bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analyse tectonique des Schistes du Val Lavagna (unité du Monte Gottero, Apennin ligure). Démonstration stéréogéométrique. Illustration de la notion de réglage tectonique
Authors: Pertusati Piero-Carlo , Horrenberger Jean-Claude 
Published: June 2018

L'analyse tectonique appliquée aux Schistes du Yal Lavagna (Unité du Monte Gottero, Apennin ligure septentrional) a conduit à y distinguer la superposition de plusieurs phases de déformation. La première phase, à caractère régional, correspond à une tectonique tangentielle donnant naissance à des plis isoclinaux couchés, d'ampleur inconnue, de type synschisteux. Schistosité de flux et cristalloblastèse se développent conjointement. Le métamorphisme est de type anchizonal. La seconde phase, également régionale, se manifeste par la mise en place de mégastructures d'amplitude kilométrique, déversées vers le NE. Aux mésostructures correspondent des plis subisoclinaux à charnière généralement concentrique, parfois aplatie et courbée. La schistosité qui leur est associée, souvent en éventail, est soit du type «fracture», soit du type «strain-slip ». Des cisaillements perturbent l'agencement des plis et accentuent la dispersion des structures de la phase précédente. La deuxième phase correspond à une tectonique de serrage. Au cours de son évolution, ce caractère s'exacerbe et conduit au rejeu de l'ensemble des surfaces de discontinuité mécanique. Les phases tardives sont caractérisées par leur style cassant. Cisaillements et décrochements découpent le bâti architectural en une mosaïque de panneaux superposés évoluant indépendamment les uns des autres, sans perturbation des relations spatiales des structures précédemment formées au sein d'un même panneau.
Ces résultats sont présentés en particulier sous la forme de stéréogrammes analytiques-synthétiques, portraits objectifs des secteurs représentatifs choisis.
Sur les aménagements hydrauliques anciens et récents dans le Gourma, Sahel tropical, République du Mali
Authors: Reichelt Rudolf 
Published: June 2018

Древние и современные гидравлические сооружения в гурме (тропический сахель, республика мали).
Большая часть сети цистернов прорытых в почве Гурма, яруе Сахель, открывает гидровлическое оборудование народа уплотненного, возможно, протоисторического прошлого.
Таким образом тут доказано, что система цистернов была устроена и употребляема в период самый сырой.
Решение для его возстановления в Гурма при настоящем сухом климате Должно быть рассмотрено с большой осторожностью.
По-этому предлагается продолжать разведку и эксплуатацию глубоких подземных вод, снабжение которых не завиеит от местных дождей.
Таким о бразом они могут гарантировать постоянные водные пункты — жизненный вопрос Сахеля.
Le paléokarst éocrétacé des Monts Pãdurea Craiului (R.S. de Roumanie) et sa signification dans le mécanisme de genèse des bauxites
Authors: Pop Gheorge , Marza Ioan 
Published: June 2018

Ранемеловои палеокарст гор падиреа креюлуи (д. р. румынии)
и его значение в механизме образования бокситов
Изучением еомелового палеокарста гор Пэдуреа Краюлуй (С. Р. Румыния) и некоторых тексту-ральных особенностей залежей боксита известных внутри этой карстовой системы, раскрыты новые данные для выяснения вторичного происхождения этих залежей, развитых под влиянием двух последовательных, конвергентных процессов осадочного рудообразования.
Воронкообразные («долиновидные ») впадины, во много аналогичны с такими же поверхностными формами рельефа современных тропических карстовых равнин Средней Америки, являлись «западнями », в которых имело место накопление аллохтонных латеритовых продуктов выветривания и постепенное превращение их в бокситы.
Contribution à l'étude du «Continental terminal» dans le Bénin méridional
Authors: Houessou Aurélien , Lang Jacques 
Published: June 2018

The «Continental terminal» s.s., an argillaceous, sandy and conglomeratic formation, rests in unconformable strata upon a series which is continuous from the Cretaceous to the Middle or even Upper Eocene. It is probably a disconformity of the «dissolution and gully erosion» type, which is angular on the map scale. Since the authors have often no proof to point out this disconformity, nor have they arguments for making the «Continental terminal» start with precision.
This «Continental terminal», in a broad meaning, could then include also formations subjacent to the said disconformity, these formations being either continental or marine but having undergone a pedogenetic influence in continental environment. Southern Benin is a privileged area for bringing stratigraphie, palaeogeographic and geodynamic exact informations on the «Continental terminal» s.s. and on the disconformity.
Il Flysch del Cilento nella Catena appenninica
Authors: Ietto Antonino , Calcaterra Domenico , Del Re Maria-Carmela , Gianni Attilio , Pappone Gerardo 
Published: June 2018

