bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and testing of a green fluorescent protein-based bacterial biosensor for measuring bioavailable arsenic in contaminated groundwater samples
Authors: Liao Vivian Hsiu-Chuan , Ou Kun-Lin
Published: June 2005

A green fluorescent protein (GFP)-based bacterial biosensor for the detection of bioavailable As(III), As(V), and Sb(III) was developed and characterized. The biosensor strain Escherichia coli DH5α (pVLAS1) was developed based on the expression of gfp under the control of the ars promoter and the arsR gene of Staphylococcus aureus plasmid pI258. Strain DH5α (pVLAS1) responded mainly to As(III), As(V), and Sb(III), with the lowest detectable concentrations being 0.4, 1, and 0.75 μM, respectively, during a 2-h exposure and 0.1 μM for all three metal ions with an 8-h induction period. To assess its applicability for analyzing environmentally relevant samples, the biosensor was field-tested on shallow-well groundwater for which contaminant levels were known. Our results demonstrate that the nonpathogenic bacterial biosensor developed in the present study is useful and applicable in determining the bioavailability of arsenic with high sensitivity in contaminated groundwater samples, and they suggest a potential for its inexpensive application in field-ready tests.
Degradation of citalopram by simulated sunlight
Authors: Kwon Jeong-Wook , Armbrust Kevin L.
Published: June 2005

Citalopram (CIT), 1-(3-dimethylaminopropyl)-1-(4-fluorophenyl)-5-phthalancarbonitrile, a selective serotonin reuptake inhibitor, is one of the most widely used antidepressants for the treatment of anxiety, obsessional, and control disorders. The degradation of the pharmaceutical CIT hydrogen bromide in water was investigated in the dark and in a growth chamber outfitted with fluorescent lamps simulating the ultraviolet output of sunlight at 25°C. No significant degradation could be detected in dark controls in any aqueous solution investigated over a period of 30 d. Citalopram degraded less than 0.5% at pH 5 and pH 7 during the 30-d exposure period under simulated sunlight. However, at pH 9, CIT moderately degraded, with a half-life of 65 d via a pseudo-first order kinetic model. Degradation was faster in synthetic humic water (half-life, 24 d) and in natural waters (half-lives, 14 and 43 d) than in pH 9 buffer, indicating photosensitization by humic acid or other materials in water. Two photoproducts were detected over the irradiation period, and their structures were identified as N-desmefhylcitalopram (DCIT) produced by N-demefhylation as a major product and CIT N-oxide by N-oxygenation as a minor product by liquid chromatography-electrospray ionizationmass spectrometry. The DCIT appeared to be hydrolytically and photolytically stable in aqueous environments. In conclusion, CIT and DCIT were relatively stable in various solutions including natural waters. However, they may dissipate from the aqueous phase to some extent, possibly because of adsorption in real environments where soils and sediments exist.
Des images du systeme lithosphere-asthenosphere sous la France et leurs implications geodynamiques; l'apport de la tomographie telesismique et de l'anisotropie sismique
Authors: Granet Michel , Judenherc Sebastien , Souriau Annie
Published: June 2005

From seismic tomography and seismic anisotropy, images of the lithosphere-asthenosphere system beneath France for some remarkable tectonic areas have been computed : a continental rift system (the Upper Rhinegraben), an Hercynian structure reactivated by Neogene volcanism (Massif central), a region of a recent continental collision (Pyrenees) and finally a region of an ancient orogeny (Armorican Massif). These images have a horizontal spatial resolution of the order of 10 km and show not only the geometry of the deep geological structures but will also illustrate the link between surface observations and structures detected at depth. The images demonstrate the passive character of the Rhinegraben mainly because no low-velocity was found below the Moho, show the presence of a thermal anomaly beneath the Massif central interpreted as caused by a mantle plume in the decaying phase of its evolution and prove the lithospheric scale of the North Pyrenean fault and of the South-Armorican shear zone. The anisotropic measurements suggest a lithospheric deformation related to the most recent tectonic event. In the Pyrenees, the Armorican Massif or the Rhinegraben areas, the directions of the fast-polarisation azimuth (the polarisation direction of the fast shear wave) are parallel to the tectonic texture of the last events, but suggest also a reactivation of inherited Hercynian discontinuities. In the Massif central, the splitting parameters distinguish between two lithospheric units regions marked by a distinct fast-polarisation azimuth on each side of the Sillon Houiller fault zone.
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

