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Huff, Timothy A. "Fluid inclusion evidence for metamorphic fluid evolution in the Black Hills, South Dakota /." free to MU campus, to others for purchase, 2004. http://wwwlib.umi.com/cr/mo/fullcit?p1421144.
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Watson, Adrian Paul. "The timing and significance of quartz veins in Greenschist facies metamorphic rocks with particular reference to the Precambrian of Holy Island, Anglesey, Wales." Thesis, University of Derby, 1999. http://hdl.handle.net/10545/304840.
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Chandonais, Daniel. "Deformation and Fluid History of Late Proterozoic and Early Cambrian Rocks of the Central Appalachian Blue Ridge." Bowling Green State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1343055132.
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Bastoul, Abdelmajid. "Origine et évolution des fluides hydro-carbo-azotés dans les formations métamorphiques : relations avec les minéralisations associées (u, au, graphite)." Nancy 1, 1992. http://www.theses.fr/1992NAN10390.
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L'origine et l'évolution physico-chimiques des fluides carbo-azot2s, et la reconstitution des principaux stades de production et de migration de ces fluides, ainsi que leur rôle dans les processus metallog2niques, au cours du métamorphisme constitue l'objet principal de ce mémoire. Les travaux réalisés sur trois zones métamorphiques, au Maroc (Jebilet centrales, Tichka) et au sud-ouest du massif central français, ont permis de: 1) faire un inventaire des fluides en équilibre avec les schistes noirs et leur phase de production dans des contextes de métamorphisme de contact; 2) d'aborder le rôle de ces fluides dans le contrôle des équilibres entre fluides et minéraux; 3) de proposer une chronologie relative entre les phases de migration des fluides carbo-azotés et des fluides sans espèces volatiles, en relation avec la mise en solution et le dépôt de l'uranium (bondons), de l'or (Tichka) et du graphite (Jebilet). Ce travail basé essentiellement sur l'étude des fluides du système chons, a permis d'obtenir des résultats originaux sur: 1) le calage précis des phases de production et de migration de ces fluides en fonction de l'évolution des conditions p-t-x et des dépôts de minéraux; 2) l'utilisation de plusieurs techniques nouvelles (microspectroscopie infrarouge, microsonde nucléaire) pour la caractérisation des sites de l'azote et la quantification de sa concentration; 3) la présentation d'un modèle de la genèse des minéralisations de graphite
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Lamadrid, De Aguinaco Hector M. "Geochemistry of fluid-rock processes." Diss., Virginia Tech, 2016. http://hdl.handle.net/10919/71350.
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When these fluids interact with the surrounding rocks, small aliquots of these fluids are trapped as imperfections in the crystal lattice and fractures of minerals. These microscopic features are called fluid and melt inclusions, and are one of the best tools available to probe, measure and determine the chemical and physical properties of crustal fluids. In the present study we examine new developments into our understanding of fluid-rock interactions using fluid and melt inclusion as tools to provide insights into the evolution of the Earth's crust from the deep continental crust to the surface. Chapter II "Raman spectroscopic characterization of H2O in CO2-rich fluid inclusions in granulite facies metamorphic rocks", is a brief review of the current understanding of granulite rocks and their formation, and a new development into our ability to characterize the composition of the fluids trapped as fluid inclusions in minerals in granulite facies rocks. Chapter III "Reassessment of the Raman CO2 densimeter", details new developments in the use of the Raman spectroscopy to characterize the density of CO2. In this chapter we describe briefly the Raman effect of CO2 and the density dependence of the Fermi diad using different Raman instruments, laser sources and gratings to understand the differences in the published data. Chapter IV "Serpentinization reaction rates measured in olivine micro-batch reactors" describes new insights into the serpentinization process by using olivine micro-reactors. The micro-reactor technique is a new experimental development that allows researchers to monitor the fluid chemistry as well as the mineral composition changes inside synthetic fluid inclusion.Ph. D.
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Merceron, Thierry. "Les altérations hydrothermales de la coupole granitique d'échassières et de son environnement (sondage gpf echa n1)." Poitiers, 1988. http://www.theses.fr/1988POIT2330.