II Flysch del Cilento (Complesso liguride), unità strutturale fra le più elevate dell'edificio appenninico nell'Italia méridionale, è formato non da un'unica successione stratigraficamente continua, corne di solito riportato nelle sintesi dell'ultimo decennio, ma da più unità tettoniche fra loro sovrapposte.
Viene proposta una nuova organizzazione di tali unità, per quanto riguarda la litostratigrafia e le possibili correlazioni fra i vari settori dell'Appennino méridionale. I dati qui forniti consentono inoltre un'interpretazione stratigrafico-strutturale delle Unità Silentine fra loro sovrapposte come eteropie più о meno parziali, sempre perô con provenienza interna delle unità medesime rispetto alla tettogenesi appenninica neogenica. L'eteropicità fra le unità sovrapposte nelle medesime successioni e l'analisi dei rapporti fra Unità Silentine e loro insieme e Formazione del Frido mutano'la paleogeografia dei domini di provenienza ; al punto da rendere ispotizzabili nuovi modelli evolutivi del sistema Europa-Tetide-Africa.
Le gîte de Bois Madame (Hérault) : une minéralisation Pb-Zn de milieu confiné en plate-forme carbonatée. The Bois Madame (Hérault, France) ore deposit : a Pb-Zn mineralization in a confined environment on a carbonate platform
Authors: Aubague Maurice , Giot Denis , Sureau Jean-François 
Published: June 2018

Concentrations of iron, zinc and lead sulphides occur in the lower part of the formation known as Bois Madame, of late Upper Kimmeridgian age.
Paleostructural and paleogeographic reconstructions suggest that these concentrations were deposited in a confined area, within a carbonate platform, that was the site for entrapment of calcaro-sapropelic deposits already enriched in metals. The formation was affected by stratiform dolomitization of a distinctive, uniformly fine-grained euhedral textural facies that resulted in the creation of an impermeable barrier at a relatively early diagenetic stage. The main consequences of this were diagenetic maturation in a closed system and protection against external agencies. Another, regional and crosscutting dolomitization originating from the underlying Portlandian reefal dolostones did not affect the Bois Madame formation.
Within their dolomitic envelope, the initial disseminated sulphides are selectively concentrated in the sapropelic horizons. Organic matter play a determining role at several stages in the birth and development of highgrade ore body. Very early during diagenesis it was responsible for the development of reducing conditions that affected the behaviour of the metals : fixation followed by precipitation by bacterial bioreduction of marine sulfates. Also, being distributed in layers, the organic material acted as drains in the relatively impermeable carbonate rocks, thereby allowing the later development of reconcentrations during compaction-dissolution processes.
The orebody is such that, with the syndepositional appareance of the first sulphides followed by an early closure to extend influences, it can be proposed as a model of stratiform syndiagenetic, metal concentration.
Variations de la perméabilité de réservoirs gréseux soumis à percolation de solutions salines. Essais conduits sur grès cohérent. Variation of the permeability of consolidated sandstone subjected to percolation with salt solutions
Authors: Baudracco Joseph , Tardy Yves 
Published: June 2018

This study of coherent and consolidated sandstones follows previous work devoted to clay-rich and unconsolidated sandstone. The variations of the permeability coefficients were measured by various percolating solutions (NaCl. KCl. MgCl₂, CaCl₂), of different concentrations and at several temperatures (20 °C, 60 °C and 90 °C). There are five major results.
(i) The permeability coefficient diminishes as a function of time in all experiments except at 90 °C and I = 1 or 2. (ii ) The temperature has the greatest effect. The permeability coefficient decreases linearly or hyperbolically when temperature increases, (iii) The permeability coefficient depends on the nature of the cation. In diluted conditions (I = 0,01, 1 = 0,1), к decreases as a function of the following cation order : Na &gt; Mg &gt; Ca &gt; K. In solutions of high ionic strength (I = 1 or 2), к decreases in the following order : Na &gt; К &gt; Ca &gt; Mg. Therefore the different sequence orders are not really reliable, (iv) The permeability coefficient к for a given salt tends to diminish when the concentration of the solution increases from I = 0,01 to I = 0. 1 but to increase when the ionic strength rises from I = 1 to I = 2. (v)The effect of any change in the nature of the cations or of the temperature is immediate and. contrary to what observed on uncoherent sandstones. variations are reversible. Thus, the permeability properties of consolidated sandstones seem to depend on the exchangeable cation properties of the clay plasma.
Etude des cuirasses latéritiques dans la région de Dembia-Zémio en Centrafrique. Pétrographie, minéralogie et géochimie. Study of lateric ferricretes in Dembia-Zémio area, Centrafrica. Petrography, mineralogy and geochemistry
Authors: Beauvais Anicet , Mazaltarim Daniel 
Published: June 2018

