Journal articles: 'Mélange fluide'

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Fleury, F., and J. C. Nedelec. "Étude asymptotique des phénomènes acoustiques dans un mélange fluide-solide thermoélastique." Mathematical Methods in the Applied Sciences 7, no. 1 (1985): 154–69. http://dx.doi.org/10.1002/mma.1670070110.

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Chaumont, Diane, André G. Roy, and François Courchesne. "Traçage minéralogique de l’origine des sédiments aux confluents de cours d’eau." Géographie physique et Quaternaire 48, no. 2 (November 30, 2007): 195–205. http://dx.doi.org/10.7202/032996ar.

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RÉSUMÉTraçage minéralogique de l'origine des sédiments aux confluents de cours d'eau. La dynamique sédimentaire des confluents de cours d'eau peut s'étudier par l'intermédiaire de traceurs marquant l'origine des particules. La connaissance de la source sédimentaire est essentielle pour comprendre les processus de mélange des sédiments du lit et établir des relations causales entre les sources de contamination et la dynamique des sites contaminés liés à l'arrivée d'un tributaire. On a examiné les particules du lit d'un confluent naturel sablonneux où la minéralogie des sédiments composant les bassins-versants est différenciée. En raison de leurs forme et densité, les feldspaths K s'avèrent des traceurs efficaces et indiquent qu'à la jonction étudiée le mélange des apports sédimentaires est presque complété à une distance de mélange de 2,1 (distance à partir de l'apex/largeur du confluent). Par contre, les micas et le pourcentage de minéraux lourds, sensibles au tri hydraulique, ne révèlent pas la provenance des particules. La méthode a aussi été employée pour déterminer le patron de dispersion des particules à un confluent du Saint-Laurent. Ici la minéralogie des particules diffère peu entre les bassins-versants. Toutefois, les variations spatiales du pourcentage de minéraux lourds sont directement liées à la morphologie du lit caractérisée par un banc d'accumulation se terminant par un abrupt à l'entrée du tributaire. Les faibles teneurs en minéraux lourds sur la pente de l'abrupt démontrent que le fluide est peu compétent à l'abri de la construction sédimentaire. Par contre, à son pied et à son sommet, le fluide effectue un tri hydraulique efficace, ce qui entraîne une concentration des particules lourdes. Ces variations des teneurs en minéraux lourds sont indicatrices du tri hydraulique plutôt que de la source sédimentaire.

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Valette, Rudy, Julien Bruchon, Hugues Digonnet, Patrice Laure, Mathilde Lebœuf, Luisa Silva, Bruno Vergnes, and Thierry Coupez. "Méthodes d'interaction fluide-structure pour la simulation multi-échelles des procédés de mélange." Mécanique & Industries 8, no. 3 (May 2007): 251–58. http://dx.doi.org/10.1051/meca:2007046.

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Belasri, Ahmed, Wafà Benstâali, and Hafid Haffaf. "Etude de l’énergie d’excitation du xénon dans une cellule d’écran a plasma; contribution a l’amélioration de l’efficacité lumineuse." Journal of Renewable Energies 6, no. 1 (June 30, 2003): 35–43. http://dx.doi.org/10.54966/jreen.v6i1.959.

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Les panneaux à plasma (PAP) sont une des principales technologies pour les écrans plats de haute résolution. C’est la raison pour laquelle un intérêt remarquable a était porté à l’amélioration de leur luminosité, leur duré de vie et leur efficacité qui est relativement faible; de l’ordre de 1 lm/W. Le présent travail est une contribution à l’étude d’une décharge à barrière diélectrique dans une cellule d’écran à plasma. Il est basé sur un modèle fluide bidimensionnel. Ce modèle permet de montrer la répartition de l’énergie dissipée dans l’excitation du xénon à travers la cellule. Il permet également de voir l'effet de la pression et du pourcentage du mélange de gaz (Xe_Ne) sur l’efficacité de la décharge à exciter les atomes de xénon dans un panneau à plasma de géométrie coplanaire.

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Laïdi, Maamar, and Salah Hanini. "Approche neuronale pour l’estimation des transferts thermiques dans un fluide frigoporteur diphasique." Journal of Renewable Energies 15, no. 3 (October 23, 2023): 513–20. http://dx.doi.org/10.54966/jreen.v15i3.340.

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La propriété associative des réseaux neurologiques artificiels et de leur capacité inhérente d’apprendre et identifier des rapports fortement non linéaires et complexes, les trouve idéalement convenus à une étendue des applications large dans le domaine du froid direct et indirect. Cet article traite les applications potentielles des réseaux neurones artificiels dans la particularité des problèmes thermiques soulevés par l’utilisation des fluides frigoporteurs diphasiques, tels que les coulis de glace (mélange de solutions binaires aqueuses et de cristaux de glace) dans les installations de distribution du froid. L’utilisation de ce type d’installation permet de diminuer, les quantités des fluides frigorigènes traditionnels, ainsi que les problèmes qu’ils engendrent, de réduire les volumes de stockage et les consommations d’électricité. La stratégie d’obtention du RN s'articule sur l'élaboration d'un programme sur MATLAB, comportant plusieurs boucles où on fait varier les algorithmes d’apprentissages, les fonctions d’activations, le nombre de couches cachées et le nombre de neurones dans chaque couche, afin de minimiser la fonction du coût sous contrainte d’une erreur relative fixée. Le modèle neuronal conçu a permis d’une part de reproduire avec une très bonne précision les données expérimentales tirées directement de littérature et d’autre part une estimation meilleure et plus précise des valeurs calculées par rapport aux modèles classiques (basé sur la formulation générale de la méthode enthalpique) des transferts thermiques dans le cas des solutions binaires dispersées sous forme d’émulsions ou de mini-émulsions subissant un changement de phase tirées directement de littérature.

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Soudani, Azeddine, Saadi Bougoul, and Jean-Luc Harion. "Réduction des étalonnages multiples en mesures simultanées dans une couche limite turbulente d'un mélange air - hélium." Journal of Renewable Energies 6, no. 2 (December 31, 2003): 77–94. http://dx.doi.org/10.54966/jreen.v6i2.963.

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Les mesures simultanées par thermo-anémométrie de plusieurs grandeurs physiques d'un fluide en écoulement turbulent, nécessite l'emploi d'autant de sondes qu'il y a de variables. Un étalonnage est préalable à toute utilisation de ces capteurs pour des mesures. Cet étalonnage est fondé sur des lois d'ajustement, réalisées généralement par des méthodes classiques d'interpolation linéaire, des régressions polynomiales, des fonctions splines ou encore par des réseaux de neurones artificiels. Il permet d'établir le lien univoque entre les sorties de ces capteurs, données sous forme de tensions, et les paramètres physiques de l'écoulement à mesurer. Suivant la forme du réseau d'étalonnage obtenue, la précision de ces méthodes peut être extrêmement sensible aux degrés des polynômes d'ajustement et peut présenter ainsi des erreurs importantes d'interpolation. Il est donc nécessaire de tester systématiquement les paramètres d'ajustement pour chaque application. On montre à travers cette étude que, les méthodes de génération de grilles cartésiennes et de dépouillement de mesures, utilisant des régressions polynomiales et des interpolations linéaires, sont beaucoup moins précises que celles utilisant les fonctions splines et les réseaux de neurones artificiels. Les résultats obtenus montrent aussi que l'utilisation d'une surchauffe plus forte pour l'élément amont que l'élément aval de la sonde apporte, en général, une meilleure précision lors de la génération des grilles.

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Dagenais, Diane. "Tensions autour de l’enseignement des littératies plurielles en milieu minoritaire." Éducation et francophonie 45, no. 2 (February 27, 2018): 5–21. http://dx.doi.org/10.7202/1043526ar.