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Reconstitution chronologique de l'alteration hydrothermale du granite de beauvoir, apex granitique d'echassieres (massif central), a partir des donnees petrographiques, mineralogiques, et datations k-ar. L'etude des isotopes stables oxygene-hydrogene et des inclusions fluides a permis d'etablir un modele thermodynamique sur le refroidissement du magma granitique. Dans les micashistes ces phenomenes hydrothermaux se superposent aux alterations associees au stockwerk a wolframite de l'hypothetique granite de la bosse
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Lewerentz, Alexander. "Fluid-induced alteration of metasedimentary rocks in the Scottish Highlands." Doctoral thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-146121.
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Fluids, mainly H2O and CO2, are released from H- and C-bearing phases during prograde metamorphism. Because of the buoyancy of these fluids, they rise within the crust towards the surface of the Earth. Metamorphic fluids take advantage of permeable horizons, shear zones, fold hinges, fractures, and are channelled into high-flux zones. Fluid fluxes for channelized fluid flow may exceed background pervasive fluxes by several orders of magnitude. Metamorphic fluids react with the surrounding rock during fluid flow, and altered zones are commonly observed adjacent to high-flux conduits. Fluid-altered rock is texturally, mineralogically, chemically, and isotopically different from rock unaffected by fluid flow. In this thesis, fluid-rock interaction is studied at two localities in the Scottish Highlands: Glen Esk and the Isle of Islay. Glen Esk is one of the type localities used by George Barrow (1853-1932) to propose the concept of metamorphic zones and metamorphic index minerals as an approximate determination of metamorphic grade. In several of the metamorphic zones in Glen Esk, index mineral distribution is highly dependent on proximity to veins. The occurrence of index minerals is therefore not only controlled by pressure and temperature, but also by the availability of metamorphic fluids. Evidence of a retrograde fluid flow event from the North Esk Fault is observed in Glen Esk, for which a time-averaged fluid flux of 0.0003 – 0.0126 m3∙m-2∙yr-1 is calculated. The duration of the fluid event is estimated to between 16 and 334 kyr. On the Isle of Islay, kyanite is observed in rocks of chlorite or lower-biotite metamorphic grade, i.e. much lower temperatures than usually associated with kyanite formation. The favoured explanation for this is retrograde infiltration of extremely high-CO2 fluids, at least locally XCO2 > 0.7, at ~340°C, which altered these rocks and stabilised kyanite in a carbonate-bearing assemblage. Oxygen and carbon stable isotope profiles across the Islay Anticline reveals highly channelized fluid flow along the axial region of this fold, with fluid:rock ratios at least four times higher than in rock farther away from the fold. Although carbon and oxygen isotope ratios of metacarbonate rocks were altered along the Islay Anticline, negative anomalies observed below and above the Port Askaig Tillite Formation cannot solely be attributed to metamorphic fluid flow, which implies that these rocks to varying degree retain their primary paleoclimatological isotopic signatures.Stora volymer H2O och CO2 frigörs som fluider under prograd metamorfos. Metamorfa fluider har lägre densitet än det omgivande berget, varför de stiger genom jordskorpan mot jordytan. Metamorfa fluider kanaliseras i permabla lager, skjuvzoner, veckaxlar, sprickor och andra högflödeszoner. Kanaliserade fluidflöden kan vara flera storleksordningar högre än bakgrundsvärdet för fluidflöde inom en bergart. Metamorfa fluider reagerar under transport med det omgivande berget och bildar fluidomvandlade zoner i anslutning till högflödeskanaler. Fluidomvandlat berg uppvisar texturella, mineralogiska, kemiska och isotopsammansättningsmässiga skillnader i jämförelse med berg som inte utsatts för fluidomvandling. I denna avhandling behandlas reaktioner mellan fluid och berg som studerats i två lokaler i de skotska högländerna: Glen Esk och Islay. Glen Esk är en av de typlokaler som George Barrow (1853-1932) använde för att lägga fram konceptet om metamorfa zoner och metamorfa indexmineral som används för att ungefärligt uppskatta metamorf grad. I flera av de metamorfa zonerna är förekomsten av indexmineral i hög grad beroende av närhet till kvartsådror, vilket visar att bildandet av indexmineral inte bara styrs av tryck och