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1
Henrique-Pinto, Renato. "Metaconglomerados e rochas associadas do Grupo São Roque a noroeste da cidade de São Paulo: proveniência e implicações para a idade da sedimentação." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/44/44143/tde-11112008-115527/.
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O Grupo São Roque caracteriza-se por rochas de baixo grau metamórfico, depositadas em ambiente marinho com atividade vulcânica submarina. As ocorrências da Formação Morro Doce são dominadas por metarcóseos e metarenitos feldspáticos com expressivas lentes metaconglomeráticas, que formam uma seqüência considerada como unidade basal do Grupo São Roque. Os metaconglomerados, com o amplo predomínio de clastos graníticos, têm excelente potencial para identificação de suas fontes e idades. Rochas metavulcânicas ácidas e básicas intercaladas nesta seqüência constituem importante marcador tectônico e cronológico. O estudo petrográfico dos clastos graníticos dos metaconglomerados da Formação Morro Doce permitiu a identificação de quatro variedades petrográficas: biotita monzogranito porfirítico, biotita monzogranito inequigranular, biotita monzogranito equigranular e leucogranito inequigranular. O caráter comagmático entre os clastos é confirmado pelos dados petrográficos e geoquímicos. Rochas metavulcânicas ácidas que ocorrem intercaladas a metarcóseos e metaconglomerados, na região do Morro do Polvilho, correspondem a meta-traquidacitos e metariolitos porfiríticos. Os metarcóseos mostram afinidades geoquímicas com os clastos de granito dos metaconglomerados, e diferenciam-se das rochas metavulcânicas ácidas associadas pela geoquímica e pela petrotrama sedimentar composta predominantemente por feldspatos detríticos sub-angulosos. De características geoquímicas típicas de magmatismo intraplaca, em especial baixo mg# (~20), altos teores de Zr (560-730 ppm), Y e Nb, além de baixo Sr (70-120 ppm), as rochas metavulcânicas ácidas do Grupo São Roque apresentam similaridades com as metavulcânicas ácidas da base do Supergrupo Espinhaço. Datações U-Pb por LA-MC-ICP-MS em cristais de zircão extraídos das variedades predominantes de seixos graníticos revelaram idades Paleoproterozóicas (2199 ± 8.5 Ma e 2247 ± 13 Ma). Idades comparáveis só são encontradas regionalmente em núcleos do embasamento do Supergrupo Espinhaço (Complexo Mantiqueira) e Açungui (núcleos Tigre, Setuva e Betari). A idade de deposição dos metaconglomerados (1.75-1.79 Ga), indicada pelas datações U-Pb em rochas metavulcânicas intercaladas é consistente com a idade dos clastos (granito fonte), datados em 2.2 Ga, e com a ausência de indicações de contribuições de áreas-fontes mais jovens para os metassedimentos da Fm. Morro Doce.The São Roque Group is composed of low-grade metamorphic rocks deposited in marine environment with coeval volcanic activity. The Morro Doce Formation is dominated by metaarkose and feldspatic meta-sandstone with expressive metaconglomeratic lenses, which form a sequence regarded as the basal unit of São Roque Group. The metaconglomerates with wide prevalence of granite pebbles have excellent potential to identify their sources and ages. Metavolcanic acidic and basic rocks interspersed in this sequence are an important tectonic and geochronologic marker. The petrographic study of the granite pebbles from the Morro Doce Formation metaconglomerates allowed the identification of four petrographic varieties: porphyritic biotite monzogranite, inequigranular biotite monzogranite, equigranular biotite monzogranite and inequigranular leucogranite. The comagmatic character of these pebbles is confirmed by petrographic and geochemical data. Acid metavolcanic rocks interlayered with meta-arkose and metaconglomerates in the Morro do Polvilho region correspond to trachydacite and porphyritic meta-rhyolite. The metaarkose shows geochemical affinities with metaconglomerate granitic pebbles, and differs from the acid metavolcanic rocks both in their geochemical signature and in its sedimentary fabrics defined by the predominance of detritic subangulous feldspars. Their geochemical characteristics are typical of within-plate magmatism, especially the low mg # (~ 20), high Zr (560-730 ppm), Y, Nb, and low Sr (70-120 ppm), and is similar to the acid metavolcanics from the on Espinhaço Supergroup. U-Pb dating by LA-MC-ICP-MS in zircon crystals from the predominant varieties of granitic pebbles revealed Paleoproterozoic ages (2199 ± 8.5 Ma Ma and 2247 ± 13) for the main granitic source of the metaconglomerates. Comparable ages are found in the nuclei of Espinhaço Supergrup basament (Mantiqueira Complex) and Açungui (Tigre, Setuva and Betari nuclei). The depositional age of the metaconglomerates (1.75-1.79 Ga), indicated by U-Pb dating of interlayered metavolcanic rocks, is consistent with the age of the granitic source, (~2.2 Ga), and with the lack of signals of contribution from younger source areas for the Morro Doce Fm metasediments.
