Flora das Culturas Agrícolas da Ilha de Santiago (cabo Verde)

Com o objectivo de caracterizar as comunidades vegetais que acompanham as culturas agrícolas de sequeiro e de regadio praticadas em Santiago e, particularmente, no vale da ribeira Seca, efectuaram-se 16 levantamentos titoecológicos ao longo deste curso de água e encostas sobranceiras. A inventaria@0 floristica revelou a presenta de 118 taro pertencenteas 3 3 familias. Analisaram-sea, inda,6 2 levantamentorse alizadose m diversosp ontosd a ilha, tendo sido identificados1 72t axa pertencenteas 42 familiasG. ramineae. Leguminosae e Compositue sao as famílias melhor representadasA. flora inventariadaC comparadac om a referida em trabalhos precedentesr,e alizadosp or outrosa utores,r evelandolao correnciad e, pelo menos,1 82t axa na flora infestante. Os levantamentos da ribeira Seca foram analisadosa travt5sd o programad e análise numérica TWINSPAN, que indicou a presentad e 4 agrupamentosv egetais distintos, cuja interpretacao,a tendendoà s característicase dáticas,c limáticase topográticasd os locais onde ocorrem,s ugeriua disponibilidadeh idrica comoo factorm aisd eterminantde as uac omposicáo. Palavras-chavefl:o ra, adventiciasd asc ulturasT, WINSPAN, ilhasd eC aboV erde, Santiago. In order to identify and to characterizeth e plant communitiesp resenat t the irrigated and dry cropso f ribeira Secav alley, it were established16 s amplep lots. The tloristic inventory has revealedt he presenteo f 118 tara belongingt o 33 families.I n addition,m ore 62 samplep lots,were establishedth roughoutt he island,w hich permittedt he identifkation of 172t ara from 42 families.G ramineae, CompQsitae &ndL eguminosae weret he mostr epresentativeosn es.T his flora is comparedw ith that referred in precedingw orksf rom othersa uthors,r evealingt he occurrence of, at least, 182 tma in the weed flora. The application of the TWINSPAN numerical analysis, to the plots in the ribeira Seca vallcy. has revealed the presente of 4 distinct plant communities, which were related with edaphic,c limatic and topographicf actors.T his analysiss uggestetdh at the water availability wa.s the mainf actor affecting the speciesc ompositionof the communities. Key-words:f lora weedsT, WINSPAN, CapeV erdei slandsS, antiago.

Two-stage, extreme albitization of A-type granites from Rajasthan, NW India

Albitization is a common process during which hydrothermal fluids convert plagioclase and/or K-feldspar into nearly pure albite; however, its specific mechanism in granitoids is not well understood. The c. 1700 Ma A-type metaluminous ferroan granites in the Khetri complex of Rajasthan, NW India, have been albitized to a large extent by two metasomatic fronts, an initial transformation of oligoclase to nearly pure albite and a subsequent replacement of microcline by albite, with sharp contacts between the microcline-bearing and microcline-free zones. Albitization has bleached the original pinkish grey granite and turned it white. The mineralogical changes include transformation of oligoclase (similar to An(12)) and microcline (similar to Or(95)) to almost pure albite (similar to An(0 center dot 5-2)), amphibole from potassian ferropargasite (X-Fe 0 center dot 84-0 center dot 86) to potassic hastingsite (X-Fe 0 center dot 88-0 center dot 97) and actinolite (X-Fe 0 center dot 32-0 center dot 67), and biotite from annite (X-Fe 0 center dot 71-0 center dot 74) to annite (X-Fe 0 center dot 90-0 center dot 91). Whole-rock isocon diagrams show that, during albitization, the granites experienced major hydration, slight gain in Si and major gain in Na, whereas K, Mg, Fe and Ca were lost along with Rb, Ba, Sr, Zn, light rare earth elements and U. Whole-rock Sm-Nd isotope data plot on an apparent isochron of 1419 +/- 98 Ma and reveal significant disturbance and at least partial resetting of the intrusion age. Severe scatter in the whole-rock Rb-Sr isochron plot reflects the extreme Rb loss in the completely albitized samples, effectively freezing Sr-87/Sr-86 ratios in the albite granites at very high values (0 center dot 725-0 center dot 735). This indicates either infiltration of highly radiogenic Sr from the country rock or, more likely, radiogenic ingrowth during a considerable time lag (estimated to be at least 300 Myr) between original intrusion and albitization. The albitization took place at similar to 350-400 degrees C. It was caused by the infiltration of an ascending hydrothermal fluid that had acquired high Na/K and Na/Ca ratios during migration through metamorphic rocks at even lower temperatures in the periphery of the plutons. Oxygen isotope ratios increase from delta O-18 = 7 parts per thousand in the original granite to values of 9-10 parts per thousand in completely albitized samples, suggesting that the fluid had equilibrated with surrounding metamorphosed crust. A metasomatic model, using chromatographic theory of fluid infiltration, explains the process for generating the observed zonation in terms of a leading metasomatic front where oligoclase of the original granite is converted to albite, and a second, trailing front where microcline is also converted to albite. The temperature gradients driving the fluid infiltration may have been produced by the high heat production of the granites themselves. The confinement of the albitized granites along the NE-SW-trending Khetri lineament and the pervasive nature of the albitization suggest that the albitizing fluids possibly originated during reactivation of the lineament. More generally, steady-state temperature gradients induced by the high internal heat production of A-type granites may provide the driving force for similar metasomatic and ore-forming processes in other highly enriched granitoid bodies.

