bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evolution de l'architecture des monts d'Oujda (Maroc oriental) pendant le Trias et au debut du Jurassique
Authors: Oujidi Mostafa , Elmi Serge 
Published: June 2005

Abstract
Isopach maps of the Triassic-Lower Liassic volcano-sedimentary successions in the Oujda Mountains (eastern Morocco) have been drawn and complemented by the study of the directions of the doleritic dykes. New interpretations of the dynamics of this part of the northern Gondwana margin during the beginning of the Mesozoic rifting are proposed. The tectonic pattern of the Oujda Mountains was controlled by the conjugate motion of N070 degrees E-N090 degrees E (Atlasic) and N150 degrees E-N160 degrees E faults. This extensional regime led to the differentiation of several strike-slip or pull-apart basins delimited by conjugate faults: Oujda, Ahajfoune, Oued El Himer, Tiouli, North Jerada and Metroh depocentres. Some of these are distinct from the others and have sustained a differential subsidence. They have undergone a differential subsidence but this is almost always balanced by the rate of sedimentation and by the basaltic flows which underline the palaeostructures.
Les surfaces a Rhizocorallium de l'Aptien inferieur sur la bordure meridionale du bassin vocontien (France Sud-Est), marqueurs de dynamiques locales; leur relation avec un evenement anoxique global
Authors: Cotillon Pierre , Banvillet Martial , Gaillard Christian , Grosheny Daniele , Olivero Davide 
Published: June 2005

Abstract
On the North-Provence margin, an omission surface with Rhizocorallium often characterizes the sub-Aptian discontinuity between Eocretaceous carbonates and Aptian-Albian marls. This discontinuity is recorded in various successions described along a palaeoslope joining the Vocontian Basin and the Provence platform, between the Jabron valley in the west and the Var valley in the east. The successions including Aptian marls always exhibit an omission surface with Rhizocorallium. Through this area, the Aptian discontinuity equates to at least part of the Goguel Level. The latter is represented by black shales occurring in the Vocontian Basin at the top of Deshayesi zone and is a regional expression of the global anoxic event OAE1a. Thus, the surface with Rhizocorallium can be regarded, on the North-Provence margin, as a marker coincident with the onset of the anoxic event which, in the Vocontian basin, succeeded to a nannoconid crisis. Representing a short event, the surface is also a marker of various processes: (1) current activity, deduced from a dominant orientation of Rhizocorallium. The Barremian-early Aptian carbonate succession is strongly eroded by the formerly more active currents along the Peipin Channel, south-east of Sisteron; these currents also led to the omission of the Bedoulian (= carbonate Lower Aptian) to upper Valanginian series from the top of the hemipelagic palaeoreliefs in the eastern Castellane arc; (2) tectonic activity in the Lower Aptian, marked by N080 degrees to N100 degrees extension faults and slumping of a semi-lithified carbonate sediment. Slumped material and fault scarps are burrowed with Rhizocorallium; (3) differential lithification of the Barremian limestones which has led to distinctive types of current erosion.
Modalites sequentielles de la transgression aaleno-bajocienne sur le sud-est du Bassin parisien
Authors: Durlet Christophe , Thierry Jacques 
Published: June 2005

Abstract
Sedimentologic, biostratigraphic and diagenetic studies made on Middle Aalenian to Lowermost Bathonian deposits in 25 outcrops of the Burgundy High (southeastern Paris basin) lead to a sequence stratigraphy subdivision of the early Dogger record into 7 third order depositional sequences. These sequences make up a second-order transgressive phase whose lower limit is a tectonically enhanced unconformity (the Mid-Cimmerian unconformity), associated with a large scale uplift during the Upper Toarcian and the Lower Aalenian. In the largest outcrops, where the geometry of sedimentary bodies is observable at the hectometre to kilometre scale, the combination of diagenetic, biostratigraphical, spatial and sedimentologic studies is useful to understand the evolution of sediment distribution in the sequences. This approach also allows the measurement of sea level falls at the origin of the sequence boundaries. For example, we show that Lower Bajocian sequences end with decreases of accommodation space &lt;10 m in amplitude, leading to temporary emergences of some reef complexes. Without interrupting the sedimentation on submarine peri-reef pediments during lowstands, these decreases of a few metres of accomodation space can be related to either tectono-eustatic events or thermo-eustatic events.
Integrated stratigraphy across the Paleocene/Eocene boundary in the Contessa Road section, Gubbio (central Italy)
Authors: Galeotti Simone , Angori Eugenia , Coccioni Rodolfo , Ferrari Gabriella , Galbrun Bruno , Monechi Simonetta , Premoli Silva Isabella , Speijer Robert , Turi Bruno 
Published: June 2005