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Yang, Wenjin. "Géochimie et minéralogie des granites de la région de Hetai, province de Guangdong, Chine méridionale = Geochemistry and mineralogy of granites in the Hetai area, Guangdong, South China /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.
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Thèse (D.R.Min.)-- Université du Québec à Chicoutimi, 1993.Thèse presentee en collaboration de l'Université du Quebec à Chicoutimi et Institute of geochemistry, Academia Sinica, China. CaQCU Document électronique également accessible en format PDF. CaQCU
3
Awoleye, Olumuyiwa Adebayo. "Weathering and iron oxide mineralogy of Hong Kong granite." Thesis, University of Glasgow, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.318702.
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Oak, Keith Alan. "The geology and geochemistry of Closepet granite, Karnataka, South India." Thesis, Oxford Brookes University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278897.
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The Archaean craton of southern India has four main components. The multi-phase Peninsular gneiss, with ages from 3360-2900 Ma, is spatially dominant and grades from granulite facies in the south to greenschist facies in the north. Ages for the Peninsular gneiss range from 3360-2900 Ma. Within the craton are two suites of Greenstone Belts and supracrustal rocks. The older, high-grade Sargur type occur as enclaves in the Peninsular gneiss and are in places older than 3360 Ma. The younger, lower-grade type occur occasionally have unconformable bases with the Peninsular gneiss and have been dated from 3100-2605 Ma. Granitoids form the last major component with the Closepet granite being the largest, ages for the emplacement of the Closepet granite and many of the other granitoids cluster around 2500 Ma. The Closepet granite outcrops from Kabbal Durge in the south to the Deccan Plateau in the north, a distance of some 450 km. A 320 km section from Kabbal Durga to Hospet in the north exposes a linear trending granite. The granite outcrop varies from one of essentially partial melting and melt extraction in the south to a zone of melt accumulation in the central zone to a zone of high level intrusion of large granite bodies. Related to these changes in primary processes are changes in the granite phases, size, shape and intrusive style. The petrography of the granite phases is described. These studies help to constrain phase relationships. The petrography also provides evidence to suggest that the K-feldspar megacrysts are in fact phenocrysts. Analyses of major and trace elements utilised standard X.R.F. methods. However, the analyses of REE on selected samples involved the setting up of the department's "ICP for routine operation. This procedure is outlined. The geochemistry of the granite's is described melting and crystallization models being used to explain their petrogenesis. Harker diagrams indicate that plagioclase, sphene and apatite have strong controls on major element composition and that biotite was a residual or fractionating phase. The removal of restite biotite as granite magmas intrude is thought to be a significant process.Evidence from the petrography agrees with the equilibrium phase diagram at PH2 0 ~ 5 kbar. Plots of Peninsular gneiss in the granite phase diagram have a range of compositions which could provide minimum and non-minimum melts capable of producing the Closepet granite trend. Predicted fractional crystallization would produce a sequence of magma compositions comparable to those of the Closepet granite with an order of phase crystallization that agrees with petrographic evidence. The phase relationships further constrain subsequent melting and crystallization models utilising trace elements and REE.
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McLaughlin, Richard M. "Boron and strontium isotope study of fluids situated in fractured and unfractured rock of the Lac du Bonnet Batholith, eastern Manitoba." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape11/PQDD_0007/NQ42753.pdf.
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Dewu, Bala Bellow Muhammad. "Distribution of uranium in granites and mobility of uranium during low-temperature alteration processes." Thesis, University of Exeter, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.236543.
