Delga M.D.,La Pelisserie |
Annales de Paleontologie | Year: 2012
In a recent publication, C. Guernet picks up again the accusations of fraud against J. Deprat, who, in the early 20th century, had suffered such attacks to the point to be removed from the Geological Society of France. At the end of the same century, one among us (M D.D.) reexamined this affair, and drew the conclusion that J. Deprat was innocent, after which the Geological Society of France reinstated him posthumously. The new accusations issued by Guernet are about Deprat's work in Euboea, as well as Corsica and Sardinia. Our own work rather disagrees and shows that, here again, Deprat is innocent. At this occasion, we present or remind new elements about those regions' geology. © 2012 Elsevier Masson SAS.
Di Staso A.,University of Naples Federico II |
Perrone V.,Urbino University |
Perrotta S.,Urbino University |
Perrotta S.,Badley Ashton and Associates Ltd. |
And 2 more authors.
Comptes Rendus - Geoscience | Year: 2010
In the Beni Issef Massif, nearly 30 km west of Chefchaouen (Morocco), the thickest post-nappe succession within the Rifian sector of the Maghrebian Chain seals the tectonic contact between the Intrarifian External Tanger and Loukkos Units, related to the Rifian External Domain. This succession is very important for the reconstruction of the deformation timing of the Rifian Maghrebids. The age of its base, in fact, is an important constraint for defining an upper boundary to the stacking of both the Intrarifian and Maghrebian Flysch Basin Units, because clasts fed by the Melloussa and Numidian Flysch Nappes are abundant in the conglomerate layers. Field and biostratigraphic analyses pointed out the presence of a Lower Beni Issef Fm, unconformable on the Intrarifian External Tanger and Loukkos Units, and an Upper Beni Issef Fm, unconformable on both the Intrarifian Units and the Lower Beni Issef Fm. The Lower Beni Issef Fm, 150 m thick, consists of lenticular conglomerates with huge blocks in a marly-clayey matrix, followed by marls and minor sandstones. It deposited in a siliciclastic platform, shows a fining upward trend and is affected by metre- to hectometre-sized, locally reversed, folds. Samples collected 45-50 m above the base of the formation resulted not older than Late Tortonian in age, but an older age for the base of the formation cannot be excluded. The Upper Beni Issef Fm, up to 550 m thick, starts with coarse conglomerates followed by medium- to coarse-grained well-bedded sandstones and by grey-blue marls and mudrocks. It indicates deposition in a channelized marine delta, with evolution towards pro-delta pelites, and shows sub-horizontal or gently dipping beds towards the east. Biostratigraphic data indicate a probable Messinian age for this formation. The composition of the arenites of both Lower Beni Issef and Upper Beni Issef Fms is quartzolithic and all samples show a notable content of monocrystalline well-rounded quartz and sedimentary lithic fragments. Detrital modes, all falling in the Quartzose Recycled and Transitional Recycled fields, suggest a provenance from recycling of sedimentary successions, easily recognizable in the Flysch Basin and External Units, mainly the Numidian Nappe sandstones. A Tortonian age of the Lower Beni Issef Fm would agree with the Late Serravallian age of the uppermost beds of the External Tanger Unit and indicate that the most probable age for the stacking of the Intrarifian Units falls in the Late Serravallian-Middle Tortonian time span. The Lower Beni Issef Fm was involved in a compressive tectonic phase testified by north-south striking folds. Later, probably during Messinian, the Upper Beni Issef Fm deposited in a younger intramontane basin, resting on both the Intrarifian Units and the Lower Beni Issef Fm. Successively, the Upper Beni Issef Fm was passively transported piggyback on top of the fold and thrust belt during later tectonic evolution of the Rifian Maghrebids. This tectonic evolution results quite similar to that recognized in the Tellian and Sicilian Maghrebids and also in the southern Apennines. © 2010 Académie des sciences.
Durand-Delga M.,La Pelisserie |
Charriere A.,26 rue Jean Pierre Chabrol
Geologie de la France | Year: 2012
At the north-eastern border of the Mouthoumet paleozoic Massif, there limited by the E-W trending North Mouthoumet Fault, Mesozoic formations lay out as a narrow, strongly folded, strip. These formations outcrop in the Serre de Ginoufré (Triassic) and eastward, behind the other side of the « Mouillère Fault », in the Pinède de Durban (Upper Triassic-Upper Cretaceous). The structure of the last one was the subject, for a long time, of conflicting debates. It has been reconsidered, following a new detailed cartography. At the northern part of the Pinède, two little borings in Aptian outcrops have established that these Aptian limestones are there superimposed to Senonian sandstones. This reversed mesozoic series belongs to the overturned limb of a recumbent syncline, directed to the North, which involves Rhaetian to Senonian layers. To the west of the La Pinéde massif, the mainly carbonated Triassic series of the Serre de Ginoufré, with its basement (Ordovician schists), is similarly reversed (Jasse de Riviére area). Moreover Senonian sandstones, overlain by Liassic marls, appear in the little « cote 224 » window below the Triassic layers. This outcrop is interpreted as the local reappearance of levels belonging to the La Pinéde tectonic unit underneath the Serre de Ginoufré tectonic unit. The SSW-NNE « Mouillére Fault »may be interpreted as a deformed and straightened part of the abnormal contact between these two units. Northwards, the Serre de Ginoufré and La Pinéde units are both unconformably overlain by the Begudo- Rognacian beds (Campono? - Maastrichtian continental facies), followed by the Paleocene and Eocene layers. The flat « laramian » tectonic contacts were unsuspected up to now. We interpret these deformations as connected with the displacement, towards the North, of the Mouthoumet paleozoic block. This event was linked to the general compressive context in the Eastern Pyrenees shortly before the end of the Cretaceous times. Afterwards, the uppermost cretaceous features of La Pinéde area were overthrusted by the Triassic-Jurassic formations of the « Nappe des Corbiéres », which is the sinistrally deviated prolongation of the North-Pyrenean zone. This nappe moved to the NW, over the Upper Eocene formations of the Carcassonne Synclinorium. So the structural complexity of the Pinéde de Durban area is due to the superimposition of tangential features, the first one (NNE vergence) during the Maastrichtian (« laramic phase ») followed by the displacement (NW vergence) of the post-Bartonian Nappe des Corbiéres (« Pyrenean phase »).
Contribution of micropaleontology (especially nannofossils) to reconstruct the Miocene geological evolution of the island of Eivissa (Ibiza, Balearic Islands, Spain) [Apport de la micropaléontologie, spécialement du nannoplancton, à la connaissance de lévolution géologique au Miocène de lîle dEivissa (Ibiza, Baléares, Espagne)]
Muller C.,6 bis |
Durand-Delga M.,La Pelisserie
Comptes Rendus - Palevol | Year: 2011
Late Burdigalian to Langhian series (nannoplankton zones NN3 to NN5) are overlying unconformably, or are imbricated with Mesozoic strata of different ages. A description of the marine Cala d'Hort formation is given, which is overlain by the brackish to continental Cape Jueu formation. Based on micropaleontological studies, the presence of Aquitanian is doubtful. The interpretation of a " Langhian fore-deep" with " sedimentary klippen" is discussed. A comparison of the sedimentary sequences and biostratigraphy between Eivissa (Ibiza), the eastern Pre-Betics and Majorca is given. © 2011 Académie des sciences.