Abstract
An integrated stratigraphic study of the upper Paleocene to lower Eocene Scaglia limestones of the Contessa Road section has allowed us to identify the classical markers of the Paleocene-Eocene transition. The section provides a good magnetostratigraphic record as well as a continuous calcareous nannofossil and foraminiferal biostratigraphy. A negative Carbon Isotopic Excursion (CIE) occurs in the lower part of Chron C24r. The calibration to calcareous plankton zonation indicates that the CIE occurs in the lowermost part of calcareous nannofossil Zone NP10 and the upper part of Zone CP8, that is in the planktonic foraminiferal Zone P5. In the same stratigraphic interval, a distinct turnover in the calcareous benthic foraminifera and a sharp change in the Deep Water Agglutinated Foraminiferal (DWAF) assemblages have been recognised. The record of DWAF, however, indicates a gradual initiation of such a change beginning some 150 k.y. before the CIE and BEE.
Les nucleides cosmogeniques produits in-situ; de nouveaux outils en geomorphologie quantitative
Authors: Siame Lionel L. , Braucher Regis , Bourles Didier L. 
Published: June 2005

Abstract
Measurement of 10 Be and 26 Al concentrations produced by cosmic ray bombardment within the quartz mineral fraction of surficial deposits and exposed bedrocks (in situ-production) is rapidly becoming an important quantitative tool in geomorphology. Whereas conventional methods provide age control on stratigraphic profiles, surface exposure dating using in situ-produced 10 Be and 26 Al is particularly well-suited not only for continuous dating but also for quantifying spatial variations and rates of geomorphic processes.
Le probleme de la limite Cretace-Tertiaire en Corse-du-Sud
Authors: Peybernes Bernard , Cugny Pierre , Fondecave-Wallez Marie-Josee 
Published: June 2005

Abstract
In the autochthonous unit of Punta-di-Calcina (southern Corsica, France), Upper Cretaceous deposits are reworked (clasts of orbitoid-bearing limestones, Globotruncanidae) within marine lowstand breccias of Danian age, that are overlying Jurassic limestones or granitic basement. These Danian breccias can be dated by means of subautochthonous planktonic foraminifera (Globigerinidae and Hedbergellidae), belonging to the Plb and Plc subzones. The K/T boundary coincides with an ante-Danian submarine erosional surface (major unconformity) underlining the gap of the whole Cretaceous. It is probably impossible to find the iridium-level of the K/T boundary along this surface. This stratigraphic framework suggests the occurrence of main (compressional ?) tectonic movements just before the beginning of the Palaeocene, inducing deep erosions on a Corsican-Sardinian block partially covered at this time by Maastrichtian marine carbonate platforms, now disappeared.
La genese et l'interpretation des "fossiles" dans la science classique; de la Renaissance aux Lumieres
Authors: Gaudant Jean , Bouillet Genevieve 
Published: June 2005

Abstract
The main interpretations of fossils from the XVIth to the XVIIIth century are reviewed. They proceed from two philosophical conceptions that were successful at that time: Aristotelism and Neoplatonicism, that were both making reference to occult influences exerted on living beings and mineral world by planets and, more generally, by the whole universe. The acceptance of the organic origin of fossils, near the end of the XVIIth century, followed an obvious weakening of both schools. Consequently, at the beginning of the XVIIIth century, the diluvialist doctrine appeared as being reinvigorated. Similarly, it would be illusive to believe that modern conceptions relative to fossils are totally devoid of any, even implicit, philosophical influence.
Caracteristiques morphologiques et conditions d'apparition de croissants de plage dans des environnements macrotidaux
Authors: Monfort Olivier , Levoy Franck , Larsonneur Claude 
Published: June 2005

Abstract
Beach cusps are sometimes present on the upper foreshore of sandy beaches along the northwest coast of France characterised by very large tidal ranges. These forms were observed on the high tidal zone of Luc-sur-Mer in the "baie de Seine" during morphodynamic surveys conducted between May and July 1996. Topographic surveys showed these cusps to be depositional features. The profile and incident wave characteristics do not favour the theory of cusp formation based on the presence of subharmonic edge waves, while the spacing between the horns is in disagreement with the theory of "self-organisation". The wave record on the lower beach shows, at the time of their appearance, two incident wave trains each with a specific direction and period. The observed beach cusps appear to be induced by the intersection of these two wave trains, thus confirming, for the first time in the field observations, experiments conducted in laboratory.
The formation of the West European Rift; a new model as exemplified by the Massif Central area
Authors: Merle Olivier , Michon Laurent 
Published: June 2005

