development of the septal pillow, the subdelthyrial plate and the median septum. Histosyrinx can be easily distinguished from the genus Septosyringothyris Vandercammen by the absence of a true delthyrial plate and the lesser development of the median septum. Histosyrinx is also close to Syringopleura Schuchert, which is generally considered as a synonym of Syringothyris Winchell, by its ventral internal features (e.g. development of a septal pillow), but the dorsal internal morphology of the type species of Schuchert’s genus remains unknown. Thus, the relationships between both genera need to be investigated further. Specimens from the southern margin of the Tindouf Basin (Algeria), previously identified as Septosyringothyridinae? gen. indet. by Legrand-Blain in the 1970s, are fully illustrated here for the first time and referred to an unidentified genus of the subfamily Permasyrinxinae on the basis of the absence of syrinx. &nbsp

Introduction to the geology of the Heid des Gattes at Sougné-Remouchamps (Liège province, Belgium)

Introduction à la géologie du site de la Heid des Gattes à Sougné-Remouchamps (province de Liège, Belgique) où sont exposées les formations de la Famenne, d'Esneux, de Souverain-Pré, de Comblain-la-Tour, de Montfort et d'Evieux (Dévonien supérieur (Famennien).Introduction to the geology of the Heid des Gattes at Sougné-Remouchamps (Liège province, Belgium) where the Famenne, Esneux, Souverain-Pré, Comblain-la-Tour, Montfort and Evieux formations (Upper Devonian, Famennian) are exposed

The red crinoidal limestone of Baelen (late Upper Devonian), a particular historical building stone with an unusual depositional setting, global geological importance and local use

Peer reviewe

Lower Devonian rhynchonellid brachiopods from the Ougarta area (western Sahara, Algeria)

The description and study of rhynchonellid brachiopods recently collected from the Lower Devonian of the Ougarta area in western Algerian Sahara permitted the revision of previously described and/or listed taxa, mainly from Morocco. Palaeobiogeographically, the nine identified taxa share many similarities with the rhynchonellid fauna of the Ibarmaghian Domain. Five of the nine identified taxa belong to three genera of the Family Nucinulidae Sartenaer, 2004. Three of these are new taxa, namely Nucinulus orbignyanus crassicostus subsp. nov., Cuninulus ougartaensis sp. nov. and Palinulus saharaensis sp. nov. The our remaining taxa are assigned (one of them questionably) to the genera Lanceomyonia, Stenorhynchia and Glossinulus of the families Hebetoechiidae, Trigonirhynchiidae, and Glossinotoechiidae, respectively.Peer reviewe

New data on the incertae sedis biota and foraminifera of the mid-Famennian Baelen Member (Late Devonian, eastern Belgium)

The Baelen mud mounds in eastern Belgium represent a local member of the mid-Famennian Souverain-Pré Formation (an important carbonate interval within the Condroz Sandstone Group). The lower part of this member contains silty bioclastic wackestones and packstones that are particularly rich in the problematical algae Serrisinella and Dreesenullella. Plurilocular foraminifera (Septabrunsiina and Baelenia) and rare solitary rugose corals (Neaxon? sp.) occur within crinoidal grainstones (tempestites) interfingering with the latter bioclastic wacke-/packstones and red-stained stromatactoid spiculitic mudstones (carbonate mound core facies). Although Serrisinella is quite common in other mid- and late Famennian limestones, of Belgium, Dreesenulella is almost endemic of the Baelen Member. Both genera apparently inhabited the muddy sediment-water interface, constituting meadows probably in zones of intermittently strong bottom currents. The taxonomic similarities between Dreesenulella and Saccamminopsis are discussed, as well as their possible affinities with the Xenophophyrea and Kokomiacea. Moreover, the first stages of the Septabrunsiina–Baelenia foraminiferal lineage are analysed in detail. The taxonomic and palaoecological positioning of Serrissinella and Dreesenulella adds to the discussion about the palaeobathymetry of the Baelen mud mounds and corroborates sedimentological evidence for their relatively shallow carbonate ramp depositional setting

L'origine des mégalithes du Fond de Quarreux (Ardenne, Belgique)

Une étude de la répartition de mégalithes dans la vallée de l’Amblève à sa traversée des quartzites d’âge Cambrien de la Formation de La Venne à l’extrémité occidentale de la crête de la Vecquée a été réalisée. Elle a permis de montrer que les fortes concentrations présentes au Fond de Quarreux s’expliquent essentiellement par des apports des versants adjacents en environnement périglaciaire. L’étude sédimentologique de dépôts des vallées de la Chefna, du Ninglinspo et de l’Amblève elle-même permet de situer dans le Dryas récent des dépôts périglaciaires de couverture. Les mécanismes qui ont conduit à la situation actuelle ont agi de la même façon pendant tous les stades isotopiques marins (S.IM.) les plus froids du Quaternaire, c’est-à-dire les stades pairs #22 à #2. L’application de la force tractrice critique et de la puissance spécifique critique au calcul de la compétence de l’Amblève montre que le cours d’eau ne peut déplacer des blocs de plus 50 cm de diamètre dans les conditions climatiques actuelles. Il en résulte que les radeaux de glace ont dû assurer en climat périglaciaire l’essentiel de l’évacuation des mégalithes qui se sont trouvés dans le lit du cours d’eau depuis qu’il est incisé dans les quartzites cambriens de la Formation de La Venne.Origin of megaliths of the Fond de Quarreux (Ardenne, Belgium). Distribution of megaliths was studied in the Ambleve valley throughout its gorge developed within the quartzites of the Cambrian-aged La Venne Formation (Fond de Quarreux) in the south-eastern part of high Belgium. The high concentration of megaliths at this place can be essentially explained by mass movements which have occurred on the adjacent slopes in periglacial periods of cold Ocean Isotopic Stages in Quaternary times, and especially the coldest ones i.e. even O.I.S.#22 through #2. Stratigraphical studies of deposits in the Chefna and Ambleve valleys allowed us to place final periglacial deposits during the Younger Dryas. The critical shear stress and the critical unit stream power are used in order to evaluate the Ambleve River competence. It results that, under the present climatic conditions, this river cannot move boulders of more than 50 cm in diameter. Hence, it is concluded that ice rafting has been the main process responsible for carrying away the megaliths which have got the Ambleve river bed throughout the Quaternary Period.Peer reviewe