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Mahmood, Layla A. "Mineralogy, petrology and geochemistry of some zoned dioritic complexes in Scotland." Thesis, University of St Andrews, 1986. http://hdl.handle.net/10023/15475.
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This study is an investigation into the nature and causes of petrological zonation in calc-alkaline diorite-granite plutons from the Newer granites of the Caledonian orogeny in Scotland. Six plutons were used for the study, namely Garabal Hill-Glen Fyne in the western Highlands, Glen Tilt and Glen Doll in the eastern Highlands, Comrie in the southern Highlands, and Carsphairn and Loch Doon in the Southern Uplands. The petrological zoning is concentric in the Southern Uplands and Comrie and irregular in the other three. The approach has been to acquire data on the petrography, mineral chemistry, and whole rock major and trace element chemistry for representative rock types of the petrological range within each pluton. Variations in mineral compositions are related to equilibrium crystallisation processes and indicate falling crystallisation temperatures with evolving magma composition. Mineral compositions have also been used in chemical models used to explain the observed wide variations in whole rock major oxide compositions. These models are then independently tested using models of trace element behaviour. The principal conclusions are that the main variations within the gabbro-diorite series (including cumulate peridotites and pyroxenites) are best explained by processes of fractional crystallisation from a parental gabbro or diorite magma, but in some cases the more evolved rocks (granites and granodiorites) have a more complex origin including possibly contamination of the parental magma or a distinctive magma source. The assemblage of fractionating minerals in the Garabal Hill, Comrie and Loch Doon plutons is dominated by the relatively anhydrous assemblage of orthopyroxene, clinopyroxene, plagioclase, and biotite whereas in Glen Doll it is a more hydrous assemblage dominated by amphibole. Processes of magma mixing and multi-source pulses are considered appropriate in a few cases. Regional comparisons of the within-pluton compositional variations reveal significant differences. The dominantly calc-alkaline trend shows marked differences in Fe/Mg between plutons as do trace element abundances, reflecting both differences in source region compositions and the influence of fractionating mineral phases. All plutons are I-type and high-K calc-alkaline. Parental magmas for the gabbro-diorite series have features of mantle-derived magmas though the more evolved rock types including granodiorites and granites indicate a significant contribution by crustal anatexis to the magmas.
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Wong, Ping-mei Jean. "Geochemistry, U-Pb and Sr-Nd-Hf isotopes of the Baijuhuajian A-type granites in Zhejiang Province evidence for a continuous extensional regime in the mid and late mesozoic /." Click to view the E-thesis via HKUTO, 2007. http://sunzi.lib.hku.hk/HKUTO/record/B39557297.
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Arnold, Andrew Herbert. "Geologic Implications of a Geo-Chemical Study of Three Two-Mica Granites in Southern Arizona." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/231236.
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The biotite + muscovite ± garnet-bearing Texas Canyon (TC), Presumido Peak (PP), and Gunnery Range (GR) granites are members of an enigmatic suite of Eocene age granites in southern Arizona. The late orogenic granites intrude Precambrian through Jurassic metasediments and metavolcanics. The major and minor element geochemistry of the high silica, weakly peraluminous granites is rather uniform. However, trace element concentrations, REE patterns, and isotopic compositions imply gross similarities between the TC and GR granites when both are compared to the PP granite. The TC and GR granites were derived from a depleted Precambrian lower crustal source area with low Rb/Sr, while the PP granite was the result of anatectic melting of an enriched Precambrian mid-to-upper crustal source. The PP granite is an integral part of a metamorphic core complex, and this tectonic setting accounts for the geochemical differences between it and both the TC and GR granites.
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Miller, Martin Fitzhardinge. "Geochemical and isotopic characteristics of palaeo-hydrothermal fluids related to granite magmatism, S.W. England." Thesis, Open University, 1994. http://oro.open.ac.uk/57443/.