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Le rapport de force entre les langues est devenu évident lors de l’adoption d’une innovation pédagogique visant le développement des littératies plurielles dans une classe du primaire en milieu francophone minoritaire. La titulaire de classe et l’enseignante d’anglais langue seconde ont collaboré dans des activités de production d’histoires bilingues à l’aide de l’outil numérique ScribJab. Les interactions dans cette classe ont été observées, photographiées et filmées dans une étude ethnographique pendant la production des histoires et les élèves et les enseignantes ont été interviewés sur leurs réactions à l’innovation. L’étude s’appuie sur les recherches qui révèlent la nature flexible et fluide des littératies plurielles, lesquelles sont constituées d’un mélange de codes, de variétés linguistiques et de modes d’expression. Les discussions théoriques sur les liens entre la langue et le pouvoir ainsi que les écrits sur le plurilinguisme, les littératies plurielles, la multimodalité et les politiques linguistiques ont aussi enrichi ce travail. Nous proposons dans cet article un récit ethnographique sur les tensions et les contradictions provoquées par la cohabitation des langues, traditionnellement séparées, durant les activités de production bilingue en contexte scolaire minoritaire.

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Jarmołowicz-Szulc, Katarzyna, and Leszek Jankowski. "Interpretation of Mineralization in the Western Carpathians (Polish Segment)—A Tectonic Mélange Approach." Minerals 11, no. 11 (October 22, 2021): 1171. http://dx.doi.org/10.3390/min11111171.

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Quartz, carbonates and other minerals as e.g., realgar are present in veins and caverns in sedimentary rocks in the Western Carpathians. In the Polish segment, they have been characterized from the mineralogical, petrologic, and geochemical points of view, as well as fluid inclusions. Their characters are discussed from perspective of a description of particular types of chaotic complexes—the tectonic mélange zones, distinguished in the Western Carpathian area over the last two decades. The mélange zones are considered to be geochemical systems open to fluid flow, a site for mineral crystallization and/or migration zones of hydrocarbons and mineralized waters. In this context the tectonic mélange in the Jabłonki/Rabe vicinity (SE Poland, the Bieszczady region) in comparison to that of the Mszana Dolna tectonic window area are proposed as the examples. The trapping conditions of fluids (brine and methane) in the minerals in the mélange zones appear to have been 180–205 °C and ~550–570 bars, and 220 °C and 500 bars for calcite and quartz, respectively. The general trend of the increase in temperatures and pressures from west towards east and south-east in the mélange zones points to an increase in the degree of exhumation of different parts of the Carpathians.

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Liu, Xinyu, Min Zeng, Chenwei Li, Si Chen, and Tianyuan Li. "Source and Migration of Fluids in a Meso-Tethyan Subduction Zone: Fluid Inclusion Study of Syn-Mélange Veins from the Mugagangri Accretionary Complex." Minerals 13, no. 9 (September 12, 2023): 1196. http://dx.doi.org/10.3390/min13091196.

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The Mugagangri Group (MG), located at the southern margin of the Qiangtang terrane in Tibet, is a crucial research target for understanding the subduction and accretion history of the Meso-Tethys Ocean. Extensional crack-seal veins restricted within sandstone blocks from the broken formation in the MG (Gaize) formed synchronously in the mélange formation. The primary inclusions trapped in the veins recorded multiple pieces of information during the formation of the accretionary wedge. To precisely constrain the MG subduction–accretion processes, we investigated the trapping temperature, salinity, density, and composition of the fluid inclusions within the crack-seal veins derived from the broken formation in the MG (Gaize). The primary inclusions indicate that the crack was sealed at ~151–178 °C. The salinity of the primary inclusions exhibited a well-defined average of 3.3 ± 0.7 wt% NaCl equivalent, slightly lower than the average of seawater (3.5 wt%). There were no nonpolar gases, and only H2O (low salinity) was detectable in the primary inclusions. These characteristics suggest that the syn-mélange fluids were a type of pore fluid in the shallow subduction zone, with the principal source being pore water from sediments overlying the oceanic crust. Because of mineral dehydration and compaction, the pore fluids became more diluted with H2O and fluid overpressure owing to a pore fluid pressure that was greater than the hydrostatic pressure. Subsequently, the creation of cracks through hydraulic fracturing provided a novel pathway for the flow of fluids which, in turn, contributed to the décollement step-down and underthrusting processes. These fractures acted as conduits for fluid movement and played a crucial role in facilitating these peculiar occurrences of quartz veins. The depth (~5 km) and temperature estimates of the fluid expulsion align with the conditions of the décollement step-down, thereby leading to the trapping of fluids within the sandstone blocks and their subsequent underplating to the accretionary complex. In our preferred model, such syn-mélange fluids have the potential to provide valuable constraints on the subduction–accretion processes occurring in other accretionary complexes.

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Slovenec, Damir, Boško Lugović, and Irena Vlahović. "Geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the NW External-Internal Dinarides junction (Croatia)." Geologica Carpathica 61, no. 4 (August 1, 2010): 273–92. http://dx.doi.org/10.2478/v10096-010-0016-1.

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Geochemistry, petrology and tectonomagmatic significance of basaltic rocks from the ophiolite mélange at the NW External-Internal Dinarides junction (Croatia)At the NW inflexion of the Sava-Vardar Suture Zone ophiolite mélanges, known as the Kalnik Unit, form the surface of the slopes of several Pannonian inselbergs in the SW Zagorje-Mid-Transdanubian Zone. The Mt Samoborska Gora ophiolite mélange, thought to be a part of the Kalnik Unit, forms a separate sector obducted directly onto Dinaric Triassic carbonate sediments. Basaltic rocks, the only magmatic rocks incorporated in the mélange, include Middle-Triassic (Illyrian-Fassanian) alkali within-plate basalts and Middle Jurassic (uppermost Bathonian-Lower Callovian) tholeiitic basalts. The latter sporadically constitute composite olistoliths, and are geochemically divided into N-MORB-like (high-Ti basalts) and transitional MORB/IAT (medium-Ti basalts). These geochemically different rocks suggest crystallization at various tectonomagmatic settings, which is also indicated by the rock paragenesis and host clinopyroxene compositions. Alkali basalts reflect melts derived from an OIB-type enriched mantle source [Ti/V= 62.2-82.4; (La/Lu)cn= 6.4-12.8] with Nd-Sr isotope signatures close resembling the Bulk Earth [εNd(T=235 Ma)= + 1.6 to + 2.5]. They are recognized as preophiolite continental rift basin volcanic rocks that closely predate the opening of the Repno oceanic domain (ROD) of the Meliata-Maliac ocean system. The high-Ti and medium-Ti basalts from composite blocks derived from a similar depleted mantle source (εNd(T=165 Ma) = + 6.01 vs. + 6.35) succesively metasomatized by expulsion of fluids from a subducting slab leading to a more pronounced subduction signature in the latter [Ti/V=31.6-44.8 and (Nb/La)n=0.67-0.90 vs. Ti/V=21.5-33.9 and (Nb/La)n=0.32-0.49]. These composite blocks indicate crust formation in an extensional basin spreading over the still active subducting ridge. The majority of high-Ti basalts may represent the fragments of older crust formed at a spreading ridge and incorporated in the mélange of the accretionary wedge formed in the proto-arc-fore-arc region. The Mt Samoborska Gora ophiolite mélange represents the trailing edge of the Kalnik Unit as a discrete sector that records the shortest stage of tectonomagmatic evolution related to intraoceanic subduction in the ROD.