Dispersion of natural arsenic in the Malcantone watershed, Southern Switzerland: field evidence for repeated sorption-desorption and oxidation-reduction processes

In recent years, elevated arsenic concentrations have been found in waters and soils of many, countries, often resulting in a health threat for the local population. Switzerland is not an exception and this paper deals with the release and subsequent fate of arsenic in a 200-km(2) mountainous watershed, characterized by crystalline silicate rocks (gneisses, schists, amphibolites) that contain abundant As-bearing sulfide ore deposits, some of which have been mined for iron and gold in the past. Using analytical methods common for mineralogical, ground water and soil studies (XRD, XRF, XAS-XANES and -EXAFS, electron microprobe, extraction, ICP, AAS with hydride generator, ion chromatography), seven different field situations and related dispersion processes of natural arsenic have been studied: (1) release by rock weathering, (2) transport and deposition by water and ice; (3) release of As to the ground and surface water due to increasing pH; (4) accumulation in humic soil horizons; (5) remobilization by reduction in water-saturated soils and stagnant ground waters; (6) remobilization by using P-rich fertilizers or dung and (7) oxidation, precipitation and dilution in surface waters. Comparison of the results with experimental adsorption studies and speciation diagrams from the literature allows us to reconstruct and identify the typical behavior of arsenic in a natural environment under temperate climatic conditions. The main parameters identified are: (a) once liberated from the primary minerals, sorption processes on Fe-oxy-hydroxides dominate over Al-phases, such as Al-hydroxides or clay minerals and limit the As concentrations in the spring and well waters between 20 and 300 mug/l. (b) Precipitation as secondary minerals is limited to the weathering domain, where the As concentrations are still high and not yet too diluted by rain and soils waters. (c) Although neutral and alkaline pH conditions clearly increase the mobility of As, the main factor to mobilize As is a low redox potential (Eh close or below 0 mV), which favors the dissolution of the Fe-oxy-hydroxides on which the As is sorbed. (d) X-ray absorption spectroscopy (XAS) of As in water-logged humic forest soils indicates that the reduction to As III only occurs at the solid-water interface and that the solid contains As as As V (e) A and Bh horizons of humic cambisols can effectively capture As when As-rich waters flow through them. Complex spatial and temporal variation of the various parameters in a watershed results in repeated mobilization and immobilization of As, which continuously transports As from the upper to the lower part of a watershed and ultimately to the ocean. (C) 2004 Elsevier B.V. All rights reserved.