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An assessment of stepped heating procedures for the extraction and isolation of carbonaceous species from fluid inclusions resulted in the development of low-blank procedures which permitted Sl3C characterisation of palreofluid CO2 (down to nanomole quantities) with an accuracy approaching that of the corresponding analytical precision. Similar procedures were successfully applied to the ol5N measurement of palreofluid nitrogen at the sub-nanomole level. An investigation into the origin of fluids which characterised the earliest episodes of palreohydrothermal activity associated with the granites of S W England indicates that the abundance of trace carbon species (C02 , CH4 ) and nitrogen in the fluids was correlated with the metasedimentary contribution to the respective granite source. Furthermore, SiSN and ol3C data (obtained on fluid components and local Palreozoic metasediments, in conjunction with published ol5N values of Cornubian granites), indicate that carbon and nitrogen in the hydrothermal systems were derived from the granite magmas. The chemical composition of the early hydrothermal fluids, together with geochemical and isotopic constraints from the characterisation of Palreozoic metasedimentary country rocks, support the view that the fluids were genetically associated with the granites. Fluid interaction with the local metasedimentary rocks at a high level crustal appears to have been very limited. The incorporation of sedimentary matter into granitic protoliths during anatexis, with subsequent transfer to an exsolved hydrous phase during pluton cooling, is the most probable route by which palreofluid solutes entered the early hydrothermal systems. Hydrogen stable isotope data, measured on the extracted palreowaters, indicate that meteoric water was not a significant component of early hydrothermal systems associated with either the Dartmoor granite or the nearby Hemerdon Ball intrusive, if sub-solidus isotopic exchange was significant. In contrast, comparable data from early fluids associated with other component intrusives of the batholith (as characterised by W ± Sn oxide paragenesis) are consistent with the progressive dilution of a magmatic-hydrothermal component by local groundwaters.
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Foster, Pedro Luiz Luppi [UNESP]. "Geologia e petrologia do Maciço Palanqueta, Mina Bom Futuro, Rondônia." Universidade Estadual Paulista (UNESP), 2016. http://hdl.handle.net/11449/144675.
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Topázio granitos são rochas ácidas ultrafracionadas que ocorrem sob a forma de stocks, cúpolas ou diques em suítes graníticas pós-orogênicas ou anarogênicas, e são caracterizadas por seu enriquecimento extremo em flúor, associação com elementos litófilos e relação direta com muitos depósitos primários de metais raros (ex. Sn, W, Ta e Nb) encontrados pelo mundo. A mina Bom Futuro localiza-se no município de Ariquemes, região centro-norte de Rondônia, e é umas das maiores produtoras de estanho do país e congrega dois morros contíguos denominados Bom Futuro e Palanqueta, este último sendo o representante em superfície do Maciço Palanqueta. No Maciço Palanqueta são reconhecidas 5 fácies graníticas, sendo 4 delas topázio granitos: biotita-álcali-feldspato-granito equigranular, topázio-zinnwaldita-álcali-feldspato-granito equigranular, topázio-zinnwaldita-álcali-feldspato-granito porfirítico, topázio-zinnwaldita-álcali-feldspato-granito pórfiro e topázio-zinnwaldita-álcali-feldspato-granito miarolítico, além de diques de aplito, veios de pegmatito e veios e pipes de greisen mineralizados em cassiterita. Os veios pegmatíticos encontram-se cortando os diques de aplito e estes as demais fácies graníticas. As relações de contato entre as fácies graníticas é brusca, mas só é identificada relação de idade entre as fácies topázio-zinnwaldita-álcali-feldspato-granito porfirítico e topázio-zinnwaldita-álcali-feldspato-granito pórfiro. As características de campo, petrográficas e geoquímicas do Maciço Palanqueta permitem classifica-lo como um maciço granítico multifásico, intraplaca, tipo A e integrante peraluminoso da Suíte Granitos Últimos de Rondônia. Apesar de cronologicamente correlatos a seguinte ordem para a colocação das fácies graníticas é proposta: biotita-álcali-feldspato-granito equigranular topázio-zinnwaldita-álcali-feldspato-granito equigranular topázio-zinnwaldita-álcali-feldspato-granito porfirítico topázio-zinnwaldita-álcali-feldspato-granito miarolítico topázio-zinnwaldita-álcali-feldspato-granito pórfiro. O Maciço Palanqueta ainda não possui seus limites físicos definidos, bem como sua variação faciológica em seção, o que implica na possibilidade de potencial metalogenético em profundidade, em acordo com outros exemplos de topázio granitos encontrados na literatura.