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

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

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 <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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.
The industrial waste land of Mortagne-du-Nord (59) – II – Oxidizing alteration of the slags, hydrochemistry, geochemical modelling and remediation proposal
Authors: Schmitt Jean-Michel , Huet-Taillanter Sabine , Thiry Médard
Published: June 2005

The slag backfills of the former sulfuric acid factory of Mortagne-du-Nord (59) are sulfide- and metal-rich (Zn, Pb, Cd). Sulfide oxidation leads to acidification of surficial groundwater and the dispersal of the metals into the environment, by flow towards the rivers which run along the site. The surficial groundwater pHs fall between 2.5 and 6.8 and the metal content is very high, reaching in places 6 000 mg/L of Zn, 2.5 mg/L of Pb and 600 mg/L of Cd. To conceive a remediation scenario, we tried beforehand to understand the phenomena that govern the oxidation of the sulfides. For this purpose, water levels and water compositions have been surveyed every 2 months during 4 years, a geochemical simulation of the alteration/oxidation has been proposed and leaching tests have been performed.

The survey of the water table level and periodical chemical analyses of the groundwater have shown that the slag alteration is reactivated when the water table drops until the sulfide-bearing ≪ fresh ≫ slags are unsaturated. The analysed waters always show an unbalanced negative ionic charge. Geochemical calculations allow to propose several equilibrium models of the waters and to conclude that the presence of thiosulfates (S2O23−) in the original waters most likely explains the observed ionic disequilibrium. The geochemical modelling of the slag alteration, first by percolation in unsaturated conditions (allowing O2 supply) and then under saturated conditions (without O2 renewal), reproduces satisfactorily the chemistry of sampled groundwaters. Leaching tests of the slags have been performed in the laboratory both by percolation (unsatured environment) and by cirulation (saturated and closed environment). These tests allowed to obtain alteration solutions comparable to the waters sampled on site, with progressive ≪ aging ≫ of the material, in agreement with the decrease of the dissolved metals observed on site during the 4-year survey. Moreover, the tests confirm the importance of the oxygen supply in the reactivation of the alteration.

The evolution of the groundwater chemistry, the thermodynamic modelling, as well as the leaching experiments allow to determine with some details the alteration/oxidation mechanism and show that: (1) alteration is actived or reactived after a drop of the water table within the sulfide-bearing facies, (2) the oxygen supply by diffusion in the poral air is the driving force of slag oxidation, and (3) maintaining the backfills in saturated conditions practically stops alteration.

The geochemical evolution of the site is directly related to its history, with successive re-profiling of the channels which have lead to a lowering of the water table of about 2 m. The remediation should be focused on in-situ processing (water treatment aimed to lower acidity, active barriers, …) rather than on ex-situ (excavation) solutions.
Ordovician acritarchs of China and their utility for global palaeobiogeography
Authors: Li Jun , Servais Thomas
Published: June 2005