Abstract
In this paper, we use mainly field data from the Massif Central area, which have been presented in a companion paper [Michon and Merle, 2001], to discuss the origin and the evolution of the West European Rift system. It is shown that the tectonic event in the Tertiary is two-stage. The overall geological evolution reveal a tectonic paradox as the first stage strongly suggests passive rifting, whereas the second stage displays the first stage of active rifting. In the north, crustal thinning, graben formation and sedimentation at sea level without volcanism during the Lower Oligocene, followed by scattered volcanism in a thinned area during Upper Oligocene and Lower Miocene, represent the classical evolution of a rift resulting from extensional stresses within the lithosphere (i.e. passive rifting). In the south, thinning of the lithospheric mantle associated with doming and volcanism in the Upper Miocene, together with the lack of crustal thinning, may be easily interpreted in terms of the first stage of active rifting due to the ascent of a mantle plume. This active rifting process would have been inhibited before stretching of the crust, as asthenospheric rise associated with uplift and volcanism are the only tectonic events observed. The diachronism of these two events is emphasized by two clearly distinct orientations of crustal thinning in the north and mantle lithospheric thinning in the south. To understand this tectonic paradox, a new model is discussed taking into account the Tertiary evolution of the Alpine chain. It is shown that the formation of a deep lithospheric root may have important mechanical consequences on the adjacent lithosphere. The downward gravitational force acting on the descending slab may induce coeval extension in the surrounding lithosphere. This could trigger graben formation and laguno-marine sedimentation at sea level followed by volcanism as expected for passive rifting. Concurrently, the descending lithospheric flow induces a flow pattern in the asthenosphere which can bring up hot mantle to the base of the adjacent lithosphere. Slow thermal erosion of the base of the lithosphere may lead to a late-stage volcanism and uplift as expected for active rifting.
Chronologie de l'ouverture du bassin des Ksour (Atlas Saharien, Algerie) au debut du Mesozoique
Authors: Yelles-Chaouche A. K. , Ait Ouali R. , Bracene R. , Derder M. E. M. , Djellit H. 
Published: June 2005

Abstract
The Ksour mountains (northwest Algeria) belong to the western part of the Saharan Atlas. They are located between the High Plateau to the north, the South Atlas Front to the south and the Moroccan High Atlas to the west (fig. 1a). During the last decades, the Ksour mountains were the focus of several studies, mainly based on sedimentary analyses [Cornet, 1952; Bassoulet, 1973; Baiche, 1975; Ameur, 1978; Ait Ouali, 1991; Mekahli, 1995; Elmi et al., 1998]. These studies indicate that the Ksour mountains correspond to an old asymmetric rift, trending NE-SW, which underwent extension during the Triassic and Liassic [Ait Ouali, 1991; Frizon de Lamotte et al., 2000]. In order to precise the timing of the rifting processes we have analysed subsurface data (seismic lines and borehole data) from the Sonatrach Company.
Syn-depositional, low temperature illite formation at the Jurassic-Cretaceous boundary (Purbeckian) in the Jura Mountains (Switzerland and France); K/Ar and delta 18 O evidence
Authors: Deconinck Jean-Francois , Gillot Pierre-Yves , Steinberg Michel , Strasser Andre 
Published: June 2005

Abstract
K/Ar ages and oxygen isotope compositions were determined on illitic clay fractions of Purbeckian marls from the Swiss and French Jura Mountains in order to examine their syn-depositional origin which had previously been suggested based on sedimentological and mineralogical data. Measured ages range between 122.3+ or -2.3 Ma and 136.5+ or -2.5 Ma, thus being either coeval or slightly younger than the accepted age of sedimentation (Jurassic/Cretaceous boundary). Because total burial depth was less than 1000 m, delta 18 O values around 20 per mil are compatible with a formation of illite by replacement of smectite in an evaporated sea-water. Therefore, in addition to the two common types of illite resulting either from the fragmentation of pre-existing micas or diagenetic formation in deeply-buried sediments, illitic clay minerals formed at low temperature do exist and may be useful for age determination.
Metal ion geochemistry in smelter impacted soils and soil solutions
Authors: Dumat Camille , Chiquet Arnaud , Gooddy Daren , Aubry Emmanuel , Morin Guillaume , Juillot Farid , Benedetti Marc F. 
Published: June 2005