Topaz granites are acidic ultrafracionated rocks that occur in the form of stocks, domes or dykes in granitic post-orogenic or anarogenic suites, and are characterized by their extreme enrichment in fluorine, association with lithophile elements and direct relationship with many primary deposits of rare metals (eg. Sn, W, Ta and Nb) found around the world. The Bom Futuro mine is located in the county of Ariquemes, north-central region of Rondonia State, and is one of the largest tin producer in the country and brings together two adjacent hills called Bom Futuro and Palanqueta, the last one being the representative surface of the Palanqueta massif. At the Palanqueta massif are recognized 5 granitic facies, 4 of them of topaz granites: equigranular biotite-alkali-feldspar granite, equigranular topaz-zinnwaldita-alkali-feldspar granite, porphyritic topaz-zinnwaldita-alkali-feldspar granite, porphyry topaz-zinnwaldita- alkali-feldspar granite and miarolitic topaz-zinnwaldita-alkali-feldspar granite, and aplite dikes, pegmatitic veins and veins and pipes of greisen mineralized in cassiterite. The pegmatite veins are cutting the aplite dykes and these all the other granitic facies. The contact relationships between the granitic facies is abrupt, but age relationship are only identified between the porphyritic topaz-zinnwaldita-alkali-feldspar granite and porphyry topaz-zinnwaldita-alkali-feldspar granite facies. The field, petrographic and geochemical data of Palanqueta massif allow classifies it as a within plate, A type, peraluminous. multifacies granitic massif, and member of the Younger Granites of Rondonia Suite. Although chronologically related the following order for placement of the granitic facies is proposed: biotite alkali-feldspar granite equigranular topaz-zinnwaldita-alkali-feldspar granite equigranular topaz-zinnwaldita-alkali-feldspar granite porphyry topaz-zinnwaldita -álcali-feldspar granite miarolítico topaz-zinnwaldita-alkali-feldspar granite porphyry. The Palanqueta massif does not have its physical boundaries defined, as well as their facies variation in vertical section, which implies the possibility of depth metallogenic potential, in accordance with other examples of topaz granites found in the literature.
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Dreyer, Tanya Shayna. "Petrogenesis of the peralkaline granite (and associated syenite) dykes of the Straumsvola Complex, Western Dronning Maud Land, Antarctica." Master's thesis, University of Cape Town, 2015. http://hdl.handle.net/11427/19964.
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The Straumsvola nepheline syenite complex in Western Dronning Maud Land, Antarctica consists of an outer massive and inner layered nepheline syenite that is itself intruded by ijolite. The complex and its immediate country rock was intruded by numerous dykes. A small proportion of these dykes are peralkaline syenite and microgranite, and these are found only to intrude the nepheline syenite and not the country rock. The presence of peralkaline granite dykes intruding a silica-undersaturated complex is unexpected, given the thermal divide that exists at low pressures between silica-under and -oversaturated phases. Major and trace element variations in the dykes are found to be consistent with fractional crystallisation of a parental peralkaline magma of trachyte composition.
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Wong, Lai-man Kennis. "Geochemistry of mafic dykes from the Discovery Bay granitic pluton, Hong Kong." Click to view the E-thesis via HKUTO, 2004. http://sunzi.lib.hku.hk/hkuto/record/B42577688.
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Oukemeni, Driss. "Géochimie, géochronologie (U-Pb) du pluton d'Aouli et comparaisons géochimiques avec d'autres granitoïdes hercyniens du Maroc par analyse discriminante /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1993. http://theses.uqac.ca.
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Stouraiti, Christina. "Geochemistry and petrogenesis of the Serifos Granite, in relation to other Aegean granitoids, Greece." Thesis, University of Leicester, 1995. http://hdl.handle.net/2381/34963.