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Wu, Fei, Simon Turner, and Bruce F. Schaefer. "Mélange versus fluid and melt enrichment of subarc mantle: A novel test using barium isotopes in the Tonga-Kermadec arc." Geology 48, no. 11 (June 25, 2020): 1053–57. http://dx.doi.org/10.1130/g47549.1.

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Abstract In the past few years, the so-called mélange model has been offered as an alternative to the long-standing model of enrichment of the subarc mantle by separate additions of fluid and sediment components from the subducting plate. In the mélange model, components from the subducting plate become physically mixed at the slab-mantle interface. Partial melting of the peridotite subsequently occurs after being hybridized by the mélange material that diapirically rises into hotter portions of the wedge. Here, we present the first Ba isotope study of lavas from the Tonga-Kermadec arc (southwest Pacific Ocean) and show that Ba isotopes distinguish between fluid and melt derived from different subducted components. This provides fresh constraints on the debate. Remarkable along-strike Ba isotope variations were observed and are best explained by contributions from variable proportions of sediment and altered oceanic crust (AOC) fluid from the subducting plate. Combined Ba-Sr-Pb isotope relationships indicate that sediment melt and AOC fluid were added to the source of the arc lavas separately at different times. This is inconsistent with the mélange model, at least in this arc.

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Khedr, Mohamed Zaki, Gehad M. Saleh, Khaled M. Abdelfadil, Eiichi Takazawa, Kamal Abdelrahman, Akihiro Tamura, and Shaimaa Ali El-Shafei. "The Geology and Mineral Chemistry of Beryl Mineralization, South Eastern Desert, Egypt: A Deeper Insight into Genesis and Distribution." Minerals 14, no. 5 (April 28, 2024): 465. http://dx.doi.org/10.3390/min14050465.

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Beryl mineralization in the Nugrus-Sikait domain in the South Eastern Desert (SED) of Egypt occurs as disseminated crystals in granitic pegmatite and quartz, as well as pegmatite veins crosscutting mélange schist and ophiolitic rocks. When granitic pegmatite comes into contact with the ophiolitic rocks, phlogopite and amphibole schists are formed due to K metasomatism. The ophiolitic mélange is intruded by leucogranite and related pegmatite along the NNW to NW Nugrus shear zone. Beryl samples have been collected from Um Sleimat, Madinat Nugrus, Wadi Abu Rusheid, and Wadi Sikait. Major oxides and in situ trace and rare earth elements (REEs) of beryl and associated minerals were analyzed through EPMA and LA-ICP-MS, respectively. The investigated beryl, based on its color and chemical compositions, can be classified into the two following types: pegmatitic beryl (type I) and schist-related beryl (type II). The former is colorless to pale green, and is mainly restricted in pegmatite veins; it is poor in Cr2O3 (up to 0.03 wt%) and MgO (Nil). The latter, deep green in color, is rich in Cr2O3 (up to 0.27 wt%) and MgO (up to 2.71 wt%), and occurs within quartz veins, phlogopite schists, and tremolite schists. The abundant beryl mineralization in phlogopite schists and their related quartz veins suggests that granite and associated pegmatite are the source rocks for the Be-bearing fluids that migrate along the NW-SE trending deep-seated tectonic zone, such as the Nugrus shear zone. Therefore, the formation of beryl in schists is attributed to the interaction of granitic/pegmatitic-derived Be-bearing fluids with serpentinite and gabbro interlayered with mélange schists. Variations in the trace and REE contents of both beryl types (I and II) indicate their two-stage formation from different compositions of Be-rich fluids, where light REEs, Zr, Nb, Ba, and Th decrease from type I beryl to type II. These two phases of beryl could be attributed to the magmatic/hydrothermal fluids associated with the pegmatite emplacement. The early phase of the late-stage magmatic-derived fluids was closely related to magma evolution and pegmatite formation, forming euhedral type I beryl. The late phase of pegmatite-derived fluids was mixed with serpentinite/schist-derived fluids that cause high V and Cr content in type II beryl. The composition of parent magmas of felsic rocks, the high degree of magma fractionation or the late stage melts, fluid compositions (rich in Be, Li, Cs, Rb, K), and alkali metasomatism, as well as the linear NW-SE trending deep-seated shear zone, are all factors possibly influencing beryl mineralization in the SED of Egypt.

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-Saatdjian, Estéban. "Le mélange des fluides visqueux par advection chaotique." Revue de l'Electricité et de l'Electronique -, no. 04 (1998): 70. http://dx.doi.org/10.3845/ree.1998.038.

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Hu, Wen-Jun, Hong Zhong, Wei-Guang Zhu, and Zhong-Jie Bai. "Rift- and subduction-related crustal sequences in the Jinshajiang ophiolitic mélange, SW China: Insights into the eastern Paleo-Tethys." Lithosphere 11, no. 6 (October 22, 2019): 821–33. http://dx.doi.org/10.1130/l1091.1.

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Abstract The Paleozoic Jinshajiang ophiolitic mélange in southwest China marks an important branch ocean (i.e., the Jinshajiang Ocean) of the Paleo-Tethys. Basic-intermediate rocks are widespread features in the mélange; their formation age is well known, but the petrogenesis has not been well studied, which means that the evolutionary history of the Jinshajiang Ocean is not well constrained. To understand the nature of the mélange and the ocean, we present a set of elemental and isotopic data from two typical crustal sequences in two areas of the Jinshajiang ophiolitic mélange, Zhiyong and Baimaxueshan. The basalts in the ca. 343 Ma Zhiyong crustal sequence show mid-ocean-ridge basalt–like geochemical compositions with Nb/La ratios of 0.98–1.15 and εNd(t) values of +6.5 to +7.7, indicating that the basalts formed in the spreading ridge of the ocean. In contrast, the 283 Ma Baimaxueshan crustal sequence consists of gabbros and basaltic-andesitic lavas, which have an arc affinity with Nb/La ratios of 0.54–0.67 and εNd(t) values of +5.1 to +6.5. The geochemical differences were not caused by crustal assimilation but reflect mantle metasomatism by fluids dehydrated from the subducting slab. Therefore, we propose that the Zhiyong and Baimaxueshan crustal sequences formed in seafloor spreading and subduction settings, which were related to the opening and closure of the ocean, respectively.

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Hashimoto, Y., M. Enjoji, A. Sakaguchi, and G. Kimura. "In situpressure-temperature conditions of a tectonic mélange: Constraints from fluid inclusion analysis of syn-mélange veins." Island Arc 12, no. 4 (December 2003): 357–65. http://dx.doi.org/10.1046/j.1440-1738.2003.00405.x.

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Fisher, Donald M., John N. Hooker, Andrew J. Smye, and Tsai-Wei Chen. "Insights from the geological record of deformation along the subduction interface at depths of seismogenesis." Geosphere 17, no. 6 (November 4, 2021): 1686–703. http://dx.doi.org/10.1130/ges02389.1.

