U ovom radu istraživan je serpentinit s nalazišta na Banovini u Hrvatskoj. U toj mineralnoj sirovini prevladavajući mineral je antigorit. Dilatacijska krivulja ukazuje da je prva kontrakcija uzorka ...uzrokovana dehidratacijom antigorita na približno 660°C. Nasuprot tome, na drugu kontrakciju uzorka koja počinje pri približno 860°C utječe stvaranje olivina. Morfologija serpentinita prije i poslije termičke obradbe promatrana je optičkim mikroskopom. Izgled serpentinita prije termičke obradbe karakteriziran je uključcima olivina kao primarnog minerala zaostalog u procesu serpentinizacije. Izgled serpentinita poslije termičke obradbe promijenio se uslijed eliminacije vode. Prvo termički obrađen te potom mljeven serpentinit ima bolje karakteristike od prvo mljevenog, a potom termički obrađenog serpentinita.
O Morro do Níquel, maciço serpentinítico situado na extensão sul da Faixa Brasília Meridional, no contexto da Nappe de Passos, foi objeto de estudo mineralógico e textural detalhado, desenvolvido com ...base em testemunho de sondagem, visando caracterizar os litotipos ali presentes. Esse corpo apresenta formato elipsoidal, com dimensões de 400 x 800 metros e espessura superior a 300 metros, constituído, unicamente, por serpentinito. Esses serpentinitos apresentam predominância de texturas mesh, mesh-ribbon e ribbon, constituídas de lizardita/crisotilo e pseudomorfos que remetem a cristais reliquiares de olivina. A homogeneidade das amostras estudadas indica que o protólito potencialmente era composto de rocha com textura granular, granulação média/grossa (>0,5cm) e mineralogia constante, correspondendo, possivelmente, a um dunito. Nesse maciço são descritas condições indicativas de dois eventos metamórficos, um mais antigo que se desenvolveu em fácies anfibolito, e um mais jovem, em fácies prehnita-pumpellyita, mas que preservou, parcialmente, feições do evento pretérito. A presença de awaruita e heazlewoodita descreve uma condição de serpentinização em condições de baixa fugacidade de O2 e S2. A análise petrográfica, litológica e metamórfica aponta que esse corpo guarda características distintas dos serpentinitos do Greenstone Belt Morro do Ferro, unidade metavulcanossedimentar arqueana à qual é atualmente associado.
The use of alternative sources for fertilization in agriculture is being increasingly exploited by man because of the shortage of the finite sources of minerals used today Products such as cake ...castor bean and serpentinite silicate, may be viable sources for use in agriculture. Thus, the aim of this study was to evaluate the contents and accumulation of N, P, K, Ca and Mg in the culture of crambe, as well as their production in line with fertilization cake castor bean PDS and silicate serpentinite. The experiment was conducted in a greenhouse in a completely randomized design with seven doses of cake castor bean PDS and two doses of serpentinite silicate (with and without elemental sulfur), totaling 21 treatments. We used doses of 0.0, 0.5, 1, 2, 4, 6 and 8t ha.sup.-1 of cake castor bean PDS (equivalent to the application of 0, 15, 30, 60, 120 and 240kg ha.sup.-1 of N) and the doses of serpentinite silicate 0 and 1t ha.sup.-1 for with and without sulfur The application of serpentinite silicate without sulfur increased the content and nutrient content of N, P, K, Ca and Mg and crambe seed production. The use of cake castor bean PDS as organic fertilizer increased the growth and development of crambe. A dose of 8t ha.sup.-1 of castor bean PDS was the most suitable for the fertilization of the crop crambe.