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The young 9Ma Serifos pluton is the latest of a group of Miocene age medium- to high-K calc-alkaline granites, granodiorites and tonalites that were emplaced into the upper crust of the southern Aegean during back-arc extension. Serifos granitoid consists of a granodiorite, minor tonalite and abundant quartz-diorite enclaves. Most of these S. Aegean plutons have characteristics which vary between I-type and S-type, but their petrogenesis has been controversial. Here, different petrogenetic models are assessed using field criteria, major and trace element geochemistry, and Sr-Nd and O isotope systematics. The major element compositions of the Serifos granodiorie-tonalite and other I-type Cyclades granitoids are metaluminous to subaluminous, and have MgO, CaO, and TiO2 contents consistent with liquid compositions produced during amphibolite dehydration- melting experiments. Modelling of crystal fractionation processes using major elements would imply that removal of large amounts of plagioclase+hornblende +/- biotite is necessary to reproduce the Serifos evolved biotite-rich granodiorite from the quartz diorite magma; however, this is not consistent with the trace element variations. Conversely, mixing of the latter type of magma with a partial melt derived from the basement metasedimentary gneiss is consistent with both major- and trace-element trends, and new experimental data on melting of mixed amphibolite-sediment sources. The LILE elements particularly are controlled by the metasedimentary component. The Sr, Nd, and O isotope ratios of the Serifos and other Cyclades I-granitoids strongly indicate a crustal origin. Relationships between Rb/Sr, Sr, Nd, initial 87Sr/86Sr ratios, Nd/O isotope ratios are also consistent with binary mixing: magmas being derived from a mixed amphibolite/greywacke gneiss source available in the Cyclades basement, and with a significant metasedimentary contribution. Mixing of these two components in the source is a very important mechanism for explaining the distinct individual isotopic signatures of Serifos and the other Cyclades granitoids, but at the same time accounts for the continuous mixing trend (in terms of Sr, Nd, initial 87Sr/86Sr, Nd) seen for all I-type and S-type granites in the Cyclades, and indeed for most of the Eastern Mediterranean. The model could therefore be widely applicable. The geochemistry of the quartz diorite enclaves indicates some involvement of primary mantle-derived magma. Granite generation in the Aegean requires augmented thermal gradients, probably associated with lithospheric decompression from the early-Miocene to late-Miocene/Recent; this thermal perturbation may be a result of slab-breakoff. The increasing mantle heat input then accounts for the greater proportions of hornblende- dehydration melts incorporated in the progressively younger I-type granites (Naxos 12.5Ma, Mykonos 11.5Ma, Serifos 9Ma).
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Buick, Ian S. "The petrology and geochemistry of granitic rocks from the Entia domal structure, Harts Range, eastern Arunta Block, Central Australia /." Title page, contents and abstract only, 1985. http://web4.library.adelaide.edu.au/theses/09SM/09smb932.pdf.
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Sirbescu, Mona-Liza C. "Chemistry of magmatic fluids in the Harney Peak granite-pegmatite system, Black Hills, South Dakota /." free to MU campus, to others for purchase, 2002. http://wwwlib.umi.com/cr/mo/fullcit?p3060144.
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王冰媚 and Ping-mei Jean Wong. "Geochemistry, U-Pb and Sr-Nd-Hf isotopes of the Baijuhuajian A-type granites in Zhejiang Province: evidence for acontinuous extensional regime in the mid and late mesozoic." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2007. http://hub.hku.hk/bib/B39557297.
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Wong, Lai-man Kennis, and 王麗敏. "Geochemistry of mafic dykes from the Discovery Bay granitic pluton, Hong Kong." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2004. http://hub.hku.hk/bib/B42577688.
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Boudreaux, Andrew P. "Mineralogy and geochemistry of the Erongo Granite and interior quartz-tourmaline orbicules and NYF-type miarolitic pegmatites, Namibia." ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1854.
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The early Cretaceous anorogenic Erongo Granite of Namibia is known to host abundant boron mineralization in rounded, quartz-tourmaline clusters and in NYF-type miarolitic, pegmatitic cavities. Rock and mineral samples were taken from the bulk granite, tourmaline nests, and miarolitic cavities and analyzed using a variety of modern analytical techniques. Geochemical and mineralogical data suggest substantial input from the metasedimentary rocks of the Damara orogen was important in the genesis of the Erongo Granite magma. The geochemical signature of the Damara orogen is most evident in the tourmaline clusters and miarolitic cavities, where fractional crystallization accumulated volatile and incompatible elements enough to exsolve a second fluid phase and induce drastic textural and mineralogical changes. As a result, the geochemical character of the pegmatitic cavities is far removed from that of classic NYF-type systems, where boron mineralization is usually not observed.
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Bergström, Sara. "Fluid inclusions and geochemistry of the Peña del Seo W-deposit, northwest Spain : Controlling mechanisms for tungsten deposition." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-78194.