Since the 1970s, acritarch workers have recognized two distinct geographic acritarch assemblages in the Ordovician. The first assemblage occurs in the late Tremadoc in low latitude areas. This assemblage, recently redefined by Volkova [1997], has been attributed to warm-water environments. A second “Mediterranean” or “peri-Gondwanan” province, attributed to high latitudes in the southern hemisphere, can easily be recognized in late Tremadoc to Arenig acritarch assemblages. This second palaeogeographic “province”, defined by Li [1989] is distributed around the border of Gondwana in a zone reaching from Argentina through northern Africa and peri-Gondwana up to Iran, Pakistan and southern China. In the present work we propose an initial simplified, tentative model of the latitudinal distribution of selected early to middle Ordovician acritarchs. Both “provinces” are plotted on the recent palaeogeographical reconstruction of the early Ordovician of Li and Powell [2001]. It appears that the first “province” is limited to low and intermediate latitudes, i.e., to warmer water environments. However, the generally adopted interpretation that the so called “Mediterranean” or “peri-Gondwanan” geographical assemblage is principally controlled by palaeolatitudes and is considered to be typically “cold-water” has to be revised, because the distribution of this “province” appears related more to the continental arrangement along the Gondwana border than to latitudes. This distribution shows some similarities with recent investigations in Silurian acritarch palaeogeography [Le Hérissé and Gourvennec, 1995] that provides evidence that the global distribution of Silurian acritarchs is under the interdependence of continental arrangement, latitudinal position, environmental conditions and oceanic currents, and that it is not simply latitudinally controlled as previous interpretations have suggested. The Yangtze Plaform of southern China presents elements of both early to middle Ordovician “provinces”, i.e., from both the “warm-water” and the “peri-Gondwanan” geographic assemblages. The South China Plate is therefore one of the areas that shows typically mixed assemblages. Although it remains difficult to define clearly a “Baltic” province, it is important to note that between the latest Tremadoc and the early Llanvirn a clear distinction of the acritarch assemblages between peri-Gondwana and Baltica is possible.
A new specimen of Spinosaurus (Dinosauria, Theropoda) from the Lower Cretaceous of Tunisia, with remarks on the evolutionary history of the Spinosauridae
Authors: Buffetaut Eric , Ouaja Mohamed
Published: June 2005

A newly discovered incomplete dinosaur dentary from the Chenini Sandstones (early Albian) of Jebel Miteur (Tataouine Governorate, southern Tunisia) is extremely similar to the corresponding part of the type of Spinosaurus aegyptiacus STROMER, 1915, and is identified as Spinosaurus cf. aegyptiacus. A review of African spinosaurids shows that baryonychines were present in the Aptian, and apparently became replaced by spinosaurines in the Albian and Cenomanian, perhaps as part of a more general faunal change between the Aptian and Albian. Spinosaurines may have been derived from the less advanced baryonychines. Several alternative hypotheses about the biogeographical history of the Spinosauridae are discussed.
Early record of tectonic magnetic fabric during inversion of a sedimentary basin Short review and examples from the Corbières transfer zone (France)
Authors: De Lamotte Dominique Frizon , Souque Christine , Grelaud Sylvain , Robion Philippe
Published: June 2005

An integrated study combining anisotropy of magnetic susceptibility (magnetic fabric) and analysis of meso-scale structures is presented. The studied sites, which belong to the Corbières transfer zone (France), suffered a clear polyphase deformation. The magnetic fabric is of tectonic origin and records an early layer parallel shortening. In general, this primary fabric is not altered by later deformations including folding. However, secondary fabrics have been observed in the vicinity of major faults. They are probably related to tectonically driven fluids migrating along these planes. Consequences on interpretation and use of magnetic fabrics in inverted sedimentary basins are discussed.
Cartography of the Ronda peridotite (Spain) by hyperspectral remote sensing
Authors: Launeau Patrick , Sotin Christophe , Girardeau Jacques
Published: June 2005

The Ronda Peridotite, south of Andalusia (Spain), was imaged by AVIRIS in 1991 and partially sampled by us in the field with a GER 3700 spectrometer in 1997 in order to get experience in processing hyperpectral images of planetary surfaces with probes such as ISM Phobos (1989), OMEGA Mars Express (2003) and VIMS Cassini (2004). The high spectral resolution of the images (224 channels from 400 to 2455 nm) is necessary to conduct geological analysis with remote petrological determinations of rock types. On Earth, it is also necessary to determine species of vegetation because of their strong influence in mapping lithology, even in dry areas like the Ronda peridotite.

The Ronda AVIRIS image was first processed to infer geological features using photo-interpretation of colour composite images extracted from 150 useful channels compared to geological maps and checked on the field during the campaign of July 97. This allows us to distinguish easily the peridotite massif from its surrounding rocks and its own serpentine zoning.