Les malformations congénitales des pieds de l’enfant sont des déformations peu ou pas réductibles à la naissance. Elles sont à distinguer des malpositions qui, elles, sont des déformations bien ...réductibles par mobilisations et stimulations motrices, comme le métatarsus adductus ou le pied calcanéus. Ces dernières sont d’origine positionnelle et représentent un motif fréquent d’inquiétude parentale. Elles nécessitent peu ou pas de traitement, car leur évolution est le plus souvent spontanément favorable. Les malformations se distinguent par une anomalie de développement fœtale précoce, une réductibilité incomplète à la naissance et la nécessité de traitement, afin d’assurer la possibilité d’un chaussage confortable et indolore. La plus fréquente des malformations est le pied bot varus équin, dont la prise en charge orthopédique commence dans la première semaine de vie. Le traitement chirurgical est de plus en plus rare et différé. Les autres malformations visibles à la naissance, touchant l’arrière- et le médio-pied sont beaucoup plus rares et comprennent le pied convexe et le pied serpentin. La prise en charge est initialement orthopédique, mais nécessite souvent un geste chirurgical à l’âge de la marche. Les malformations des orteils comprennent les syndactylies (défaut de segmentation), les clinodactylies (désaxation des orteils), les brachydactylies (défaut de longueur d’un rayon), les agénésies ou ectromélies (absence d’un ou plusieurs rayons), les polydactylies (excès de nombre des orteils), les macrodactylies (excès de volume des orteils). Ces malformations peuvent être combinées dans différents syndromes et justifient d’un traitement chirurgical ultérieur si le chaussage est gêné. Le pédiatre a besoin de savoir reconnaître ces différentes malformations, lui permettant ainsi d’orienter l’enfant, de manière adéquate, vers un chirurgien orthopédique pédiatrique qui débutera un traitement, dans un délai dépendant du type d’anomalie.
► Investigation of zircon in jadeite–quartz rocks from the Kanto Mountains, Japan. ► Jadeite–quartz rocks formed contemporaneously with the Jurassic accretionary complex. ► HFSE concentrated in ...jadeite–quartz rock prior to the fluid moving up into the mantle wedge. ► Jadeite-bearing rocks may be abundant in or above subducted slab.
This paper reports the results of U–Pb dating and REE (rare earth element) analysis of zircons separated from jadeite–quartz rocks within serpentinite mélanges in the Yorii area of the Kanto Mountains, Japan. These rocks contain jadeite, albite, and quartz, with minor aegirine–augite, zircon, monazite, thorite, allanite, and titanite. Mineral textures provide evidence of a jadeite+quartz=albite reaction during formation of these jadeite–quartz rocks. Zircon crystals separated from the jadeite–quartz rocks can be split into two distinct types, here named Types I and II, based on their morphology and REE concentrations. Type I zircons are prismatic and have fluid, jadeite, quartz, and albite inclusions. Those show positive Ce and negative Eu anomalies and HREE (heavy rare earth element) enriched chondrite normalized REE patterns and have higher REE concentrations than those generally found in magmatic zircons. Type I zircons would have precipitated from a fluid. Mineralogical observation provides that Type I zircon crystallized at the same timing of the formation of the jadeite–quartz rocks. Type II zircons are porous and have REE patterns indicative of a hydrothermal zircon. Both types of zircons are fluid-related. Type I zircons yield U–Pb ages of 162.2±0.6Ma, with an MSWD (mean square weighted deviation) of 1.4. At this time, Japan was still a part of the eastern margin of the Asian continent, with the subduction of the oceanic paleo-Pacific Plate leading to the formation of the Jurassic Mino–Tanba–Chichibu accretionary complex in Japan. The age data indicate that the jadeite–quartz rocks formed in a deep subduction zone environment at the same time as the formation of the Jurassic accretionary complex in a shallower near-trench subduction zone environment. The jadeite–quartz rocks contain high concentrations of Zr and Nb, with low LILE (large ion lithophile elements) concentrations, suggesting that the HFSE (high field strength elements) can be concentrated into jadeite–quartz rocks prior to a fluid moving up into the mantle wedge. Typical arc volcanic rocks are depleted in the HFSE, suggesting that the high HFSE concentrations within jadeite–quartz rocks are consistent with fluids being stripped of their HFSE prior to interaction with mantle material during the formation of arc magmas. Although these jadeite-bearing rocks are rare occurrences on the surface exposure, they could be abundant in or above subducted slabs.