Carbon and oxygen isotope study of hydrothermal carbonates in the zinc-lead deposits of the San Vicente district, central Peru: A quantitative modeling on mixing processes and CO2 degassing

Carbon and oxygen isotope studies of the host and gangue carbonates of Mississippi Valley-type zinc-lead deposits in the San Vicente District hosted in the Upper Triassic to Lower Jurassic dolostones of the Pucara basin (central Peru) were used to constrain models of the ore formation. A mixing model between an incoming hot saline slightly acidic radiogenic (Pb, Sr) fluid and the native formation water explains the overall isotopic variation (delta(13)C = - 11.5 to + 2.5 parts per thousand relative to PDB and delta(18)O = + 18.0 to + 24.3 parts per thousand relative to SMOW) of the carbonate generations. The dolomites formed during the main ore stage show a narrower range (delta(13)C = - 0.1 to + 1.7 parts per thousand and delta(18)O = + 18.7 to + 23.4 parts per thousand) which is explained by exchange between the mineralizing fluids and the host carbonates combined with changes in temperature and pressure. This model of fluid-rock interaction explains the pervasive alteration of the host dolomite I and precipitation of sphalerite I. The open-space filling hydrothermal white sparry dolomite and the coexisting sphalerite II formed by prolonged fluid-host dolomite interaction and limited CO2 degassing. Late void-filling dolomite III (or calcite) and the associated sphalerite III formed as the consequence of CO2 degassing and concomitant pH increase of a slightly acidic ore fluid. Widespread brecciation is associated to CO2 outgassing. Consequently, pressure variability plays a major role in the ore precipitation during the late hydrothermal events in San Vicente. The presence of native sulfur associated with extremely carbon-light calcites replacing evaporitic sulfates (e.g., delta(13)C = - 11.5 parts per thousand), altered native organic matter and heavier hydrothermal bitumen (from - 27.0 to - 23.0 parts per thousand delta(13)C) points to thermochemical reduction of sulfate and/or thiosulfate. The delta(13)C- and delta(18)O-values of the altered host dolostone and hydrothermal carbonates, and the carbon isotope composition of the associated organic matter show a strong regional homogeneity. These results coupled with the strong mineralogical and petrographic similarities of the different MVT occurrences perhaps reflects the fact that the mineralizing processes were similar in the whole San Vicente belt, suggesting the existence of a common regional mineralizing hydrothermal system with interconnected plumbing.

Metallogenic model of the Trepca Pb-Zn-Ag skarn deposit, Kosovo: Evidence from fluid inclusions, Rare Earth Elements, and stable isotope data

The Trepca Pb-Zn-Ag skarn deposit (29 Mt of ore at 3.45% Pb, 2.30% Zn, and 80 g/t Ag) is located in the Kopaonik block of the western Vardar zone, Kosovo. The mineralization, hosted by recrystallized limestone of Upper Triassic age, was structurally and lithologically controlled. Ore deposition is spatially and temporally related with the postcollisional magmatism of Oligocene age (23-26 Ma). The deposit was formed during two distinct mineralization stages: an early prograde closed-system and a later retrograde open-system stage. The prograde mineralization consisting mainly of pyroxenes (Hd(54-100)Jo(0-45)Di(0-45)) resulted from the interaction of magmatic fluids associated with Oligocene (23-26 Ma) postcollisional magmatism. Whereas there is no direct contact between magmatic rocks and the mineralization, the deposit is classified as a distal Pb-Zn-Ag skarn. Abundant pyroxene reflects low oxygen fugacity (<10(-31) bar) and anhydrous environment. Fluid inclusion data and mineral assemblage limit the prograde stage within a temperature range between 390 degrees and 475 degrees C. Formation pressure is estimated below 900 bars. Isotopic composition of aqueous fluid, inclusions hosted by hedenbergite (delta D = -108 to -130 parts per thousand; delta O-18 = 7.5-8.0 parts per thousand), Mn-enriched mineralogy and high REE content of the host carbonates at the contact with the skarn mineralization suggest that a magmatic fluid was modified during its infiltration through the country rocks. The retrograde mineral assemblage comprises ilvaite, magnetite, arsenopyrite, pyrrhotite, marcasite, pyrite, quartz, and various carbonates. Increases in oxygen and sulfur fugacities, as well as a hydrous character of mineralization, require an open-system model. The opening of the system is related to phreatomagmatic explosion and formation of the breccia. Arsenopyrite geothermometer limits the retrograde stage within the temperature range between 350 degrees and 380 degrees C and sulfur fugacity between 10(-8.8) and 10(-7.2) bars. The principal ore minerals, galena, sphalerite, pyrite, and minor chalcopyrite, were deposited from a moderately saline Ca-Na chloride fluid at around 350 degrees C. According to the isotopic composition of fluid inclusions hosted by sphalerite (delta D = -55 to -74 parts per thousand; delta O-18 = -9.6 to -13.6 parts per thousand), the fluid responsible for ore deposition was dominantly meteoric in origin. The delta S-31 values of the sulfides spanning between -5.5 and +10 parts per thousand point to a magmatic origin of sulfur. Ore deposition appears to have been largely contemporaneous with the retrograde stage of the skarn development. Postore stage accompanied the precipitation of significant amount of carbonates including the travertine deposits at the deposit surface. Mineralogical composition of travertine varies from calcite to siderite and all carbonates contain significant amounts of Mn. Decreased formation temperature and depletion in the REE content point to an influence of pH-neutralized cold ground water and dying magmatic system.