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Abstract Subduction interfaces are loci of interdependent seismic slip behavior, fluid flow, and mineral redistribution. Mineral redistribution leads to coupling between fluid flow and slip behavior through decreases in porosity/permeability and increases in cohesion during the interseismic period. We investigate this system from the perspective of ancient accretionary complexes with regional zones of mélange that record noncoaxial strain during underthrusting adjacent to the subduction interface. Deformation of weak mudstones is accompanied by low-grade metamorphic reactions, dissolution along scaly microfaults, and the removal of fluid-mobile chemical components, whereas stronger sandstone blocks preserve veins that contain chemical components depleted in mudstones. These observations support local diffusive mass transport from scaly fabrics to veins during interseismic viscous coupling. Underthrusting sediments record a crack porosity that fluctuates due to the interplay of cracking and precipitation. Permanent interseismic deformation involves pressure solution slip, strain hardening, and the development of new shears in undeformed material. In contrast, coseismic slip may be accommodated within observed narrow zones of cataclastic deformation at the top of many mélange terranes. A kinetic model implies interseismic changes in physical properties in less than hundreds of years, and a numerical model that couples an earthquake simulator with a fluid flow system depicts a subduction zone interface governed by feedbacks between fluid production, permeability, hydrofracturing, and aging via mineral precipitation. During an earthquake, interseismic permeability reduction is followed by coseismic rupture of low permeability seals and fluid pressure drop in the seismogenic zone. Updip of the seismogenic zone, there is a post-seismic wave of higher fluid pressure that propagates trenchward.

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SPÖTL, C., F. J. LONGSTAFFE, K. RAMSEYER, M. J. KUNK, and R. WIESHEU. "Fluid-rock reactions in an evaporitic mélange, Permian Haselgebirge, Austrian Alps." Sedimentology 45, no. 6 (December 1998): 1019–44. http://dx.doi.org/10.1046/j.1365-3091.1998.00188.x.

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HASHIMOTO, YOSHITAKA, MIO EIDA, TAKAYUKI KIRIKAWA, RYOKO IIDA, MIE TAKAGI, NORIKO FURUYA, AKIRA NIKAIZO, TAKETO KIKUCHI, and TOSHIO YOSHIMITSU. "Large amount of fluid migration around shallow seismogenic depth preserved in tectonic mélange: Yokonami mélange, the Cretaceous Shimanto Belt, Kochi, Southwest Japan." Island Arc 21, no. 1 (February 28, 2012): 53–64. http://dx.doi.org/10.1111/j.1440-1738.2011.00806.x.

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Ascione, Alessandra, Sergio Nardò, and Stefano Mazzoli. "The MS 6.9, 1980 Irpinia Earthquake from the Basement to the Surface: A Review of Tectonic Geomorphology and Geophysical Constraints, and New Data on Postseismic Deformation." Geosciences 10, no. 12 (December 9, 2020): 493. http://dx.doi.org/10.3390/geosciences10120493.

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The MS 6.9, 1980 Irpinia earthquake occurred in the southern Apennines, a fold and thrust belt that has been undergoing post-orogenic extension since ca. 400 kyr. The strongly anisotropic structure of fold and thrust belts like the Apennines, including late-orogenic low-angle normal faults and inherited Mesozoic extensional features besides gently dipping thrusts, result in a complex, overall layered architecture of the orogenic edifice. Effective decoupling between deep and shallow structural levels of this mountain belt is related to the strong rheological contrast produced by a fluid-saturated, shale-dominated mélange zone interposed between buried autochthonous carbonates—continuous with those exposed in the foreland to the east—and the allochthonous units. The presence of fluid reservoirs below the mélange zone is shown by a high VP/VS ratio—which is a proxy for densely fractured fluid-saturated crustal volumes—recorded by seismic tomography within the buried autochthonous carbonates and the top part of the underlying basement. These crustal volumes, in which background seismicity is remarkably concentrated, are fed by fluids migrating along the major active faults. High pore fluid pressures, decreasing the yield stress, are recorded by low stress-drop values associated with the earthquakes. On the other hand, the mountain belt is characterized by substantial gas flow to the surface, recorded as both distributed soil gas emissions and vigorous gas vents. The accumulation of CO2-brine within a reservoir located at hypocentral depths beneath the Irpinia region is not only interpreted to control a multiyear cyclic behavior of microseismicity, but could also play a role in ground motions detected by space-based geodetic measurements in the postseismic period. The analysis carried out in this study of persistent scatterer interferometry synthetic aperture radar (PS-InSAR) data, covering a timespan ranging from 12 to 30 years after the 1980 mainshock, points out that ground deformation has affected the Irpinia earthquake epicentral area in the last decades. These ground motions could be a result of postseismic afterslip, which is well known to occur over years or even decades after a large mainshock such as the 23 November 1980, MS 6.9 earthquake due to cycles of CO2-brine accumulation at depth and its subsequent release by Mw ≥ 3.5 earthquakes, or most likely by a combination of both. Postseismic afterslip controls geomorphology, topography, and surface deformation in seismically active areas such as that of the present study, characterized by ~M 7 earthquakes. Yet, this process has been largely overlooked in the case of the 1980 Irpinia earthquake, and one of the main aims of this study is to fill such the substantial gap of knowledge for the epicentral area of some of the most destructive earthquakes that have ever occurred in Italy.

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Khanchuk, A. I., V. V. Ratkin, and O. A. Eliseeva. "SKARN-BOROSILICATE GIANT DEPOSITS: DERIVATES OF THE FLUID-HYDROTHERMAL REWORKING OF ATOLL FRAGMENTS IN A SUBDUCTION MELANGE OF MESOZOIC OROGENIC BELTS OF ASIA." Tikhookeanskaya Geologiya 41, no. 1 (2022): 3–12. http://dx.doi.org/10.30911/0207-4028-2022-41-1-3-12.

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Geological observations coupled with geochemical, isotopic and thermobaric-geochemical research of danburite ores of skarn-borosilicate deposits unique in their reserves in the Sikhote-Alin (Dalnegorskoe) and in the Pamir (Ak-Arkhar) indicated lagoonal strata and evaporites in the form of atoll fragments within the Mesozoic subduction mélange as the most probable boron source, which preceded the skarn formation. At the Dalnegorskoe deposit, the fact that boron is mobilized by skarn-forming solutions from evaporite accumulations is directly confirmed by isotopically heavier composition of boron (δ11В = +17.7 ‰) corresponding to marine evaporites, and a typical enrichment of fluid in lithium.

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Mermond, Y., M. Feidt, and C. Marvillet. "Propriétés thermodynamiques et physiques des mélanges de fluides frigorigènes et d'huiles." International Journal of Refrigeration 22, no. 7 (November 1999): 569–79. http://dx.doi.org/10.1016/s0140-7007(99)00015-8.

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Cerchiari, Anna, Francesca Remitti, Silvia Mittempergher, Andrea Festa, Federico Lugli, and Anna Cipriani. "Cyclical variations of fluid sources and stress state in a shallow megathrust-zone mélange." Journal of the Geological Society 177, no. 3 (February 5, 2020): 647–59. http://dx.doi.org/10.1144/jgs2019-072.

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23

Sarifakioglu, E., Y. Dilek, and M. Sevin. "Jurassic–Paleogene intra-oceanic magmatic evolution of the Ankara Mélange, North-Central Anatolia, Turkey." Solid Earth Discussions 5, no. 2 (November 13, 2013): 1941–2004. http://dx.doi.org/10.5194/sed-5-1941-2013.