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The Peña del Seo tungsten deposit in northwestern Spain is situated in the tin (Sn)-tungsten (W) metallogenic province of Europe − one of the richest tin-tungsten (tantalum-lithium) mineral provinces in the world. The European Union’s current goal is to become self-sufficient of these commodities in the near future and the iTARG3T project was launched in order to improve the understanding and provide innovative exploration methods of these types of deposits. This master thesis will contribute to the iTARG3T project. The aim was to determine which physico-chemical conditions (temperature, pressure, salinity) that prevailed during the emplacement of the Peña del Seo deposit. A geochemical study was done consisting of a fluid inclusion study on the quartz veins from the deposit, and a whole-rock geochemistry analyse of the granitic rock. Homogenisation temperatures ranged between 97,6° C to 325,6° C and salinities (NaCl % equiv.) between 0,2% to 21,3%. The fluid was determined to consist of a two-component system of H2O and NaCl based on eutectic temperature. Based on its geochemical classification the granitic rock was considered to be an alkali granite, strongly peraluminous with S-type characteristics. At least two different types of fluids were present during the emplacement of the Peña del Seo deposit, one that was hot and with a moderate salinity, and one that had a lower temperature than the other fluid and a lower salinity, possibly meteoric water. The depositional mechanism of tungsten is thought to be caused by a combination between mixing between two fluids and cooling of the fluids, with the main depositional mechanism being cooling since the change in salinity was not of such magnitude that it would change the fluid chemical composition, while the decrease in temperature was. It is uncertain whether the granitic rock found at Peña del Seo is part of the granitic cupola of the greisen system. The granitic rock has similar characteristics as the leucogranites of the West Asturian-Leonese Zone and based on quartz vein morphology, which cut the D2 foliation, time of emplacement of the deposit could be linked to the syntectonic event at 320-310 Ma. If the relation between the granitic rock and the greisen system can be determined the time of emplacement would be possible.
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Johnson, Christopher M., and Daalen Christopher M. Van. "Mineralogy and geochemistry of Late Archean and Paleoproterozoic granites and pegmatites in the Northern Penokean terrane of Marquette and Dickinson Counties, Michigan." ScholarWorks@UNO, 2015. http://scholarworks.uno.edu/td/2088.
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This thesis focuses on mineralogy, geochemistry, and origin of eight pegmatites and two spatially associated granites of Late Archean and Paleoproterozoic ages located in Marquette and Dickinson Counties, Michigan. Biotite geochemistry reveals that both granites and all pegmatites are peraluminous and have an orogenic signature. However, bulk composition reveals the Humboldt granite is a peraluminous A-type granite and the Bell Creek granite is a peraluminous mix between I-, S-, and A-type granites. The Republic Mine pegmatite appears to be geochemically similar to the Bell Creek granite and Grizzly pegmatite. The Crockley pegmatite is genetically related to the Humboldt granite. The Groveland Mine, Sturgeon River, and Hwy69 pegmatites appear to be a product of the Peavy Pond Complex being contaminated with the Marquette Range Super Group. Contamination and anatexis have made classification of the granites and pegmatites problematic. The Grizzly should be classified as a primitive LCT-type even though this pegmatite lacks characteristic enrichment associated with LCT pegmatites. Mineralogical geochemistry reveals that the Republic Mine is relatively more primitive than other pegmatites and should be classified as a primitive Mixed-type pegmatite. Groveland Mine has mineralogy and geochemistry not normally associated with NYF-type pegmatites and should be classified as Mixed. The Crockley pegmatite should be classified as NYF-type with a primitive LCT overprint. Dolfin, Hwy69, Sturgeon River, and Black River pegmatites should be classified as Rare Element, REE, NYF-type, although the Black River has slight tantalum enrichment expressed in columbite group minerals.
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Adriaans, Luke. "Geology, geochemistry and Sr-Nd isotope analysis of the Vredenburg Batholith and Cape Columbine Granites Paternoster/Vredenburg, South Africa: Implications on their petrogenesis, tectonic setting, and sources." University of the Western Cape, 2018. http://hdl.handle.net/11394/6527.