Ophiolite-related ultramafic rocks (Serpentinites) in the Caribbean region: a review of their occurrence, composition, origin, emplacements and Ni-Laterite soil formation

Ultramafic rocks, mainly serpentinized peridotites of mantle origin, are mostly associated with the ophiolites of Mesozoic age that occur in belts along three of the margins of the Caribbean plate. The most extensive exposures are in Cuba. The ultramafic-mafic association (ophiolites) were formed and emplaced in several different tectonic environments. Mineralogical studies of the ultramafic rocks and the chemistry of the associated mafic rocks indicate that most of the ultramafic-mafic associations in both the northern and southern margins of the plate were formed in arc-related environments. There is little mantle peridotite exposed in the ophiolitic associations of the west coast of Central America, in the south Caribbean in Curacao and in the Andean belts in Colombia. In these occurrences the chemistry and age of the mafic rocks indicates that this association is mainly part of the 89 Ma Caribbean plateau province. The age of the mantle peridotites and associated ophiolites is probably mainly late Jurassic or Early Cretaceous. Emplacement of the ophiolites possibly began in the Early Cretaceous in Hispaniola and Puerto Rico, but most emplacement took place in the Late Cretaceous to Eocene (e.g. Cuba). Along the northern South America plate margin, in the Caribbean mountain belt, emplacement was by major thrusting and probably was not completed until the Oligocene or even the early Miocene. Caribbean mantle peridotites, before serpentinization, were mainly harzburgites, but dunites and lherzolites are also present. In detail, the mineralogical and chemical composition varies even within one ultramafic body, reflecting melting processes and peridotite/melt interaction in the upper mantle. At least for the northern Caribbean, uplift (postemplacement tectonics) exposed the ultramafic massifs as a land surface to effective laterization in the beginning of the Miocene. Tectonic factors, determining the uplift, exposing the peridotites to weathering varied. In the northern Caribbean, in Guatemala, Jamaica, and Hispaniola, uplift occurred as a result of transpresional movement along pre-existing major faults. In Cuba, uplift occurred on a regional scale, determined by isostatic adjustment. In the south Caribbean, uplift of the Cordillera de la Costa and Serrania del Interior exposing the peridotites, also appears to be related to strike-slip movement along the El Pilar fault system. In the Caribbean, Ni-laterite deposits are currently being mined in the central Dominican Republic, eastern Cuba, northern Venezuela and northwest Colombia. Although apparently formed over ultramafic rocks of similar composition and under similar climatic conditions, the composition of the lateritic soils varies. Factors that probably determined these differences in laterite composition are geomorphology, topography, drainage and tectonics. According to the mineralogy of principal ore-bearing phases, Dominican Ni-laterite deposits are classified as the hydrous silicate-type. The main Ni-bearing minerals are hydrated Mg-Ni silicates (serpentine and ¿garnierite¿) occurring deeper in the profile (saprolite horizon). In contrast, in the deposits of eastern Cuba, the Ni and Cooccurs mainly in the limonite zone composed of Fe hydroxides and oxides as the dominant mineralogy in the upper part of the profile, and are classified as the oxide-type.