Abstract
As part of an extended project to understand the speciation of metal ions in contaminated lands, we conducted a series of chemical extraction experiments on soil and extracted the soil pore water to determine the speciation of Pb, Cd and Cu in a smelter impacted site. The chemical extractions show that soil organic matter and metal oxides (Fe and Mn) control the speciation of Pb, Cu and Cd in the soil. For Pb, these results are in agreement with previous EXAFS data on the same soils. The soil solution speciation is calculated with the help of the NICA-Donnan modelling approach. The modelling shows that Pb and Cu speciation is dominated by the dissolved organic matter while Cd is mainly in solution as a free aquo-ion. The speciation in the soil is also simulated by a model coupling both the binding to soil organic matter and metal oxides. The simulated partition coefficient (K d ) is in good agreement with the experimentally measured K d .
The Rif mountain building (Morocco); a new tectonic scenario
Authors: Chalouan Ahmed , Michard Andre , Feinberg Hugues , Montigny Raymond , Saddiqi Omar 
Published: June 2005

Abstract
The building of the Alpine Rif belt (southern limb of the Betic-Rif orocline) is restored, mostly based on the Tertiary stratigraphic and metamorphic data set. The Betic-Rif Internal zones derive from an exotic Alboran Terrane partly involved in a S-dipping Betic subduction during the Late Cretaceous ?-Eocene. Incipient collision of the terrane against Iberia triggered back-thrust tectonics south of the Internal mountain belt during the latest Eocene-Oligocene. A N-dipping Maghrebian subduction developed from that time up to Middle Miocene, responsible for the rifting of the internal Alboran Terrane. Docking of the extending Alboran Terrane onto the North African margin occurred during the Neogene through the closure of the Maghrebian Flysch oceanic trough, with southwestward growth of the external accretionary prism, and foredeep subsidence. Subduction zone westward roll back associated with delamination of the dense lithosphere seem to account for the Betic-Rif late orogenic evolution.
Nature and genesis of spodic horizons characterized by inverted color and organic content in a subalpine podzolic soil (Pyrenees Mountains, France)
Authors: Remaury Mireille , Oliva Priscia , Guillet Bernard , Martin François , Toutain Francois , Dagnac Joseph , Belet Jean-Marc , Dupré Bernard , Gauquelin Thierry 
Published: June 2005

Abstract
Podzolic soils showing an inverted sequence between Bh and Bs horizons have been recently described in the French Pyrenees. This paper deals with the spodic characters of two inverted podzol profiles found in the granitic Estibère valley. Taking into consideration a coherent genesis of these soils, we perform this study through a multidisciplinary approach (e.g., pedology, mineralogy). We describe the evolution of the different forms of free iron and aluminum in relation to organic constituents and the mineralogical characteristics of the soil. Spodic criteria indicate that those soils could be classified as podzolic soils. The study of the spodic horizons show the existence of an ochrous horizon “BP1”, rich in immobilized forms of iron (i.e., amorphous and partially crystallized forms). It overlies a darker chocolate colored horizon “BP2” rich in organic-complexed aluminum, aluminosilicate gels and humic constituents, particularly humic acids. We explain the organic accumulation in the deep “BP2” as the result of particular seasonal hydrologic processes related to the geomorphologic and climatogenic situations of the soils profiles.
Polyphased uplift and erosion of the Cévennes (southern France). An example of slow morphogenesis
Authors: Séranne Michel , Camus Hubert , Lucazeau Francis , Barbarand Jocelyn , Quinif Yves 
Published: June 2005