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Abstract. Oceanic rocks in the Ankara Mélange along the Izmir–Ankara–Erzincan suture zone (IAESZ) in North-Central Anatolia include locally coherent ophiolite complexes (~179 Ma and ~80 Ma), seamount or oceanic plateau volcanic units with pelagic and reefal limestones (96.6 ± 1.8 Ma), metamorphic rocks with ages of 187.4 ± 3.7 Ma, 158.4 ± 4.2 Ma, and 83.5 ± 1.2 Ma, and subalkaline to alkaline volcanic and plutonic rocks of an island arc origin (~67–63 Ma). All but the arc rocks occur in a shaly-graywacke and/or serpentinite matrix, and are deformed by south-vergent thrust faults and folds that developed in the Middle to Late Eocene due to continental collisions in the region. Ophiolitic volcanic rocks have mid-ocean ridge (MORB) and island arc tholeiite (IAT) affinities showing moderate to significant LILE enrichment and depletion in Nb, Hf, Ti, Y and Yb, which indicate the influence of subduction-derived fluids in their melt evolution. Seamount/oceanic plateau basalts show ocean island basalt (OIB) affinities. The arc-related volcanic rocks, lamprophyric dikes and syeno-dioritic plutons exhibit high-K shoshonitic to medium-to high-K calc-alkaline compositions with strong enrichment in LILE, REE and Pb, and initial &varepsilon;Nd values between +1.3 and +1.7. Subalkaline arc volcanic units occur in the northern part of the mélange, whereas the younger alkaline volcanic rocks and intrusions (lamprophyre dikes and syeno-dioritic plutons) in the southern part. The Early to Late Jurassic and Late Cretaceous epidote-actinolite, epidote-chlorite and epidote-glaucophane schists represent the metamorphic units formed in a subduction channel in the Northern Neotethys. The Middle to Upper Triassic neritic limestones spatially associated with the seamount volcanic rocks indicate that the Northern Neotethys was an open ocean with its MORB-type oceanic lithosphere by the Early Triassic. The Latest Cretaceous–Early Paleocene island arc volcanic, dike and plutonic rocks with subalkaline to alkaline geochemical affinities represent intraoceanic magmatism that developed on and across the subduction-accretion complex above a N-dipping, southward-rolling subducted lithospheric slab within the Northern Neotethys. The Ankara Mélange thus exhibits the record of ~120–130 million years of oceanic magmatism in geological history of the Northern Neotethys.

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Lázaro, C., I. F. Blanco-Quintero, C. Marchesi, D. Bosch, Y. Rojas-Agramonte, and A. García-Casco. "The imprint of subduction fluids on subducted MORB-derived melts (Sierra del Convento Mélange, Cuba)." Lithos 126, no. 3-4 (October 2011): 341–54. http://dx.doi.org/10.1016/j.lithos.2011.07.011.

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Penniston-Dorland, Sarah C., Sorena S. Sorensen, Richard D. Ash, and Supriya V. Khadke. "Lithium isotopes as a tracer of fluids in a subduction zone mélange: Franciscan Complex, CA." Earth and Planetary Science Letters 292, no. 1-2 (March 15, 2010): 181–90. http://dx.doi.org/10.1016/j.epsl.2010.01.034.

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26

Boumaraf, Latra, and André Lallemand. "Performances d'une machine tritherme à éjecteur utilisant des mélanges de fluides frigorigènes." International Journal of Refrigeration 22, no. 7 (November 1999): 580–89. http://dx.doi.org/10.1016/s0140-7007(99)00016-x.

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27

Kawamoto, Tatsuhiko, Andreas Hertwig, Hans-Peter Schertl, and Walter V. Maresch. "Fluid inclusions in jadeitite and jadeite-rich rock from serpentinite mélanges in northern Hispaniola: Trapped ambient fluids in a cold subduction channel." Lithos 308-309 (May 2018): 227–41. http://dx.doi.org/10.1016/j.lithos.2018.02.024.

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28

Yamaguchi, Asuka, Tadahiro Shibata, Kohtaro Ujiie, and Gaku Kimura. "Deformation and fluid flow in seismogenic subduction zone: The Mugi Mélange in the Shimanto Belt." Journal of the Geological Society of Japan 115, Supplement (2009): S21—S36. http://dx.doi.org/10.5575/geosoc.115.s21.

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29

Tumiati, Simone, Gaston Godard, Silvana Martin, Urs Klötzli, and Damiano Monticelli. "Fluid-controlled crustal metasomatism within a high-pressure subducted mélange (Mt. Hochwart, Eastern Italian Alps)." Lithos 94, no. 1-4 (March 2007): 148–67. http://dx.doi.org/10.1016/j.lithos.2006.06.009.

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30

Sarifakioglu, E., Y. Dilek, and M. Sevin. "Jurassic–Paleogene intraoceanic magmatic evolution of the Ankara Mélange, north-central Anatolia, Turkey." Solid Earth 5, no. 1 (February 19, 2014): 77–108. http://dx.doi.org/10.5194/se-5-77-2014.

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Abstract. Oceanic rocks in the Ankara Mélange along the Izmir–Ankara–Erzincan suture zone (IAESZ) in north-central Anatolia include locally coherent ophiolite complexes (~ 179 Ma and ~ 80 Ma), seamount or oceanic plateau volcanic units with pelagic and reefal limestones (96.6 ± 1.8 Ma), metamorphic rocks with ages of 256.9 ± 8.0 Ma, 187.4 ± 3.7 Ma, 158.4 ± 4.2 Ma, and 83.5 ± 1.2 Ma indicating northern Tethys during the late Paleozoic through Cretaceous, and subalkaline to alkaline volcanic and plutonic rocks of an island arc origin (~ 67–63 Ma). All but the arc rocks occur in a shale–graywacke and/or serpentinite matrix, and are deformed by south-vergent thrust faults and folds that developed in the middle to late Eocene due to continental collisions in the region. Ophiolitic volcanic rocks have mid-ocean ridge (MORB) and island arc tholeiite (IAT) affinities showing moderate to significant large ion lithophile elements (LILE) enrichment and depletion in Nb, Hf, Ti, Y and Yb, which indicate the influence of subduction-derived fluids in their melt evolution. Seamount/oceanic plateau basalts show ocean island basalt (OIB) affinities. The arc-related volcanic rocks, lamprophyric dikes and syenodioritic plutons exhibit high-K shoshonitic to medium- to high-K calc-alkaline compositions with strong enrichment in LILE, rare earth elements (REE) and Pb, and initial εNd values between +1.3 and +1.7. Subalkaline arc volcanic units occur in the northern part of the mélange, whereas the younger alkaline volcanic rocks and intrusions (lamprophyre dikes and syenodioritic plutons) in the southern part. The late Permian, Early to Late Jurassic, and Late Cretaceous amphibole-epidote schist, epidote-actinolite, epidote-chlorite and epidote-glaucophane schists represent the metamorphic units formed in a subduction channel in the northern Neotethys. The Middle to Upper Triassic neritic limestones spatially associated with the seamount volcanic rocks indicate that the northern Neotethys was an open ocean with its MORB-type oceanic lithosphere by the early Triassic (or earlier). The latest Cretaceous–early Paleocene island arc volcanic, dike and plutonic rocks with subalkaline to alkaline geochemical affinities represent intraoceanic magmatism that developed on and across the subduction–accretion complex above a N-dipping, southward-rolling subducted lithospheric slab within the northern Neotethys. The Ankara Mélange thus exhibits the record of ~ 120–130 million years of oceanic magmatism in geological history of the northern Neotethys.

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Mulapi, W., A. Pilatte, and R. Jadot. "Algorithmes simples pour l'évaluation rapide des propriétés des mélanges binaires de fluides frigorigènes." International Journal of Refrigeration 13, no. 6 (November 1990): 364–70. http://dx.doi.org/10.1016/0140-7007(90)90025-r.

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32

Breeding, Christopher M., Jay J. Ague, and Michael Bröcker. "Fluid–metasedimentary rock interactions in subduction-zone mélange: Implications for the chemical composition of arc magmas." Geology 32, no. 12 (2004): 1041. http://dx.doi.org/10.1130/g20877.1.

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33

Furman, Tanya, Barry B. Hanan, Megan Pickard Sjoblom, Biltan Kürkcüoğlu, Kaan Sayit, Erdal Şen, Pinar Alıcı Şen, and Tekin Yürür. "Evolution of mafic lavas in Central Anatolia: Mantle source domains." Geosphere 17, no. 6 (November 4, 2021): 1631–46. http://dx.doi.org/10.1130/ges02329.1.