L'étude pétrographique, minéralogique et géochimique de 56 cuirasses latéritiques a été menée dans la région de Dembia-Zémio en Centrafrique.
D'un point de vue géomorphologique, la région est caractérisée par deux types de modelé cuirassé. Le premier est constitué de deux systèmes cuirassés notés A et B, et du sommet d'un interfluve à une entaille ; les cuirasses se répartissent (i) sur un haut-plateau (1 A), (ii) sur un versant boisé (2A), (iii) sur un bas-versant (3B). Sur la seconde unité de modelé ou système cuirassé C, les cuirasses recouvrent des bas-plateaux (1С et 3C) également entaillés, et qui se trouvent, en moyenne, cinquante mètres plus bas que les hauts-plateaux (1 A).
D'un point de vue pétrographique, les cuirasses de chacun des trois systèmes cuirassés se distinguent les unes des autres par leur faciès : (1) massif dominant sur les hauts-plateaux, (2) pseudonodulaire sur les bas-versants, (3) pseudonodulaire vacuo-tubulaire sur les versants boisés ou les bas-versants, (4) massif scoriacé vacuolaire dominant sur les bas-versants, (S) nodulaire vacuolaire sur les bas-versants et les bas-plateaux, (6) massif vacuo-tubulaire sur les bas-plateaux.
D'un point de vue minéralogique, et en moyenne, (i) les cuirasses des hauts-plateaux sont les plus riches en hématite et kaolinite, mais ce sont les moins goethitiques, (ii) les cuirasses des versants boisés sont les plus gibbsitiques, mais les moins hématitiques, (iii) les cuirasses des bas-versants sont les plus goethitiques et les moins kaolinitiques.
D'un point de vue géochimique, la composition en éléments traces des cuirasses ne reflète que grossièrement la nature du substrat. La lithodépendance est mieux marquée dans les cuirasses des hauts-plateaux que dans les cuirasses de versants.
A high bauxitic surface in the Amazone Territory of Venezuela. Mapping through the Radar-Slar imagery and exploratery examination. Existence d'une haute surface bauxitique en Amazonie vénézuélienne. Première reconnaissance et cartographie à l'aide des images Radar-Slar
Authors: Dubroeucq Didier , Gavaud Michel , Millot Georges 
Published: June 2018

During the geomorpho-pedological survey of the Federal Amazone Territory in Venezuela completed in 1983, considerable bauxitic areas were observed in the highlands (between 1000 and 1400 m) of the crystalline mountains at the east and north of this territory.
These areas are associated with a specific type of landform. Its characteristic pattern reaveled through the Radar-Slar imagery determined its mapping as well as its frontiers in relation with the other lower polyconvex surfaces. This old erosion surface is distributed along an extensive crescent form of 500 km long and 100 km wide which rises above the large turn of the Upper Orenoque river. It stretches over poorly tectonized and often porphyric granites including alkaline types (Surucucu granites, Paraguaza granites).
The field observations evidence a fossil landscape with remarkable uniform aspect. It consists of long interconnected glacis dug out by a rather dense river network with V-shaped narrow valleys in a herring-bone pattern. Locally, the primitive structure has been deeply incised in cuts parallel to the tectonic lineations. The soils are ferrallitic (petroferric gibbsiorthox) with bauxitic hardpan blocks in the upper layer.
The alterite is not very well known from a geological point of view. It is possible to recognize three main horizons up to 8 m deep : a mottled clayey, a soft oxic, and a gravelly horizon with bauxitic hardpan blocks. The mineral composition which is qualitatively constant defines the alteration as intergrade between allitization and fermonosiallitization with an early dehydration state of the oxides : much gibbsite, some Al-goethite, a little hematite and boehmite, very little kaolinite. Downslope in the valleys, the allitic evolution is not so pronounced probably due to the proximity of the bedrock : gibbsite, goethite, some more kaolinite and quartz, traces of weathered minerals, absence of hematite and boehmite.
Anomalie thermique précoce dans le bassin houiller stéphanien de Messeix-Singles, Massif Central français. / Early thermic anomaly in the Stephanian Messeix-Singles coal basin (French Massif Central)
Authors: Robert Patrick , Berquer Claudine , Courel Louis , Kubler Bernard , Robert Paul 
Published: June 2018