temperatur, utan också av åtkomst till metamorfa fluider. I Glen Esk finns också spår av ett fluidflöde från North Esk-förkastningen, under retrograda metamorfa förhållanden, för vilket mededfluidflödet över tid uppgår till 0.0003 – 0.0126 m3∙m-2∙år-1. Denna fluidflödeshändelse beräknas ha pågått mellan 16 000 och 334 000 år. På ön Islay i de sydvästra högländerna återfinns bergarter, som trots sin låga metamorfa grad i klorit- eller biotitzonen innehåller mineralet kyanit, dvs. temperaturer långt under vad som vanligen associeras med kyanitbildning. Detta förklaras med infiltration av fluider med extremt hög CO2-halt, åtminstone lokalt så högt som XCO2 > 0.7, vid ca. 340°C. Fluidomvandling av dessa bergarter stabiliserade kyanit tillsammans med karbonatmineral. Syre- och kolisotopprofiler över Islayantiklinen påvisar hög kanalisering av fluider längs dess veckaxeln. Förhållandet mellan fluid och berg var mer än fyra gånger så högt i närheten av veckaxeln jämfört lokaler längre ifrån densamma. Påverkan av metakarbonatbergarters isotopförhållanden har skett längs Islayantiklinen, men fluidpåverkan kan inte ensamt förklara de isotopanomalier som observerats under och ovan Port Askaig-tilliten, varför dessa bergarter kan ha bibehållit sin primära paleoklimatologiska isotopsignatur.
At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 3: Manuscript.
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Rafaranalisoa, Esther. "Donnees nouvelles sur la hibonite (ca a112 o19) de madagascar." Paris 6, 1988. http://www.theses.fr/1988PA066502.
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Apres un historique de la roche a hibonite de madagascar et un resume de son etude par curien et al (1956) ainsi que des autres hibonites : urss, tanzanie et meteoritiques, on presente l'etude petrograhique et chimique des plagioclasites a hibonite qui sont comparees aux sakenites de lacroix. Le chapitre 4 est consacre a la chimie, la structure et l'interpretation des substitutions possibles dans ce mineral;les deux derniers chapitres s'attachent aux etudes des inclusions fluides dans le corindon et des inclusions solides dans les differents mineraux constituant la plagioclasite a hibonite.
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Kleine, Barbara I. "How do metamorphic fluids move through rocks? : An investigation of timescales, infiltration mechanisms and mineralogical controls." Doctoral thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-115172.
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This thesis aims to provide a better understanding of the role of mountain building in the carbon cycle. The amount of CO2 released into the atmosphere due to metamorphic processes is largely unknown. To constrain the quantity of CO2 released, fluid-driven reactions in metamorphic rocks can be studied by tracking fluid-rock interactions along ancient fluid flow pathways. The thesis is divided into two parts: 1) modeling of fluid flow rates and durations within shear zones and fractures during greenschist- and blueschist-facies metamorphism and 2) the assessment of possible mechanisms of fluid infiltration into rocks during greenschist- to epidote-amphibolite-facies metamorphism and controlling chemical and mineralogical factors of reaction front propagation. On the island Syros, Greece, fluid-rock interaction was examined along a shear zone and within brittle fractures to calculate fluid flux rates, flow velocities and durations. Petrological, geochemical and thermodynamic evidence show that the flux of CO2-bearing fluids along the shear zone was 100-2000 times larger than the fluid flux in the surrounding rocks. The time-averaged fluid flow velocity and flow duration along brittle fractures was calculated by using a governing equation for one-dimensional transport (advection and diffusion) and field-based parameterization. This study shows that fluid flow along fractures on Syros was rapid and short lived. Mechanisms and controlling factors of fluid infiltration were studied in greenschist- to epidote-amphibolite-facies metabasalts in SW Scotland. Fluid infiltration into metabasaltic sills was unassisted by deformation and occurred along grain boundaries of hydrous minerals (e.g. amphibole) while other minerals (e.g. quartz) prevent fluid infiltration. Petrological, mineralogical and chemical studies of the sills show that the availability of reactant minerals and mechanical factors, e.g. volume change in epidote, are primary controls of reaction front propagation.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript. Paper 4: Manuscript.