The sandstone-hosted Beverley uranium Deposit, Lake Frome Basin, South Australia: Mineralogy, geochemistry, and a time-constrained model for its genesis

The sandstone-hosted Beverley uranium deposit is located in terrestrial sediments in the Lake Frome basin in the North Flinders Ranges, South Australia. The deposit is 13 km from the U-rich Mesoproterozoic basement of the Mount Painter inlier, which is being uplifted 100 to 200 m above the basin by neotectonic activity that probably initiated in the early Pliocene. The mineralization was deposited mainly in organic matter-poor Miocene lacustrine sands and partly in the underlying reductive strata comprising organic matter-rich clays and silts. The bulk of the mineralization consists of coffinite and/or uraninite nodules, growing around Co-rich pyrite with an S isotope composition (delta S-34 = 1.0 +/- 0.3 parts per thousand), suggestive of an early diagenetic lacustrine origin. In contrast, authigenic sulfides in the bulk of the sediments have a negative S isotope signature (delta S-34 ranges from -26.2 to -35.5 parts per thousand), indicative of an origin via bacterially mediated sulfate reduction. Minor amounts of Zn-bearing native copper and native lead also support the presence of specific, reducing microenvironments in the ore zone. Small amounts of carnotite are associated with the coffinite ore and also occur beneath a paleosoil horizon overlying the uranium deposit. Provenance studies suggest that the host Miocene sediments were derived from the reworking of Early Cretaceous glacial or glaciolacustrine sediments ultimately derived from Paleozoic terranes in eastern Australia. In contrast, the overlying Pliocene strata were in part derived from the Mesoproterozoic basement inlier. Mass-balance and geochemical data confirm that granites of the Mount Painter domain were the ultimate source of U and BEE at Beverley. U-Pb dating of coffinite and carnotite suggest that the U mineralization is Pliocene (6.7-3.4 Ma). The suitability of the Beverley deposit for efficient mining via in situ leaching, and hence its economic value, are determined by the nature of the hosting sand unit, which provides the permeability and low reactivity required for high fluid flow and low chemical consumption. These favorable sedimentologic and geometrical features result from a complex conjunction of factors, including deposition in lacustrine shore environment, reworking of angular sands of glacial origin, deep Pliocene weathering, and proximity to an active fault exposing extremely U rich rocks.

Le diable et l'artiste : la littérature et la peinture symbolistes en Russie

Le diable et l'artiste est une plongée dans l'atmosphère «démoniaque » qui régnait en Russie au passage du dix-neuvième au vingtième siècle. Au moment où la Russie, tout comme l'Europe, connaît un vif engouement pour l'ésotérisme, l'occultisme et la théosophie, les écrivains et les artistes s'emparent de la figure diabolique et l'adaptent à leur époque. Après le diable grandiose et solitaire de la période romantique, les symbolistes transforment et stylisent ce personnage, l'incarnant en de, multiples avatars, tantôt majestueux, tantôt petits et mesquins. Le sentiment apocalyptique qui imprègne le tournant du siècle, bientôt confirmé par les bouleversements socio-historiques, renforce encore le mysticisme des artistes et des écrivains, qui invoquent la présence du démon pour mieux comprendre le monde. Dans cet ouvrage, Fanny Mossière montre que la représentation symboliste du diable se caractérise par un «brouillage », un flou, une indétermination : toujours ambigu, insaisissable, «autre », le démon est difficile à percevoir. C'est le cas dans deux romans essentiels pour la période symboliste, L'ange de feu de Valerij Brjusov et Un démon de petite envergure de Fedor Sologub, qui mettent respectivement en scène le personnage mi-angélique mi-démoniaque de Madiel', et nedotykomka, démon informe et inquiétant. Le Maître et Marguerite de Mihail Bulgakov, plus tardif, s'inscrit dans la lignée du mouvement artistique et esthétique symboliste, tant au niveau stylistique que pour sa démonologie débridée. Enfin, une étude de l'oeuvre picturale de Mihail Vrubel', et plus particulièrement de son Démon, complète ce «portrait du diable » à l'orée du vingtième siècle.