Early thermie anomaly in the Stephanian Messeix-Singles coal basin (French Massif Central)
The anthracite occurrence under a small paleocover in the Stephanian Messeix Coal basin is connected with an early thermic anomaly, posterior to the Stephanian В deposition but anterior to the syncline folding dated from end Stephanian. A very early and pretectonic coalification is inferred, with a short hyperthermy. The strong paleorate of temperature growth is shown by the reflectance of vitrinite data, proving a strong coalification. However the low degree of iilite-crystallinity and the occurrence of kaolinite show an apparent low evolution of the mineral assemblages. The thermic anomaly is related to tectonics-controlled water circulations.
L'âge des sols et des formations alluviales du Ried ello-rhénan. Exemple d'un secteur test au Sud d'Illhaeusern, Haut-Rhin. / The age of soils and alluvial materials of the Central Ried of Alsace. Example of a test area near lllhaeusern, Haut Rhin, France
Authors: Al Siddik Abdullah Mohamed , Party Jean-Paul , Mettauer Hubert , Schenck Charles , Guillet Bernard 
Published: June 2018

The age of soils and alluvial materials of the Central Ried of Alsace. Example of a test area near Illhaeusern, Haut-Rhin, France
The soil mapping of a part of the Central Ried of Alsace (Ried ello-rhénan) south of the village of Illhaeusern and observations of soil horizons along a transect demonstrate that peaty formations were buried under alluvial materials. The peat was developed in channels and depressions during the Subboreal period and at the beginning of the Subatlantic. The peaty layers were covered by fine alluvial materials coming from the Ill River or from the Rhine system. The 14C datings of the tops of the peat layers show that the burial of the peat happened sooner at the proximity of the oriental part of the Central Ried. It appears that it is the subsidence of the part of the Ried situated near the Ill River that is responsible for the early deposit of the fine alluvial material.
Solubility of jarosite solid solutions precipitated from acid mine waters, Iron Mountain, California, U.S.A. Solubilité des solutions solides de jarosite précipitées à partir des eaux minières acides, Iron Mountain, Californie, U. S. A
Authors: Alpers Charles N. , Nordstrom Darell.Kirk , Ball James W. 
Published: June 2018

Seven samples of acid mine drainage (initial pH 0.8 to 1.4) from the Hornet and Richmond massive sulfide ore deposits at Iron Mountain, West Shasta district, California, were stored for 1 1 to 13 years at 22 ± 3 °C. A yellow precipitate (Munsell color 2.5 Y 7/8) which formed in each sample is identified by powder X-ray diffraction, atomic absorption spectrophotometry, and thermogravimetric analysis as jarosite solid solution (jss) having the general formula K(x)Na(y)(H₃O)(j.x-y)Fe₃(SO₄)₂(OH)₆, where .53 &lt; x &lt; .83, .03 &lt; y &lt; . 1 5, and .10 &lt;(1-x-y) &lt;.32. It is assumed that at the time of collection in 1974-76, the mine waters were somewhat undersaturated with respect to jss ; subsequent oxidation of aqueous ferrous iron during storage has caused saturation and precipitation of jss. The jss crystals are 5 to 10 micrometers in diameter and rhombohedral in form. The well crystallized nature of the precipitate suggests that the oxidized mine waters have approached thermodynamic equilibrium with jss and therefore can provide useful data for the evaluation of thermodynamic properties of К-Н₃О-Na substitution in jarosite.
Because of the common occurrence of 15 to 25 mole percent hydronium substitution on the alkali site in jarosites, it is necessary to consider the hydronium content of jarosites in any attempt at rigorous evaluation of jarosite solubility or of the saturation state of natural waters with respect to jarosite. A Gibbs free energy of 3293.5 ± 2. 1 kJ mol⁻¹ is recommended for a jarosite solid solution of composition К₇₇Na₀₀₃(H₃O) ₂₀Fe₃(SO₄)₂(OH)₆. Solubility determinations for a wider range of natural and synthetic jarosite solid solutions will be necessary to quantify the binary and ternary mixing parameters in the (K-Na-H₃O) system. In the absence of such studies, molar volume data for endmember minerals indicate that the K-H30 substitution in jarosite is probably closer to ideal mixing than either the Na-K or Na-H₃O substitution.
Géodynamique actuelle du bassin versant de l'Oued Tensift (Maroc) : érosion mécanique et bilan des transports solides fluviaux. / Present geodynamic of the Tensift drainage basin (Morocco) : mechanical erosion and fluvial transports of sediments
Authors: Haida Souad , Snoussi Maria , Latouche Claude , Probst J.L. 
Published: June 2018