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Kleine, Barbara. "How do fluids move through rocks? : High fluxes of CO2 in the Earth's crust." Licentiate thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-84007.
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Metamorphic hydrous, CO2-bearing fluids play a critical role in the global carbon cycle. However, how big this influence is on the global carbon cycle and therefore on global climatic processes, is unknown. The actual amount of CO2 which is released into the atmosphere due to metamorphic processes is still debated. For this purpose, fluid-driven reactions in metamorphic rocks must be studied by tracking fluid-rock interactions along pathways of ancient fluids. In the study presented in this thesis, we study fluid-rock interaction in the southeastern part of the Greek island Syros in the Cycladic Archipelago (Aegean). On Syros fluid-rock interaction is recorded by the preservation of blueschist facies assemblages at greenschist facies conditions along a normal shear zone. Blueschist preservation is caused by a combination of metasomatic addition of SiO2 and Na2O and elevated XCO2 which is maintained by high fluxes of a CO2-bearing, hydrous fluid along the shear zone. This research aims to provide a better understanding of the role of mountain building in the carbon cycle. Flux estimates for climate-forcing fluid components (e.g. carbon) require that their concentration in the fluid, fluid volumes and velocities are known. This will be the focus of future work. Further, whole rock chemistry and the availability of specific minerals will be studied to achieve knowledge about which kind of parameters influence and enhance the propagation of fluids through rocks.
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Holness, Marian Barbara. "Experimental and petrological studies of textural equilibrium and fluid flow in metacarbonate rocks : the Beinn an Dubhaich Aureole, Skye." Thesis, University of Cambridge, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.385419.
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Cui, Xiaojun. "Numerical modeling of reactive fluid flow in the Notch Peak contact metamorphic aureole, Utah /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060092.
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Mulder, Ines [Verfasser], and Heinz Friedrich [Akademischer Betreuer] Schöler. "Volatile Organohalogens from Fluid Inclusions of Rocks and Minerals / Ines Mulder ; Betreuer: Heinz Friedrich Schöler." Heidelberg : Universitätsbibliothek Heidelberg, 2015. http://d-nb.info/1180395077/34.
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Rougvie, James Russell. "Metamorphism in the northern Park Range of Colorado : fluid-rock interactions and thermobarometry /." Digital version accessible at:, 1999. http://wwwlib.umi.com/cr/utexas/main.
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Henry, Adam T. "Petrologic and Fluid Inclusion Constraints on the Tectonic Evolution of the Manhattan Prong, Southeastern New York." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/36855.
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The results of a combined mineral equilibria and fluid inclusion study show that the Manhattan Prong, southeastern New York, has experienced multiple metamorphic events. Two episodes of intrusion, separated by approximately 100 million years, have superimposed contact aureoles on the Taconic regional metamorphic gradient in the northeastern Manhattan Prong and have modified the regional assemblage to different degrees.
The assemblage Sil-Bt-Grt-Qtz-Pl+Ksp+Ms in regionally metamorphosed Manhattan Schist records P-T conditions of 4-5 kbar and 650-700 oC. Garnet porphyroblasts, homogenous with respect to major elements but zoned with respect to P and Y, contain ubiquitous, primary, CO2-rich fluid inclusions which have a Th = 10-24 oC. Manhattan Schist collected adjacent to the Croton Falls and Peach Lake mafic complexes, intrusions thought to be related to the Late Ordovician Cortlandt Complex, record P-T estimates of 4 kbar and 700 oC and 4.2 kbar and 550-600 oC respectively. The lack of fluid inclusions in garnet porphyroblasts indicates that the regional metamorphic assemblage has been completely modified by the contact effects of the mafic intrusions. However, the presence of Ky+Sta along with the slight compositional zoning of garnets in Peach Lake samples suggests that the contact assemblage may have been modified by a later metamorphism.