PHYTOAVAILABILITY OF COPPER IN INDUSTRIAL BY-PRODUCTS AND MINERAL FERTILIZERS

Alternative copper (Cu) sources could be used in fertilizer production, although the bioavailability of copper in these materials is unknown. The objective of this study was to evaluate the extractants neutral ammonium citrate (NAC), 2 % citric acid, 1 % acetic acid, 10 % HCl, 10 % H2SO4, buffer solution pH 6.0, DTPA, EDTA, water, and hot water in the quantification of available Cu content in several sources, relating them to the relative agronomic efficiency (RAE) of wheat grown in a clayey Latossolo Vermelho eutrófico (Oxisol) and Neossolo Quartzarênico (Typic Quartzipsamment). Copper was applied at the rate of 1.5 mg kg-1 as scrap slag, brass slag, Cu ore, granulated copper, and copper sulfate. The extractants 10 % HCl, 10 % H2SO4, and NAC extracted higher Cu concentrations. The RAE values of brass slag and Cu ore were similar to or higher than those of Cu sulfate and granulated Cu. Solubility in the 2nd NAC extractant, officially required for mineral fertilizers with Cu, was lower than 60 % for the scrap slag, Cu ore, and granulated copper sources. This fact indicates that adoption of the NAC extractant may be ineffective for industrial by-products, although no extractant was more efficient in predicting Cu availability for wheat fertilized with the Cu sources tested.

Magmatic-dominated fluid evolution in the Jurassic Nambija gold skarn deposits (southeastern Ecuador)

The Jurassic (approximately 145 Ma) Nambija oxidized gold skarns are hosted by the Triassic volcanosedimentary Piuntza unit in the sub-Andean zone of southeastern Ecuador. The skarns consist dominantly of granditic garnet (Ad(20-98)) with subordinate pyroxene (Di(46-92)Hd(17-42)Jo(0-19)) and epidote and are spatially associated with porphyritic quartz-diorite to granodiorite intrusions. Endoskarn is developed at the intrusion margins and grades inwards into a potassic alteration zone. Exoskarn has an outer K- and Na-enriched zone in the volcanosedimentary unit. Gold mineralization is associated with the weakly developed retrograde alteration of the exoskarn and occurs mainly in sulfide-poor vugs and milky quartz veins and veinlets in association with hematite. Fluid inclusion data for the main part of the prograde stage indicate the coexistence of high-temperature (500A degrees C to > 600A degrees C), high-salinity (up to 65 wt.% eq. NaCl), and moderate- to low-salinity aqueous-carbonic fluids interpreted to have been trapped at pressures around 100-120 MPa, corresponding to about 4-km depth. Lower-temperature (510-300A degrees C) and moderate- to low-salinity (23-2 wt.% eq. NaCl) aqueous fluids are recorded in garnet and epidote of the end of the prograde stage. The microthermometric data (Th from 513A degrees C to 318A degrees C and salinity from 1.0 to 23 wt.% eq. NaCl) and delta(18)O values between 6.2aEuro degrees and 11.5aEuro degrees for gold-bearing milky quartz from the retrograde stage suggest that the ore-forming fluid was dominantly magmatic. Pressures during the early retrograde stage were in the range of 50-100 MPa, in line with the evidence for CO(2) effervescence and probable local boiling. The dominance of magmatic low-saline to moderately saline oxidizing fluids during the retrograde stage is consistent with the depth of the skarn system, which could have delayed the ingression of external fluids until relatively low temperatures were reached. The resulting low water-to-rock ratios explain the weak retrograde alteration and the compositional variability of chlorite, essentially controlled by host rock compositions. Gold was precipitated at this stage as a result of cooling and pH increase related to CO(2) effervescence, which both result in destabilization of gold-bearing chloride complexes. Significant ingression of external fluids took place after gold deposition only, as recorded by delta(18)O values of 0.4aEuro degrees to 6.2aEuro degrees for fluids depositing quartz (below 350A degrees C) in sulfide-rich barren veins. Low-temperature (< 300A degrees C) meteoric fluids (delta(18)O(water) between -10.0aEuro degrees and -2.0aEuro degrees) are responsible for the precipitation of late comb quartz and calcite in cavities and veins and indicate mixing with cooler fluids of higher salinities (about 100A degrees C and 25 wt.% eq. NaCl). The latter are similar to low-temperature fluids (202-74.5A degrees C) with delta(18)O values of -0.5aEuro degrees to 3.1aEuro degrees and salinities in the range of 21.1 to 17.3 wt.% eq. CaCl(2), trapped in calcite of late veins and interpreted as basinal brines. Nambija represents a deep equivalent of the oxidized gold skarn class, the presence of CO(2) in the fluids being partly a consequence of the relatively deep setting at about 4-km depth. As in other Au-bearing skarn deposits, not only the prograde stage but also the gold-precipitating retrograde stage is dominated by fluids of magmatic origin.