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Abstract We present new Sr-Nd-Pb-Hf isotopic data on mafic lavas from the Sivas, Develidağ, Erciyes, and Erkilet volcanic complexes in central Turkey and Tendürek in eastern Turkey to evaluate the mantle sources for volcanism in the context of the geodynamic evolution of the Anatolian microplate. Early Miocene through Quaternary volcanism in Western Anatolia and latest Miocene through Quaternary activity in Central Anatolia were dominated by contributions from two distinct source regions: heterogeneous metasomatized or subduction-modified lithosphere, and roughly homogeneous sublithospheric ambient upper mantle; we model the source contributions through mixing between three end members. The sublithospheric mantle source plots close to the Northern Hemisphere reference line (NHRL) with radiogenic 206Pb/204Pb of ∼19.15, while the other contributions plot substantially above the NHRL in Pb isotope space. The lithospheric source is heterogeneous, resulting from variable pollution by subduction-related processes likely including direct incorporation of sediment and/or mélange; its range in radiogenic isotopes is defined by regional oceanic sediment and ultrapotassic melts of the subcontinental lithospheric mantle. The geochemical impact of this contribution is disproportionately large, given that subduction-modified lithosphere and/or ocean sediment dominates the Pb isotope signatures of mafic Anatolian lavas. Subduction of the Aegean or Tethyan seafloor, associated with marked crustal shortening, took place throughout the region until ca. 16–17 Ma, after which time broad delamination of the thickened lower crust and/or the Tethyan slab beneath Central Anatolia allowed for sediment and/or mélange and slab-derived fluids to be released into the overlying evolving modified mantle. Aggregation of melts derived from both mantle and lithospheric domains was made possible by upwelling of warm asthenospheric material moving around and through the complexly torn younger Aegean-Cyprean slab that dips steeply to the north beneath southern Anatolia.

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Prevec, Stephen A. "Igneous Rock Associations 23. The Bushveld Complex, South Africa: New Insights and Paradigms." Geoscience Canada 45, no. 3-4 (January 28, 2019): 117–35. http://dx.doi.org/10.12789/geocanj.2018.45.138.

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SUMMARYThe Bushveld Complex has continued to serve as the basis for study into the fundamental nature of petrological processes for layered intrusion formation and for oxide and sulphide hosted Platinum Group Element (PGE)–Cu–Ni ore deposits. These studies have included discoveries in terms of the physical extent of Bushveld magmatism, both laterally and internally. Lateral variations in the mafic to ultramafic Rustenburg Layered Suite of the Northern Lobe of the complex have also revealed petrologically distinctive Upper Critical Zone equivalent rocks (the so-called Flatreef) with enhanced contamination and mineralization traits that reflect a transition between Eastern and Western Lobe equivalent stratigraphy and Platreef-style complexity. Traditional magma mixing models have been re-examined in light of radiogenic isotopic evidence for crustal involvement early in the chromite precipitation or formation process, combined with evidence for associated heterogeneous fluid contents, cryptic layering profiles, and textural evidence. A wide variety of alternative ore-genesis models have been proposed as a consequence. The fundamental mechanics of magma chamber processes and the existence of the magma chamber as an entity have been called into question through various lines of evidence which have promoted the concept of progressive emplacement of the complex as a stack of not-necessarily-quite-sequentially intruded sills (with or without significant quantities of transported phenocrysts), emplaced into variably crystallized and compacted crystal-liquid mush mixtures, modified by compaction-driven late magmatic fluid (silicate and aqueous) activity. Alternatively, petrological and geochemical observations have been used to discount these interpretations in favour of more conventional cooling and gravity-driven accumulation of silicate and ore minerals in a large, liquid-dominated system.RÉSUMÉLe complexe de Bushveld a demeuré à la base d’études sur la nature fondamentale des processus pétrologiques de formation d’intrusions litées et des gîtes des éléments du groupe platine (ÉGP)-Cu-Ni hébergés dans les oxydes et les sulfures. Ces études ont comporté des découvertes sur l’étendue physique, à la fois latérale et interne, du magmatisme de Bushveld. Les variations latérales de la suite stratifiée et mafique à ultramafique Rustenburg du lobe nord du complexe ont également révélé des roches équivalentes pétrologiquement distinctes de la zone critique supérieure (le communément désigné Flatreef) avec des traits de contamination et de minéralisation accrus qui reflètent une transition entre la stratigraphie équivalente des lobes est et ouest et la complexité de type Platreef. Les modèles traditionnels de mélanges magmatiques ont été réexaminés à la lumière de preuves isotopiques radiogéniques indiquant une implication de la croûte au début du processus de précipitation ou de formation de la chromite, combinées à des preuves de contenu fluide hétérogène associé, de profils de litage cryptique et de preuves texturales. Ainsi, une grande variété de modèles alternatifs de genèse de minerai a été proposée. La mécanique fondamentale des processus de la chambre magmatique et l'existence de la chambre magmatique en tant qu'entité ont été remises en question au moyen de divers éléments de preuve qui ont mis en avant le concept de mise en place progressive du complexe sous forme d'un empilement non-nécessairement séquentiel de sills injectés (avec ou sans quantités significatives de phénocristaux transportés) mis en place dans des mélanges de bouillie cristaux/liquide à cristallisation et compaction variable, modifiés par une activité tardive de fluide magmatique (silicaté et aqueux) induite par la compaction. Alternativement, des observations pétrologiques et géochimiques ont été utilisées pour écarter ces interprétations en faveur d'un processus plus conventionnel de refroidissement et d’accumulation de minérais silicatés et minéralisés induite par la gravité dans un vaste système à dominance liquide.

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JARMOŁOWICZ-SZULC, Katarzyna, and Krystyna WOŁKOWICZ. "New achievements in the mineral studies by use of the Raman microspectroscopy." Biuletyn Państwowego Instytutu Geologicznego 474, no. 474 (March 28, 2019): 23–30. http://dx.doi.org/10.5604/01.3001.0013.0836.

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By the means of the technique of the Raman microspectrometry, the complex history of the Earth can be better understood. That is why the Raman spectra determinations are the object of interest in the present paper. The examples of such experiments are presented based on the analyses performed in last years in different scientific centers (Potsdam, Banská Bystrica, Budapest). The identification of inclusion content is shown and the conclusions are drawn for fluid inclusions in some quartz samples from two different localities in Poland – in the Carpathians and in the Fore-Sudetic Block. The implications of the Raman analyses are discussed. It results from the Raman analyses performed that not fluorescing, gas-filled bubbles of huge fluid inclusions from the Jabłonki and Rabe vicinity (the tectonic mélange zone in the Carpathians) have the complex composition of CH4, CO2 and N2 in different mutual proportions dependent on the sample and locality. In another place, despite the fluorescing background, only methane has been identified by Raman spectra. Similar gas composition was determined in the inclusions in the vein quartz in the Wądroże Wielkie area (the Fore-Sudetic Block).

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Guillemet, P., and O. Lottin. "Modélisation des équilibres liquide–vapeur, application aux mélanges d'huile et de fluides frigorigènes HFC." International Journal of Refrigeration 27, no. 2 (March 2004): 102–10. http://dx.doi.org/10.1016/j.ijrefrig.2003.09.004.

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37

Miyazoe, T., M. Enami, T. Nishiyama, and Y. Mori. "Retrograde strontium metasomatism in serpentinite mélange of the Kurosegawa Zone in central Kyushu, Japan." Mineralogical Magazine 76, no. 3 (June 2012): 635–47. http://dx.doi.org/10.1180/minmag.2012.076.3.14.