Manhattan Schist collected adjacent to ~350 Ma granites (Brock, 1993) has been partially modified by contact metamorphism and shearing but vestiges of the regional metamorphic assemblage remain. Garnet porphyroblasts contain abundant CO2-rich fluid inclusions and P-T estimates using Bt and Pl inclusions and garnet core compositions are similar to estimates of regional metamorphic conditions. Evidence of modification includes garnet overgrowths that are elevated in Ca and depleted in Mn, Y and Sc, and CO2-rich fluid inclusions that have reequilibrated to higher density (Th = 2-18 oC). Rim compositions of porphyroblasts yield P-T estimates of 5-6 kbar and 550-600 oC. The elevated Ca content of the overgrowths along with the presence of Ky in the matrix suggests that the reaction An = Ky + Grs + Qtz may have been active during the overprinting metamorphism.
The increase in pressure recorded in the granite aureoles in the Manhattan Prong is inconsistent with the results of P-T studies of the Rowe-Hawley belt, approximately 20 km to the east across Cameron's Line. This suggests that these two terranes may have been separated in the Devonian.Master of Science
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Higashino, Fumiko. "Infiltration process of brine in the deep crust constrained from multi-scale major and trace element zonings in high-grade metamorphic rocks." 京都大学 (Kyoto University), 2016. http://hdl.handle.net/2433/215324.
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Matsumoto, Keisaku. "Petrological study of high-pressure metamorphic rocks in the Sesia zone, western Alps : the role of lawsonite on the fluid activity in the subduction zone." 京都大学 (Kyoto University), 2007. http://hdl.handle.net/2433/136782.
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Engström, Adam. "Metal mobility during metamorphism and formation of orogenic gold deposits: Insights from the Dalradian of Scotland." Thesis, Stockholms universitet, Institutionen för geologiska vetenskaper, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-92297.
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Orogenic gold deposits occur within metamorphic belts throughout the world and have through time represented the source for over 25% of the world’s gold production. Although orogenic gold deposits are of great economic importance, controversies exist on the subject of fluid and metal sources and there have been few studies of gold´s distribution and mobility outside of large economic deposits. Research made by Pitcairn et al. (2006), on the Mesozoic Otago and Alpine schists of New Zealand, observed systematic depletion of Au and a suite of 6 associated elements with increasing metamorphic grade. This depletion was identical to the suite of elements enriched in the Otago gold deposits and provided strong evidence that orogenic gold deposits form due to metamorphic processes. The mobilization of metals was attributed to the recrystallization of sulfide minerals during prograde metamorphism causing dehydration and release of metal-rich metamorphic fluids. This thesis is part of a larger project aimed at testing the “Otago model” in a classic metamorphic terrain: The Dalradian metamorphic belt of Scotland. Rocks in the study are from the southern higlands group and the Appin and Argyll group which range in metamorphic grade from chlorite zone greenschist facies to sillimanite zone amphibolite facies. Three main aspects, which supplement earlier research, are addressed in this study: 1) Investigation of the sulfide paragenesis at Loch Lomond and Stonehaven was carried out to map the evolution of sulfides with metamorphic grade and the possible relations to the distribution of gold. Using SEM scanning to quantify the abundance of different sulfide minerals together with previous data on the Glen Esk region, a complex sulfide evolution pattern for the Dalradian Supergroup is identified. The sulfide evolution describes the same changes in texture and chemistry as observed in the Otago Schists but is made complex by the difference in geological evolution for the different regions. 2) Reinvestigation of the higher grade zones of Glen Esk (staurolite to sillimanite) was carried out as samples from the previous study were very weathered. Results from ultralow detection limit methods (HG-AFS and a gold detection method developed by Pitcairn et al. 2006) showed significant systematic depletion of Au and As with metamorphic grade. From chlorite to sillimanite zone average values of Au and As were showed to decrease by 65% and 88% respectively. Furthermore, a suite of 10 major and 12 trace elements were analyzed using ICP methods showing no trends of systematic depletion with increased metamorphic grade. 3) Investigation of Pb-Ag Veining and vein samples from each of the metamorphic index mineral zones in the Glen Esk area was carried out to identify fluid composition and ore mineralogy. Using microthermometry and Raman laser spectroscopy two distinct fluids were identified. The first type is a H2O-CO2-N2-salt fluid of low salinity (0-15 weight percent NaCl equivalent) and medium temperature (150 to 250 °C) locally containing minor amounts of CH4. It is found in the veins from the mineral index zones of Glen Esk and was formed in the ductile regime most likely related to late stage metamorphic devolatilization released during Caledonian uplift of the Dalradian. Pb-Ag veins from the locality of Hardhill host the second fluid type which was formed in the brittle regime accompanied by brecciation as a high salinity (15 to 20 weight percent NaCl equivalent) low temperature (70-140°C) H2O-salt fluid with calcic composition was precipitated. This fluid bears much resemblance to Carboniferous calcic brines responsible for economic base-metal precipitation with widespread occurrence in southwest Scotland and Northern Ireland. Results of this thesis show many similarities with the Otago study, with a connection between metal mobility and metamorphic grade, providing support for the dehydration model as a viable mechanism for the generation of orogenic gold deposits.