Abstract
The Cévennes are bordering the French Massif Central and the Gulf of Lion margin. The morphogenesis of this area results from an interaction between deep-seated and superficial processes, whose origin and timing is still discussed. We attempt a reconstruction of the surrection and erosion history of the area through a multidisciplinary approach including geology, geomorphology, thermochronology and geochronology. Thermochronology shows that the Cévennes basement underwent some 2 km denudation in mid-Cretaceous time. Analyses of the sediments preserved on uplifted surfaces and in peripheral sedimentary basins indicate a differential surface uplift of the Cevennes, of the surrounding calcareous plateaus, and of the coastal plain, that occurred in several stages during the Tertiary. Early Miocene rifting of the Gulf of Lion margin and opening of the NW Mediterranean drastically modified the drainage network. Geomorphology analyses of the incised rivers and karst network suggest that most of the incision results from uplift that occurred sometime in the Serravalian-Tortonian interval. U/Th dating of calcite concretions in karsts allows to chronologically bracket the formation of some fluvial terraces, and to find very low incision rates during the Pleistocene. Most of the morphogenesis predates the Quaternary. This ongoing study shows an example of polyphased and very slow morphogenesis, with present-day landscape including elements as old as Cretaceous.
Stratigraphic and structural framework of the Neoproterozoic Paracuellos Group, Iberian Chains, NE Spain
Authors: Álvaro J. Javier , Blanc-Valleron Marie-Madeleine 
Published: June 2005

Abstract
The Neoproterozoic Paracuellos Group of the Iberian Chains constitutes the core of two disconnected faulted blocks, named the Paracuellos and Codos antiforms. Precise lithostratigraphic correlations between both areas are not possible due to the structural complexity and because marker beds do not persist laterally. This paper presents a crustal cross-section of the Neoproterozoic axial core (the Paracuellos antiform) based on surface geology, boreholes and seismic reflection profiles. Seismic reflection data reveal that the basement was directly involved by a major Hercynian structure, named here the Paracuellos fault, which splits longitudinally the Paracuellos axial core. In seismic profiles this fault occurs as a northeasterly-dipping reflector (60–70° steep), evidencing a bivergent geometry of the lateral crustal elements.
The sedimentary evolution of the Neoproterozoic Iberian platform ranges from transgressive, non-cyclic, offshore to hemipelagic, black and green shales (Sestrica Formation) to progradational trends recording shoaling during episodes of rapid sediment influx (Saviñán Formation), presumably in response to a low standing sea-level. The siliciclastic succession is punctuated in the inner platform by deposition of phosphatic limestones (Codos Bed), representing a major shoaling event and demarcating a sharp regional change of sedimentation separating two similar siliciclastic tendencies. A diagenetically induced bedded chert (Frasno Bed) occurs in the outer platform, and is interpreted as being the product of at least two silicification episodes. Both the Codos and Frasno Beds are overlain by the Aluenda Formation, which exhibits nearshore to offshore features. An important sedimentary discontinuity appears across the Neoproterozoic-Cambrian transition. The Cambrian(?) Bámbola Formation is paraconformable with the Paracuellos Group displaying a gradual transition in inner platform areas, whereas an erosive unconformity occurs in outer areas. The horizon of the Neoproterozoic-Cambrian boundary is not identified in the Iberian Chains, where neither Cadomian deformation nor discordances are recognisable.
Effect of carbonate ions on pyrite (FeS2) dissolution
Authors: Descostes Michaël , Beaucaire Catherine , Mercier Florence , Savoye Sébastien , Sow Joachim , Zuddas Pierpaolo 
Published: June 2005

Abstract
Neutralization by carbonate of acidification generated by pyrite (FeS2) oxidation was investigated by both solution (iron and sulfur speciation, pH and Eh) and solid (FT-IR) characterizations. Batch dissolution experiments were carried out in contact with atmospheric oxygen (20 %) in four different bicarbonated solutions ([NaHCO3]=10–3, 1,12.10−2, 10−1 and 1 mol/L). Five different contact duration were selected : 6 hours, 1, 3, 8 and 30 days. Ferrous carbonate complexes (FeOHCO3− and Fe(CO3 )22− ) tend to maintain iron in solution (up to 152.2 μmol/L in [NaHCO3]=1 mol/L solution) and to increase pyrite oxidation rate by preventing surface coating. Acidification is thus more intense in diluted and concentrated carbonate medium ([NaHCO3− ] =10–3 and 1 mol/L) with respectively ΔpH=5.06 and ΔpH=1.99 at 30 days whereas pH remains buffered in [NaHCO3− ] =1.12.10−2 and 0.1 mol/L solutions. Siderite appears to be the first solid precipitating, transforming into gœthite, oxyhydroxy ferric sulfate incorporating sulfite and thiosulfate, and then lepidocrocite. Sulfur chemistry controls the acidification observed. Thiosulfate is the first sulfoxyanion released in solution and its oxidation into sulfite then sulfate seems to be the key of acidification production. Thus, carbonate pH buffer properties seem to be limited and effective for moderated carbonate concentrations.