Since this work followed the work of Chabrillat et al. [2000] we chose to explore the AVIRIS data with other techniques. We chose to remove the contribution of the atmosphere with spectra collected in the field on a white target at various altitudes and to remove the main vegetation with spectra of the most characteristic vegetation of the peridotite. In both cases we first estimated the amount of atmosphere and vegetation with band ratios and remove them with two similar empiric corrections of the reflectance.

From the spectroscopy data, after removal of the atmosphere and some vegetation signal, we were able to clearly distinguish the crustal rocks from the mantle ones, as well as compositional variations due to pyroxene and mostly serpentine abundance within the peridotites. Hyperspectral infrared spectrometry will provide good geological mapping of the main rocks on planetary surfaces, if images can also be calibrated with in situ field measurements which will not miss any unexpected component. However, some ambiguities remain between certain types of rock which have close mineralogical composition (e.g. harzburgite compared to lherzolite) or which have resulting spectra very similar to each other (plagioclase and lizardite in peridotites). Some other ambiguities between spectra are also introduced by techniques of analysis based on relative reflectance. By not taking into account absolute intensity of the reflectance, because of roughness and topographic shading effects, small mineral variations are not always visible.
The syn-rift sedimentary cover of the North Biscay Margin (bay of Biscay): from new reflection seismic data
Authors: Thinon Isabelle , Réhault Jean-Pierre , Fidalgo-González Luis
Published: June 2005

The Armorican Basin is a deep sedimentary basin lying at the footside of the North Bay of Biscay. From previous scattered inadequate data, the age and nature of this basin, oceanic domain or deep part of the Armorican margin itself were largely speculated. From this new seismo-stratigraphic study based on a dense seismic cover, the sedimentation within the Armorican Basin is beginning in the Aptian times, during the last tectonic rifting episode of the margin. The first sediments formation identified as the « 3B layer » is characterised on the profiles by a chaotic and transparent seismic facies and was emplaced by slumping process when the margin collapsed, at the final rifting phase, just before the oceanic accretion.

The new seismic reflection data give also some informations on the polyphased evolution of the North Biscay Margin during the rifting period. Two main events occurred during the Lower Cretaceous times (the first one is pre-Berriasian, the second is Aptian), separated by a quiet tectonic period including the Upper Berriasian and Lower Aptian times. The first event is responsible of the margin tectonic structuration in some blocks, the second of collapsing and the emplacement of the allochthonous sediments (3B layer) in the Armorican Basin.
Early Ordovician acritarchs of the Lierneux Member (Stavelot Inlier, Belgium): stratigraphy and palaeobiogeography
Authors: Vanguestaine Michel , Servais Thomas
Published: June 2005

The messaoudensis-trifidum acritarch microflora is currently considered to be characteristic of latest Tremadocian-earliest Arenigian cold-water environments on the periphery of Gondwana, at high latitudes in the southern hemisphere. Integrated biostratigraphical studies on both acritarchs and graptolites are available from two areas of peri-Gondwana, the Lake District (northwestern England) and the Sierra Morena (southwestern Spain). The assemblage was also recorded from other areas on the northern border of the Gondwana continent where macrofossils are generally not available: from southern Ireland, the Isle of Man, southern Wales, the island of Rügen in northern Germany, the Prague Basin in the Czech Republic, and southern Turkey. While it appears that the messaoudensis-trifidum acritarch assemblage is limited to cold-water environments in localities on the periphery of Gondwana, some of its elements can be found in other areas. Some taxa, but not the complete assemblage, have been identified in the eastern Cordillera of Argentina, and some species of the assemblage are cited from continents which were situated at intermediate latitudes in warmer waters: some elements of the assemblage are described from localities of Baltica (from Norway, Estonia and the St. Petersburg area in northwestern Russia) and from the Yangzte Platform in southern China. In these regions, typical representatives of the messaoudensis-trifidum assemblage co-occur with taxa typical of temperate and warm-water areas.