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Dyja, Vanessa. "Interaction entre fluides de différents réservoirs lors de l'évolution d'un prisme orogénique en contexte de déformation partitionnée : les Cordillères bétiques internes (Espagne) : Implications sur le transfert de métaux dans la croute." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0029/document.
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La thèse cherche à caractériser les types de fluides à différents niveaux structuraux et types de déformation. Les résultats de la Sierra Bédar indiquent le rôle d'une saumure enrichie en métaux lors des derniers stades de circulation au sein de la croûte ductile dans un domaine encore isolé des fluides de surface. Cette saumure est plus diluée à l'est dans la Sierra Almagrera et où l'impact du système décrochant va devenir de plus en plus important avec du volcanisme et de nombreux gisements. Dans le domaine fragile, des veines de quartz enregistrent des fluides de surface. Suivent des veines de quartz indiquant la réapparition des fluides métamorphiques sous-jacent. La formation de veines de sidérite-pyrite-galène-barytine montre de plus forte salinité et des rapports Cl/Br indiquant la contribution d'une autre source de saumures secondaires issues cette fois des évaporites messiniennes. Le décrochement a modifié le compartimentage de part et d'autre de la transition fragile-ductileThis thesis aim at characterizing the types of fluids concerned structural levels and style of deformation. Results from Sierra Bedar point out the role played by metal-rich brines during late stages of fluid flows within the ductile crust within a domain was still isolated from surficial fluids. Brine concentration drop in the eastern Sierra Almagrera which was progressively more impacted by the major transcurrent system with volcanism and metal ore deposits. At reaching the brittle domain, quartz veins trapped surficial fluids. Soon after, quartz veins indicating the return of metamorphic fluids. Following siderite-pyrite-galena-barite veins display higher salinities and Cl/Br ratios indicate the contribution of another secondary brine coming from early Messinian evaporites. This major transcurrent tectonics clearly modified the partitioning on both sides of the brittle-ductile transition
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Albrecht, Nina. "Metamorphic fluids at extreme pressure conditions and their significance for element transfer in subduction zones." Doctoral thesis, 2017. http://hdl.handle.net/11858/00-1735-0000-0023-3E42-C.
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Feldtmann, Franette. "The structural-metamorphic evolution of the marble and calc-silicate rocks of the Baklykraal quarry near Alldays, Central Zone, Limpopo Belt, South Africa." Thesis, 2012. http://hdl.handle.net/10210/6756.
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Fox, Don. "Structure, metamorphism and tectonic setting of metasedimentary rocks and mafic-ultramafic inclusions in the Dashwoods subzone of the Dunnage zone, southwestern Newfoundland /." 1992. http://collections.mun.ca/u?/theses,75451.
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Saunders, Brenton Mark. "Fluid-induced charnockite formation post-dating prograde granulite facies anatexis in southern Natal metamorphic province, South Africa." Thesis, 2014. http://hdl.handle.net/10210/10370.