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AbstractStrontium-rich epidote, including epidote-(Sr) and epidote with major amounts of Sr (i.e. epidote containing up to 17.3 wt.% SrO), was found in pumpellyite schist and epidote blueschist in a tectonic block in the serpentinite mélange of the Kurosegawa Zone, central Kyushu, Japan. The tectonic block is 20 m wide and made primarily of lawsonite blueschist, with subordinate amounts of pumpellyite schist and epidote blueschist. The pumpellyite schist typically occurs at the edge of the block and is composed mainly of pumpellyite with subordinate amounts of strontium-poor epidote, albite and chlorite, and thin veins of fine-grained calcite and clinopyroxene. Epidote-(Sr) forms rims around strontium-poor epidote, fills fractures in strontium-poor epidote and also occurs interstitially between pumpellyite aggregates and along the boundaries between pumpellyite and calcite-clinopyroxene veins. The epidote blueschist is found between the pumpellyite schist and lawsonite blueschist, and consists mainly of sodic amphibole, epidote and titanite, with albite veining. Strontium-rich epidote occurs as rims, replacing Sr-poor epidote near the albite vein. The bulk strontium contents of the rocks are as follows: lawsonite blueschist (200 ppm), epidote blueschist (2800 ppm) and pumpellyite schist (~10,700 ppm). The chemical and petrological characteristics of the Sr-rich epidote-bearing metabasites suggest that the infiltration of a metamorphic fluid promoted extensive Sr metasomatism during the later stages of high-pressure metamorphism.

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SCARSI, MARCO, CRISTINA MALATESTA, and SILVIA FORNASARO. "Lawsonite-bearing eclogite from a tectonic mélange in the Ligurian Alps: new constraints for the subduction plate-interface evolution." Geological Magazine 155, no. 2 (May 23, 2017): 280–97. http://dx.doi.org/10.1017/s0016756817000395.

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AbstractLawsonite eclogites are rare rocks and have been described from only a few localities in the world. Lawsonite-bearing assemblages are highly unstable and physico-chemical processes linked to exhumation may destroy them; only aggregates interpreted as pseudomorphs after lawsonite could be often recognized. In this paper, we present a detailed structural and petrological study of an area in the northwestern sector of the metaophiolitic high-pressure Voltri Massif (Ligurian Western Alps, Italy). The study area is characterized by a lawsonite-bearing eclogitic metagabbro associated with carbonated serpentinites and glaucophanic metasediments. The metagabbro body reached eclogitic metamorphic peak conditions at T = 465–477°C and P = 20.9–24.4 kbar, with H2O continuously supplied to the system. H2O under-saturated conditions, with the occurrence of both lawsonite and epidote, characterized the exhumation path. Both the low temperature recorded by the body and the occurrence of variously carbonated serpentinites led us to interpret this area as a portion of the top of the subducted slab, coupled with a ‘cool’ mantle wedge, where both aqueous fluids and carbonate-rich fluids were present. The occurrence of rocks belonging to different paleogeographic domains (e.g. continent versus ocean) and the multiple deformations recorded by the metagabbro suggest that this area was nearby the slab–mantle interface. This sector was thus affected by a shear regime that acted in a low-viscosity serpentinite channel, bringing these high-pressure rocks back to the surface.

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Morishita, T. "Occurrence and chemical composition of barian feldspars in a jadeitite from the Itoigawa-Ohmi district in the Renge high-P/T-type metamorphic belt, Japan." Mineralogical Magazine 69, no. 1 (February 2005): 39–51. http://dx.doi.org/10.1180/0026461056910237.

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AbstractCoexisting Ba-rich (Cn56–59Or40–42Ab2An0–1) and Ba-poor (Cn7–15Or83–92Ab1–3An0–1) feldspars were found in a jadeitite collected from the Itoigawa-Ohmi district in the Renge high-P/T-type metamorphic belt, Japan. There is an apparent compositional gap in these barian feldspars at Cn15–56 in the ternary system BaAl2Si2O8–KAlSi3O8–NaAlSi3O8. Barian feldspars occur as interstitial phases between subhedral to euhedral jadeite and prehnite, and sometimes cut a jadeite crystal. The occurrence of barian feldspars combined with the texture and mineral assemblages of the host jadeitite suggest that barian feldspars were formed from residual fluids after the formation of jadeite and prehnite from primary aqueous fluids at low-T conditions (<350°C) and pressure of ~0.6 GPa. The Ba content in the residual fluids would increase locally during the formation of jadeite because Ba is incompatible with clinopyroxene. This study supports the suggestion that Ba-rich minerals are not uncommon in jadeitites and albitites/metasomatized rocks that occur as tectonic blocks in serpentinite-matrix mélanges. Barium is an important minor element in metasomatizing fluids related to the formation of jadeitites and might have been derived from subducted oceanic crust at the beginning of the subduction.

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GRAGNIC, G., V. CHEVALIER, and F. ESPERET. "La production d’énergie renouvelable à la station d’épuration d’Angers Loire Métropole." Techniques Sciences Méthodes, no. 1-2 (February 20, 2020): 53–61. http://dx.doi.org/10.36904/tsm/201901053.

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Si les stations d’épuration remplissent parfaitement leur fonction première, à savoir traiter les eaux usées de manière performante, cela se fait en consommant une quantité d’énergie significative. La consommation d’électricité des secteurs de l’eau et de l’assainissement représente 3,5 % de la consommation totale d’électricité dans l’Union européenne. L’enjeu pour les installations de traitement est aujourd’hui d’atteindre l’autosuffisance en énergie, de réduire les émissions carbones et d’explorer toutes les possibilités permettant de maîtriser les consommations d’énergie. La digestion anaérobie et l’injection du biogaz dans le réseau de gaz naturel offrent de nouvelles opportunités qui progressent rapidement. Près de 144 GWh /an (retours d’expérience Gaz réseau distribution France GRDF) sont déjà injectés pour un potentiel estimé à plus de 1 500 GWh/an. La production d’énergie renouvelable issue du biogaz est un des leviers majeurs qui permettra à la filière de l’eau d’atteindre la neutralité carbone et l’autosuffisance énergétique. Le présent article présente la production d’énergie réalisée par la station d’épuration d’Angers Loire Métropole, qui injecte, depuis juin 2017, dans le réseau public de distribution de gaz naturel opéré par GRDF, le biométhane obtenu après purification du biogaz issu de la digestion des boues. La quantité d’énergie injectée dans le réseau, 15 000 MWh/an et bientôt 18 000 MWh/an après substitution du biogaz consommé pour le process par la chaleur fatale présente sur le site, peut être comparée à la consommation d’électricité annuelle : 8 660 MWh puis 9 030 MWh après augmentation de la quantité injectée. Compte tenu du coefficient de conversion de l’électricité en énergie primaire utilisé en France dans le cadre de la réglementation thermique de 2012 (RT2012), égal à 2,58, l’autonomie de la station atteindra prochainement 78 %. Les gains supplémentaires pourront résulter de l’amélioration du rendement de digestion, objet de programme de recherche, et éventuellement de la mutualisation de l’outil si la réglementation relative au mélange des boues évoluait de façon à autoriser ce mélange en méthanisation.

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FALIPOU, E., S. GILLOT, J. P. CANLER, and J. M. PERRET. "Digestion anaérobie des boues en station d’épuration : état de l’art du parc français." Techniques Sciences Méthodes, no. 9 (September 21, 2020): 57–69. http://dx.doi.org/10.36904/tsm/202009057.