Origin of siderite mineralisation in Petrova and Trgovska Gora Mts., NW Dinarides

The Petrova and Trgovska Gora Mts. (Gora=Mountain) are Variscan basement units incorporated into the northwestern Dinarides during the Alpine orogeny. They host numerous siderite-quartz-polysulphide, siderite-chalcopyrite, siderite-galena and barite veins, as well as stratabound hydrothermal-replacement ankerite bodies within carbonates in non-metamorphosed, flysch-like Permo-Carboniferous sequences. The deposits have been mined for Cu, Pb, Ag and Fe ores since Medieval times. Fluid inclusion studies of quartz from siderite-polysulphide-quartz and barite veins of both regions have shown the presence of primary aqueous NaCl-CaCl(2)+/- MgCl(2)-H(2)O +/- CO(2) inclusions. The quartz-sulphide stage of both regions show variable salinities; 2.7-26.2 wt% NaCl eq. for the Trgovska Gora region and 3.4-23.4 wt% NaCl eq. for the Petrova gora region, and similar homogenisation temperatures (100-230A degrees C). Finally, barite is precipitated from low salinity-low temperature solutions (3.7-15.8 wt % NaCl equ. and 115-145A degrees C). P-t conditions estimated via isochore construction yield formation temperatures between 180-250A degrees C for the quartz-sulphide stage and 160-180A degrees C for the barite stage, using a maximum lithostatic pressure of 1 kbar (cc. 3 km of overburden). The sulphur isotope composition of barite from both deposits indicates the involvement of Permian seawater in ore fluids. This is supported by the elevated bromium content of the fluid inclusion leachates (120-660 ppm in quartz, 420-960 ppm in barite) with respect to the seawater, indicating evaporated seawater as the major portion of the ore-forming fluids. Variable sulphur isotope compositions of galena, pyrite and chalcopyrite, between -3.2 and +2.7aEuro degrees, are interpreted as a product of incomplete thermal reduction of the Permian marine sulphate mixed with organically- and pyrite-bound sulphur from the host sedimentary rocks. Ore-forming fluids are interpreted as deep-circulating fluids derived primarily from evaporated Permian seawater and later modified by interaction with the Variscan basement rocks. (40)Ar/(39)Ar data of the detrital mica from the host rocks yielded the Variscan age overprinted by an Early Permian tectonothermal event dated at 266-274 Ma. These ages are interpreted as those reflecting hydrothermal activity correlated with an incipient intracontinental rifting in the Tethyan domain. Nevertheless, 75 Ma recorded at a fine-grained sericite sample from the alteration zone is interpreted as a result of later resetting of white mica during Campanian opening/closure of the Sava back arc in the neighbouring Sava suture zone (Ustaszewski et al. 2008).