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M.Sc. (Geology)The Proterozoic Namaqua-Natal Mobile Belt of southern Africa represents a succession of high grade metamorphosed igneous and sedimentary rocks rimming the southern and western extents of the Kaapvaal craton. Different petrological processes associated with the onset of granulite facies metamorphism were investigated with the emphasis on the processes on anatexis and migmatitization and the influence of the fluid phase on these processes. The investigation took place in the Margate Terrane of the Southern Natal Metamorphic Province. The Umzimkulu and Louisiana Quarries near Port Shepstone formed the bulk of the field area for this investigation. The Umzimkulu and Louisiana quarries expose two s-type granitic lithologies, namely, the Glenmore Biotite Gneiss (GBGn) and the slightly younger, intrusive Margate Leucogranite (MLGn), both of which have been metamorphosed to granulite facies. Geothermobarometric calculations on the metamorphism of the Margate Terrane all indicate temperatures and pressures of peak metamorphism be 850oC+50oC at +6 kbar. The high grade metamorphic history of the lithologies is recorded by the formation of concordant, lens-shaped, prograde anatectic leucosomes. The leucosomes are concentrically surrounded by biotite selvage zones, followed by melanosomes, and lastly undisturbed host rock material. This investigation revealed that the formation of both the charnockite veins and the prograde leucosomes occurred through processes of anatexis. Field relations suggest that the charnockitic veins formed in situ, and were structurally controlled, which is evident from their linearity. Petrographic and geochemical data provide evidence for melt involvement. This is in strong contrast to theories of charnockite formation ascribed to subsolidus granulite formation by the flushing of host lithologies by a pervasive, carbonic fluid, as has been suggested to have occurred in Southern India. The so-called "incipient charnockites" of Southern India are both morphologically and geochemically similar to the charnockite veins described in the SNMP, suggesting that an anatectic origin may be common to both.
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Mancini, Laura. "Diagenesis of middle Ordovician rocks from the Lake Simcoe area, south-central Ontario." Thesis, 2011. http://hdl.handle.net/10012/6340.
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Middle Ordovician carbonates in the Lake Simcoe area, south-central Ontario were examined to determine if: (1) The δ18O values of early-stage calcite cement in hardgrounds are useful proxies for Ordovician seawater δ18O values; (2) a regional hydrothermal event affected middle Ordovician strata in the Lake Simcoe area. Whole rock samples of middle Ordovician hardgrounds and immediately overlying limestones containing early calcite cement have δ13C values ranging from -1.7 to +2.9‰ (PDB) and δ18O values ranging from -6.9 to -2.9‰ (PDB). Hardground δ18O values and the similarity of the isotopic composition between the hardgrounds and overlying limestones are consistent with diagenetic alteration during shallow burial, which indicates the hardgrounds are not useful proxies. Late-stage calcite cements have δ13C values from -8.4 to +2.9‰ (PDB) and δ18O values from -11.4 to -6.0‰ (PDB). Late-stage microcrystalline dolomites have δ13C values from -3.9 to +0.4‰ and δ18O values from -10.7 to -7.6‰. Late-stage saddle dolomites have δ13C values from -1.7 to 1.9‰ and δ18O values from -13.8 to -8.5‰. The late-stage carbonate δ18O values are more negative than the early-stage carbonate δ18O values and are interpreted to reflect progressively deeper burial diagenesis.
Four types of fluid inclusions were identified in late-stage calcite, saddle dolomite, barite, and quartz. Type 1 inclusions are aqueous liquid-rich with very consistent low to very low vapour-liquid ratios and are of primary, secondary pseudosecondary and indeterminate origins. Type 2 inclusions are aqueous liquid-only and are of primary and secondary origins. Type 3 inclusions are oil-bearing, liquid-rich with low to medium vapor-liquid ratios and are of secondary origin. Type 4 inclusions are vapour-only and are of indeterminate origin. The type 4 inclusions analyzed did not yield any microthermometric data suggesting they are empty cavities that have lost all their fluid.
Fluid inclusions of primary, secondary and pseudosecondary origins in calcite, dolomite and quartz have overlapping homogenization temperatures ranging from 43 to 188°C. Fluid inclusions of indeterminate origin in calcite and barite have homogenization temperatures from 80 to greater than 200°C. Petrographic and microthermometric evidence indicates that fluid inclusion homogenization temperatures greater than 150°C most likely are caused by stretching or leaking; therefore, are discounted. Fluid inclusion types 1 and 2 represent two fluid inclusion assemblages (FIA) based on final ice melting temperatures. The high salinity (10 to 30 wt%CaCl2) inclusions in FIA 1 are of primary, secondary, pseudosecondary and indeterminate origin in calcite, dolomite, barite and quartz. Fluid inclusions in FIA 1 are interpreted as reflecting saline basin brines from which the host minerals precipitated during burial diagenesis. The low salinity (0 to 2.7 wt%CaCl2) inclusions in FIA 2 are of secondary and indeterminate origin in calcite. Fluid inclusions in FIA 2 may reflect a meteoric origin such as in a vadose or phreatic environment based on inclusions containing different phases and variable vapor-liquid ratios. Alternatively the low salinity inclusions may reflect alteration from an influx of meteoric fluids that migrated through basement faults and fractures during periods of uplift and erosion.