The present paper reports the discovery of the messaoudensis-trifidum acritarch assemblage in the Lierneux Member (Stavelot Inlier, Belgium). The Lierneux Member, which constitutes the uppermost part of the Jalhay Formation (formerly Salmian 1c) in the Stavelot Inlier, was first dated as late Tremadocian by Vanguestaine [1992a]. Following recent stratigraphical conclusions based on the detailed investigations of the messaoudensis-trifidum assemblage from different sequences of peri-Gondwana, the age of the Lierneux Member recovered from the Chevron borehole in the Stavelot Massif can now be confirmed as being probably latest Tremadocian. The discovery of the messaoudensis-trifidum assemblage in the Stavelot Inlier provides further evidence for the palaeogeographical distribution of the assemblage on the northern border of Gondwana and allows tentative correlations between eastern Belgium and northern Germany.
Ashgillian graptolite fauna of the Yangtze region and the biogeographical distribution of diversity in the latest Ordovician
Authors: Chen Xu , Melchin Michael J. , Fan Jun-xuan , Mitchell Charles E.
Published: June 2005

Ashgillian graptolites have been described and recorded globally from 15 different paleoplates. The most diverse graptolite faunas are from the Yangtze region, South China, including 28 genera and 96 species. Among them, 25 genera and 73 species belong to the DDO fauna (Dicranograptidae – Diplograptidae – Orthograptidae fauna), and only three genera but 23 species belong to the N fauna (Normalograptidae fauna). Among the Yangtze graptolite fauna there are six endemic genera and 51 endemic species, which represent 21% and 52%, respectively, of the Ashgillian fauna in the region. This is an unusually high level of endemism. Endemic species are present in both the endemic and the cosmopolitan genera.

A late Ashgillian stepwise extinction event has recently been recognized, based on graptolite diversity changes and graphic correlation. This begins with a major extinction from the Diceratograptus mirus Subzone to the middle Normalograptus extraordinarius-N. ojsuensis Zone, and ends with a minor extinction prior to the end of the Normalograptus persculptus Zone. Graptolite faunal replacement of the DDO fauna by the N fauna occurred throughout this interval.

A comparison of Ashgillian graptolite diversity between the Yangtze region and other regions indicates that two different biogeographical realms existed in mid-Ashgillian time. A moderate-diversity graptolite fauna is present in the low-middle latitude realm, which includes South Scotland, Kazakhstan, Kolyma, Nevada, Yukon, Canadian Arctic, SE Australia. The Yangtze region was located in this realm, but was characterized by a very high-diversity fauna. Some other localities, including eastern Avalonia (Wales and England), the Argentina Precordillera, and Bohemia, which mainly represent the mid- to high-latitude realm, contain the lower-diversity mid-Ashgillian assemblages. This biogeographical distribution suggests a latitudinal diversity gradient, which may be controlled mainly by water temperature. This climate gradient becomes much less evident by late Hirnantian time in which most parts of the world have a relatively low diversity fauna totally dominated by normalograptid species, many of which appear to have been eurytopic. Throughout the Ashgillian, however, the Yangtze platform shows a high diversity and long persistence of DDO taxa the mass extinction interval. This may be a consequence of the semi-restricted nature of the basin in which conditions relatively favorable to graptolite survival and speciation existed throughout all or most of the Hirnantian.
Some Cretaceous long-looped terebratulide brachiopods analysed in the light of the diversity observed in the ontogeny of Recent representatives
Authors: Gaspard Danièle
Published: June 2005

The shape of the loop is of prime importance in brachiopod terebratulide classification and has been widely discussed and revised [Williams et al., 1996]. In the Rhynchonelliforma, we have focused our attention on the Terebratellidina, long-looped brachiopods with a wide-range diversity. The observation of its internal structure in recent representatives, investigated from the early growth stages, using the Scanning Electron Microscope (S.E.M.), demonstrates the complexity of its growth. Two main growth types of the descending branches are expressed during early ontogeny [Gaspard, 2002], followed in both cases by forward growth in opposite directions, with a brachial ribbon attached or unattached to the median septum. The purpose of such observations is to find in the fossil records similar growth types. An approach from the recent representatives allows a better knowledge of the Cretaceous taxa considered, even if the only way to recognise the loop is by means of transverse serial sections. The study of the recent terebratellidine loop facilitates the establishment of links between species from different geological periods. It helps to determine superfamilial distinctions and to find possible ancestors of recent terebratellidines.