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La digestion des boues de station d’épuration suscite de plus en plus d’intérêt auprès des collectivités. Ce procédé biologique permet en effet de réduire de façon importante le volume des boues produites, de les stabiliser et de générer du biogaz. Ce biogaz peut être valorisé sous forme d’énergie thermique et/ou électrique, être utilisé comme biocarburant, ou être injecté dans le réseau de gaz de ville depuis juin 2014, avec la modification de l’arrêté du 23 novembre 2011. Motivée par cette évolution réglementaire, cette étude a permis de réaliser un état des lieux des pratiques actuelles en France concernant la digestion des boues d’épuration. Les résultats présentés ont été obtenus à la suite d’une enquête réalisée auprès des exploitants de stations d’épuration équipées d’une filière de digestion. 96 installations de ce type ont pu être répertoriées en France métropolitaine. Les réponses au questionnaire technique envoyé ont permis d’identifier les pratiques majoritaires ainsi que les problèmes rencontrés en exploitation. Les digesteurs sont alimentés principalement avec un mélange de boues primaires et de boues secondaires, et sont conçus pour fonctionner en chauffant les boues à 37 °C ou 55 °C grâce au biogaz produit. Bien que les exploitants ajoutent parfois des graisses au mélange, la codigestion reste peu utilisée du fait des contraintes réglementaires. Les performances obtenues en matière de réduction du volume des boues et de production de biogaz ont pu être déterminées et reliées à la nature des boues introduites. Malgré quelques difficultés liées au bouchage de canalisations par des filasses, à la gestion des retours en tête chargés en azote ou au respect des normes de qualité du biogaz et des boues déshydratées, les exploitants se disent globalement satisfaits et un nombre croissant de projets de digestion a pu être mis en évidence. Le biogaz produit est désormais majoritairement valorisé afin de produire de l’énergie en plus de chauffer le digesteur et, à fin 2018, huit stations ont déjà opté pour l’injection de biométhane épuré dans les réseaux de distribution de gaz.

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Ague, Jay J. "Models of permeability contrasts in subduction zone mélange: Implications for gradients in fluid fluxes, Syros and Tinos Islands, Greece." Chemical Geology 239, no. 3-4 (April 2007): 217–27. http://dx.doi.org/10.1016/j.chemgeo.2006.08.012.

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Waldron, J. W. F., D. Turner, and K. M. Stevens. "Stratal disruption and development of mélange, Western Newfoundland: effect of high fluid pressure in an accretionary terrain during ophiolite emplacement." Journal of Structural Geology 10, no. 8 (January 1988): 861–73. http://dx.doi.org/10.1016/0191-8141(88)90100-9.

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KING, R., G. BEBOUT, T. MORIGUTI, and E. NAKAMURA. "Elemental mixing systematics and Sr–Nd isotope geochemistry of mélange formation: Obstacles to identification of fluid sources to arc volcanics." Earth and Planetary Science Letters 246, no. 3-4 (June 30, 2006): 288–304. http://dx.doi.org/10.1016/j.epsl.2006.03.053.

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Hashimoto, Y., A. Nikaizo, and G. Kimura. "A geochemical estimation of fluid flux and permeability for a fault zone in Mugi mélange, the Cretaceous Shimanto Belt, SW Japan." Journal of Structural Geology 31, no. 2 (February 2009): 208–14. http://dx.doi.org/10.1016/j.jsg.2008.12.001.

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Blanco-Quintero, Idael Francisco, C. Lázaro, A. García-Casco, J. A. Proenza, and Y. Rojas-Agramonte. "Barium-rich fluids and melts in a subduction environment (La Corea and Sierra del Convento mélanges, eastern Cuba)." Contributions to Mineralogy and Petrology 162, no. 2 (December 25, 2010): 395–413. http://dx.doi.org/10.1007/s00410-010-0603-2.

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Kapsiotis, Argyrios N. "Alteration of mélange-hosted chromitites from Korydallos, Pindos ophiolite complex, Greece: evidence for modification by a residual high-T post-magmatic fluid." Acta Geologica Polonica 64, no. 4 (December 1, 2014): 473–94. http://dx.doi.org/10.2478/agp-2014-0025.

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Abstract The peridotites from the area of Korydallos, in the Pindos ophiolitic massif, crop out as deformed slices of a rather dismembered sub-oceanic, lithospheric mantle section and are tectonically enclosed within the Avdella melange. The most sizeable block is a chromitite-bearing serpentinite showing a mesh texture. Accessory, subhedral to euhedral Cr-spinels in the serpentinite display Cr# [Cr/(Cr + Al)] values that range from 0.36 to 0.42 and Mg# [Mg/(Mg+ Fe2+ )] values that vary between 0.57 and 0.62, whereas the TiO2 content may be up to 0.47 wt.%. The serpentinite fragment is characterized by low abundances of magmaphile elements (Al2 O3 : 0.66 wt.%, CaO: 0.12 wt.%, Na2 O: 0.08 wt.%, TiO2 : 0.007 wt.%, Sc: 4 ppm) and enrichment in compatible elements (Cr: 2780 ppm and Ni: 2110 ppm). Overall data are in accordance with derivation of the serpentinite exotic block from a dunite that was formed in the mantle region underneath a back-arc basin before tectonic incorporation in the Korydallos melange. Two compositionally different chromitite pods are recognized in the studied serpentinite fragment, a Cr-rich chromitite and a high-Al chromitite, which have been ascribed to crystallization from a single, progressively differentiating MORB/IAT melt. Although both pods are fully serpentinized only the Al-rich one shows signs of limited Cr-spinel replacement by an opaque spinel phase and clinochlore across grain boundaries and fractures. Modification of the ore-making Cr-spinel is uneven among the Al-rich chromitite specimens. Textural features such as olivine replacement by clinochlore and clinochlore disruption by serpentine indicate that Cr-spinel alteration is not apparently related to serpentinization. From the unaltered Cr-spinel cores to their reworked boundaries the Al2 O3 and MgO abundances decrease, being mainly compensated by FeOt and Cr2 O3 increases. Such compositional variations are suggestive of restricted ferrian chromite (and minor magnetite) substitution for Cr-spinel during a short-lived but relatively intense, low amphibolite facies metamorphic episode (temperature: 400-700 °C). The presence of tremolite and clinochlore in the interstitial groundmass of the high-Al chromitite and their absence from the Cr-rich chromitite matrix imply that after chromitite formation a small volume of a high temperature, post-magmatic fluid reacted with Cr-spinel, triggering its alteration.

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Smeraglia, Luca, Luca Aldega, Stefano M. Bernasconi, Andrea Billi, Chiara Boschi, Antonio Caracausi, Eugenio Carminati, et al. "The role of trapped fluids during the development and deformation of a carbonate/shale intra-wedge tectonic mélange (Mt. Massico, Southern Apennines, Italy)." Journal of Structural Geology 138 (September 2020): 104086. http://dx.doi.org/10.1016/j.jsg.2020.104086.

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Gorman, J. K., S. C. Penniston-Dorland, H. R. Marschall, and R. J. Walker. "The roles of mechanical mixing and fluid transport in the formation of reaction zones in subduction-related mélange: Evidence from highly siderophile elements." Chemical Geology 525 (October 2019): 96–111. http://dx.doi.org/10.1016/j.chemgeo.2019.07.004.

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Boussetta, A. "Étude thermomécanique de la condensation des fluides frigorigènes purs et mélanges azéotropes et quasi-azéotropes à l'intérieur d'une conduite horizontale." Mécanique & Industries 4, no. 3 (June 2003): 159–67. http://dx.doi.org/10.1016/s1296-2139(03)00036-8.

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Journal articles on the topic 'Mélange fluide'

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