Early and late-stage carbonates from this study precipitated from 18O-depleted pore fluids and/or at progressively higher temperatures accompanying deeper burial. The FIA 1 homogenization temperatures support burial diagenesis at 66 to 80°C if it is assumed the rocks were buried 2 km, the surface temperature was 20°C and the geothermal gradient was between 23 to 30°C/km.
An alternative interpretation is mineral precipitation during a regional hydrothermal event. Burial diagenesis does not explain the fluid inclusion homogenization temperatures of 90°C and greater unless geothermal gradients are higher than 35°C/km or burial depth is increased to 3 km or more. However, thermal maturity of organic matter in the Michigan Basin suggests Ordovician strata were never buried more than 2 km. Four models for regional hydrothermal fluid migration are: (1) gravity-driven flow; (2) ‘squeegee-type’ fluid flow; (3) convection cell fluid flow; and (4) structurally-controlled fluid flow. The gravity-driven model relies on continental heat flow and an influx of meteoric water from basin catchment areas. For the ‘squeegee, convection cell and structurally controlled models, hot fluids could have entered the region from several conduits concurrently during episodic reactivation of basement faults and fracture systems in response to intracratonic stresses created by the continuous interaction of tectonic plates. Determining which of the models best explains regional hydrothermal fluid flow in the Michigan Basin is difficult for several reasons; (1) surface temperatures and maximum burial temperatures at the time of mineral precipitation in the Michigan Basin during the Ordovician are unknown; (2) the timing of mineral precipitation in relation to tectonic pulses is undetermined; (3) there is as yet no known deep-seated heat sources in the Michigan Basin for convection to occur; and (4) it is unknown whether advection is a major process in the Michigan Basin. A collaborative multi-disciplinary research project covering geology, geophysics and hydrogeology would provide much more integrated data than is currently available from stable isotopes, fluid inclusions and organic matter.
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Schaefer, Markus Olaf. "Paleoproterozoic Mississippi Valley-Type Pb-Zn deposits of the Ghaap Group, Transvaal Supergroup in Griqualand West, South Africa." Thesis, 2009. http://hdl.handle.net/10210/1969.
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Bubal, Jan. "Geochemie a vznik skarnů Českého masivu." Master's thesis, 2013. http://www.nusl.cz/ntk/nusl-321074.
Full textAbstract:
Calcic-iron skarns are one of the characteristic part of the regional metamorphic complexes of the Bohemian Massif. Their mineral assemblages, structures and significant enrichment of Ca, Al and Fe were previously interpreted to be primary (exhalation sediment) or secondary (metasomatic carbonates). In this project, which consists of three sub-studies will focus on the geochemical composition of skarn as the main arguments for the discussion of their origin. Malešov deposit belongs to the typical calcic-iron skarns whose mineral assemblages are not very different from similar skarns associations in the Bohemian massif. It consists of lenticular body that is stored in gneiss and migmatites of the Kutná Hora crystalline complex. On the deposit prevails garnet-pyroxen skarn, less abundantly represented garnet and magnetite skarns and skarns replacement by amphibole or epidote. Fine-grained garnet skarns are formed by isotropic dark red garnet (Adr78-88Prp0-0.3), while in massive garnet rocks garnet grains form the core (Adr13-38Prp2.5), which envelop newly formed garnet (Adr28-66Prp1.6). In association with them is often pyroxene (Hd60-90) which can be replaced by hastingsite amphibole composition. Other minerals present are magnetite, Fe-epidote, calcite and albite. Magnetite and pyroxene skarns are...