Present geodynamic of the Tensift drainage basin (Morocco) : mechanical erosion and fluvial transports of sediments
The aim of this study is to improve the knowledge on sediment mobilization in semi-arid climate through a global estimation of erosion-transport-sedimentation budget in the Tensift drainage basin (Morocco).
The lithological material which could be mobilized by erosion of the main formations has been estimated using simple models to a specific value of 373 t.km-2.an-1. Sediment discharge to Atlantic ocean is calculated using river transport measurements to 200 t.km-2.an-1. This last flux represents 69% of the total sediments potentially eroded in the Tensift basin. The remaining 31% could be attributed to sedimentary deposits in the alluvial plain.
The comparison between the fluvial transports of different floods during the same year exhibits the importance of the hydrological processes in the mechanical erosion control. Moreover, a survey of three hydrological years (dry. mean and humid) allows to follow the present interannual geodynamic evolution of this basin. The sediment budget shows that the climatic factor controls the fluvial transport for the different lithologies. Topography and lithology represent complementary factors, mainly in mountainous part of the drainage basin. Replaced in the whole Maghreb context, the mean values calculated for the Tensift river are in good agreement with those already obtained by various authors (Snoussi et al., 1989 et 1990 ; Probst et Amiotte Suchet, 1992) regarding moroccan. algerian and tunisian rivers. This study confirms the importance of the mechanical erosion and fluvial sediment transports in semi-arid climatic area such as the Tensift draining basin. The sediment yield measured in this region are for example much more higher (1 to 2 order of magnitude) than those observed in tropical Africa.
Light Scattering by Fractal Dust Aggregates. II. Opacity and Asymmetry Parameter
Authors: Tazaki Ryo , Tanaka Hidekazu 
Published: June 2018

Abstract
Optical properties of dust aggregates are important at various astrophysical environments. To find a reliable approximation method for optical properties of dust aggregates, we calculate the opacity and the asymmetry parameter of dust aggregates by using a rigorous numerical method, the T-Matrix Method, and then the results are compared to those obtained by approximate methods: the Rayleigh–Gans–Debye (RGD) theory, the effective medium theory (EMT), and the distribution of hollow spheres method (DHS). First of all, we confirm that the RGD theory breaks down when multiple scattering is important. In addition, we find that both EMT and DHS fail to reproduce the optical properties of dust aggregates with fractal dimensions of 2 when the incident wavelength is shorter than the aggregate radius. In order to solve these problems, we test the mean field theory (MFT), where multiple scattering can be taken into account. We show that the extinction opacity of dust aggregates can be well reproduced by MFT. However, it is also shown that MFT is not able to reproduce the scattering and absorption opacities when multiple scattering is important. We successfully resolve this weak point of MFT, by newly developing a modified mean field theory (MMF). Hence, we conclude that MMF can be a useful tool to investigate radiative transfer properties of various astrophysical environments. We also point out an enhancement of the absorption opacity of dust aggregates in the Rayleigh domain, which would be important to explain the large millimeter-wave opacity inferred from observations of protoplanetary disks.
The Absolute Magnitude of the Sun in Several Filters
Authors: Willmer Christopher N. A. 
Published: June 2018

Abstract
This paper presents a table with estimates of the absolute magnitude of the Sun and the conversions from vegamag to the AB and ST systems for several wide-band filters used in ground-based and space-based observatories. These estimates use the dustless spectral energy distribution (SED) of Vega, calibrated absolutely using the SED of Sirius, to set the vegamag zero-points and a composite spectrum of the Sun that coadds space-based observations from the ultraviolet to the near-infrared with models of the Solar atmosphere. The uncertainty of the absolute magnitudes is estimated by comparing the synthetic colors with photometric measurements of solar analogs and is found to be ∼0.02 mag. Combined with the uncertainty of ∼2% in the calibration of the Vega SED, the errors of these absolute magnitudes are ∼3%–4%. Using these SEDs, for three of the most utilized filters in extragalactic work the estimated absolute magnitudes of the Sun are M

B
= 5.44, M

V
= 4.81, and M

K
= 3.27 mag in the vegamag system and M

B
= 5.31, M

V
= 4.80, and M

K
= 5.08 mag in AB.