The problems of the stability of the mineral-bearing structure ST2 at 560 m of depth in the east zone of Bou-azzer mine disturbs the advance of the exploitation. The geological and structural study ...based on field observations and the analysis of core drilling shows the presence of altered and fractured diorite surmounted by cobalt mineralization. Based on the empirical methods of Barton (Q-system) and Bieniawski (RMR) the bed rock is classified as poor quality. The analytical study made it possible to dimension supporting by bow-pieces and bolting. The existence of several types of discontinuities (fault, diaclases and joints) has made the realization of numerical simulation by the finite elements method very difficult. These discontinuities create a network of natural fractures which cut out the blocks in various forms likely to be detached or slip into the excavation, thus encouraging the infiltration of water creating pressure on the massif. The classical studies show their limits in practice for installation of supporting because they must take into account the characteristics of discontinuities. Hence a structural analysis of the massif is essential. The cracking survey of ST2 at 560 m of depth in the east zone of Bou-azzer mine at 560m of depth, and their processing by the DIPS software, showed the existence of three main families of discontinuity NW-SE with a dip of 75SW, NS subverticale and NE-SW with a dip of 57NW, and two families of minor joints NW-SE and NE-SW with successive dips of 40SW and 75SE. The analysis of fracturing surveys allowed us to evaluate the risks of falling blocks and the families of discontinuity responsible for them, and to limit the zones presenting a risk of slip and the families responsible for them. The importance of this study is of knowing how and where to put supporting to be opposed to the risk of fall and tilting of the blocks, caused by the network of discontinuities of the massif. Les problèmes de la stabilité de la mine de Bou-azzer zone Est au niveau de la structure minéralisée ST2 à 560 m de profondeur perturbe l’avancement de l’exploitation. L’étude géologique et structurale basées sur les observations de terrain et l’analyse des sondages carottés, montre la présence de la diorite altérée et fracturée surmontée de la minéralisation de Cobalt constituée de Skuttérudite et la Safflorite, et parfois Loellingite qui entre en contact avec la serpentine. En se basant sur les méthodes empiriques Barton (Qsystème), ou Bieniawski (RMR) le terrain est classé de qualité médiocre, l’étude analytique a permis de dimensionner le soutènement par cintres et boulons d’encrages. L’existence de plusieurs type de discontinuités (faille, diaclases et joints) ont rendu la réalisation de simulation numérique par la méthode des éléments finis très difficile, ces discontinuités créent un réseau de fractures naturelles qui découpent les blocs en différentes formes susceptibles de se détacher ou de glisser dans l’excavation, favorisant ainsi l’infiltration des eaux créant une pression sur le massif. Les études classiques entamées précédemment montrent leurs limites en pratique pour la pose du soutènement, parce qu’ils doivent prendre en considération les caractéristiques des discontinuités. D’où une analyse structurale du massif s’avère indispensable. Les levées de la fissuration au niveau -560 dans la ST2 de la mine de Bou-azzer Est, et leurs traitement par le logiciel DIPS, a montré l’existence de trois familles de discontinuité principales NW-SE avec un pendage de 75SW, N-S subverticale et NE-SW avec un pendage de 57NW et deux familles de joints mineurs NW-SE et NE-SW avec des pendages successive de 40SW et 75SE. Le traitement des relevées de la fracturation nous a permis d’évaluer les risques de chute de blocs et les familles de discontinuité qui en sont responsables, et de limiter les zones présentant un risque de glissement et les familles qui en sont responsable. L’importance de cette étude est de savoir comment et où mettre le soutènement pour s’opposer au risque de chute et de basculement des blocs, provoqué par le réseau de discontinuité du massif.
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