Le paradoxe tibétain : Théodore Pavie et les explorateurs du Tibet

Si le Tibet figure en marge des voyages et de l'oeuvre de Théodore Pavie, il occupe pourtant une position-clé, quoique déconsidérée, dans le programme scientifique de l'auteur. L'orientaliste - indianiste et sinologue - s'est rendu en Inde et en Chine lors de son voyage de 1839, mais non au Tibet, alors encore largement inexploré. De surcroît, alors que Pavie succède à Eugène Burnouf, auteur éminent de l'Introduction au bouddhisme indien (1844), à la chaire d'études indiennes du Collège de France, ce n'est pas lui mais son condisciple Philippe-Edouard Foucaux qui prendra en charge l'enseignement du tibétain dans les milieux orientalistes parisiens. Dès lors, en quoi le nom de Pavie se rapporte-t-il à l'histoire des savoirs et des représentations du Tibet ?A Calcutta, notre voyageur fait la rencontre d'Alexandre Csoma de Kőrös, savant hongrois fondateur des études tibétaines. A son retour en France, alors même que l'on apprend en Europe l'exploit du père Huc, lequel missionnaire vient de pénétrer à Lhassa, Pavie rédige un article dans la Revue des Deux Mondes sur « Le Thibet et les études thibétaines » (1847). Cet article, pétri par un souffle romantique grandiose, articule savoirs et imaginaire sur le Tibet. Les Tibétains, sauvages et primitifs, à l'image de leur territoire, sont présentés comme les héritiers historiques des civilisations indienne et chinoise. Le Tibet apparaît dès lors comme le musée pétrifié du bouddhisme originel, que le savant peut reconstituer sous les traits - à ses yeux dégénérés - du « lamaïsme », et, en premier lieu, à travers les livres innombrables des bibliothèques des monastères tibétains - attirant sans le savoir l'attention du public français sur l'une des plus grandes littératures du monde. Tout en balisant un nouveau domaine d'études « interdisciplinaire » s'ouvrant à l'orientalisme, Pavie n'en vient-il pas à formuler ce que l'on pourrait appeler un paradoxe tibétain ? Comment le Tibet, isolé par-delà les plus imposantes chaînes de montagne du globe, peut-il être le dépositaire d'une des plus grandes civilisations de l'histoire humaine ? A l'orée de la grande période d'exploration du Tibet, l'orientaliste ne consacre-t-il pas une vision du Tibet qui fera fortune chez les voyageurs français de la seconde moitié du XIXe siècle ? Examiner ce pan de la tibétologie française naissante amène à croiser différentes figures de savants et d'explorateurs, en vue de dégager les processus par lesquels savoirs et représentations liés au Tibet se sont constitués à la fin du XIXe siècle.

The correct name, species diagnosis, and distribution of the Sicilian shrew

New karyological and morphological data show that Sicily, the Egadi Islands, Malta and Gozo are (ore were) inhabited by a particular species of Crocidura, for which the name Crocidura sicula Miller, 1901 is available. The species is briefly diagnosed and described and a new key to the European species of Crocidura is presented

Long diagnostic delay in Crohn's disease is associated with complicated disease course and increased operation rate

Background and Aims: The impact of d iagnostic delay ( a period from appearance of f irst s ymptoms t o diagnosis) o n the clinical c ourse o f Crohn's disease (CD) i s unknown. W e examined whether length of d iagnostic delay a ffects d isease outcome. Methods: Data from the Swiss IBD cohort study were analyzed. T he frequencies of o ccurrence of b owel s tenoses, internal fistulas, perianal f istulas, and CD-related surgery at distinct i ntervals a fter C D diagnosis (0 - < 2 , 2 - < 6,  6 years) were c ompared f or g roups o f patients w ith different length of d iagnostic delay. Results: T he data from a g roup o f 200 CD patients with long diagnostic delay (> 24 months, 76th - 100th p ercentile) were c ompared to t hose from a group of 4 61 patients with a short diagnostic delay ( within 9 months, 1st - 50th p ercentile). T reatment r egimens d id n ot d iffer between t he two groups. Two years following diagnosis, p atients with long diagnostic delay presented more frequently with bowel stenoses (25% vs. 13.1%, p = 0.044), internal fistulas (10% vs. 2%, p = 0.018), perianal f istulas ( 20% vs. 8 .1%, p = 0.023) a nd more frequently underwent intestinal surgery (15% vs. 5 .1%, p = 0.024) t han patients with short diagnostic delay. Intestinal surgery was a lso m ore frequently p erformed  6 y ears after diagnosis in t he group with long d iagnostic delay ( 56.2% vs. 42.3%, p = 0.005) w hen compared to t he g roup with short diagnostic delay. Conclusions: L ong diagnostic delay i s associated with worse o utcome c haracterized by t he development o f increased bowel damage, n ecessitating more frequently operations in t he years following CD d iagnosis. Efforts should be undertaken to shorten the diagnostic delay.