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>Magister Scientiae - MScThe late− to post−collisional Cape Granite Suite (CGS) located in the southwest of South Africa is comprised of S−, I−, and A−type granites, mafic intrusives, and volcanic flows. The CGS is interpreted to have formed during the closing of the Adamastor Ocean during the Late−Proterozoic to Early−Cambrian. Recently, the S−type granites have received much attention concerning their petrogenesis and sources. However, the I− and A−type granites remain poorly understood and little studied. Therefore, with new geochemical and isotopic data the petrogenesis, sources, and tectonic settings of I− (Vredenburg Batholith) and A−type (Cape Columbine) granites of the CGS form the focus for this study. The major and trace element data presented in this thesis show that the granites from the Vredenburg Batholith are weakly peraluminous to metaluminous, ferroan, and alkali−calcic. Associated with the granites are metaluminous, magnesian, and calc−alkalic igneous enclaves. Formerly, the granites have been interpreted to have formed by fractionation. However, with new geochemical analyses and reassessment of such models, it can be shown that such processes are incompatible with accounting for the chemical variation displayed by the granites and their enclaves. Moreover, the I−type granites and enclaves exhibit positive linear trends between whole−rock major and trace elements vs. maficity (Fe + Mg), which can be explained by co−entrainment of peritectic and accessory phases. The lithogeochemical characteristics of the enclaves and host granite reflect melting of a heterogeneous source. Moreover, the granite and enclave's εNd(t) values reflect melting of Paleoproterozoic-aged crustal sources. Finally, with tectonomagmatic discrimination diagrams, it can be shown that the tectonic setting of the granites indicates a transition from a collisional to extensional regime which corroborates the inferences of previous studies. The Cape Columbine Granites lithogeochemical characteristics are ferroan, calc−alkalic and weakly peraluminous. They show typical A−type granite characteristics in having high silica content, high Na + K values, REE enrichment as compared to S− and I−type granites and strong negative Eu anomalies. For this thesis, it can be shown that anatexis of quartzofeldspathic protolith in an extensional regime produced the chemical variation of the Cape Columbine Granite. Moreover, their isotope ratios are typically radiogenic, indicative of a crustal origin. With this new geochemical data evidence is provided against and in support of previous inferences made about the petrogenesis of the I− and A−type granites of the CGS. This also betters our understanding of the magmatic processes involved in the construction of the CGS over time.
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Stremtan, Ciprian Cosmin. "Mantle-crust Interaction in Granite Petrogenesis in Post-collisional Settings: Insights from the Danubian Variscan Plutons of the Romanian Southern Carpathians." Scholar Commons, 2014. https://scholarcommons.usf.edu/etd/5624.
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The issue of granite petrogenesis plays a key role in our overall understanding of the growth and differentiation of continents, as well as in our ability to unravel the tectonic histories of orogenic belts. Granites are ubiquitous magmatic products found in almost all tectonic settings: oceanic and continental rifts (i.e., plagiogranites - extreme basalt differentiates), active continental margins (e.g,. the granitic batholiths of central and southern Andes), continent-continent collision zones (e.g., the orogenic batholiths of the Himalayas, Western Anatolia), post-collisional settings (e.g., the Variscan provinces of Europe), complex within-plates settings (e.g., Limmo massif, Afar, Ethiopia). Furthermore, granitoids are characterized by considerable petrological and geochemical heterogeneity, as they can form from a vast array of sources: sediments (e.g., pelites, arkoses, psammites), metamorphic rocks (e.g., (mica)schists, gneisses, etc.), and igneous rocks (e.g. andesites, dacites, tonalites, etc.). Aside from fertile sources (i.e., protoliths), granite petrogenesis is dependent upon two critical parameters: temperature (to promote melting of the protoliths) and water availability - either as freely available aqueous solutions/vapors (e.g., water input in subduction zones); or water released via dehydration melting of hydrous minerals (e.g., micas, amphiboles). The presence of water in protoliths depresses the melting temperature of mineral components and provides the environment for redistribution of chemical components.
Understanding the origins of granitic rocks presents unique challenges, given that in many of the tectonic settings where granites are encountered, it is clear that their modes of formation can involve a spectrum of igneous and metamorphic processes that are not readily accessible for examination, either through the study of modern environments or via analogy to "classical" localities. The petrogenesis and emplacement of granites in post-collisional tectonic settings is one of the thornier challenges, as these rocks appear to be derived via thermal and magmatic processes within highly deformed and compositionally diverse continental crust for which we lack a clear understanding. A number of unconventional and difficult-to-test mechanisms have been posited to drive crustal heating, melting, and subsequent pluton post-collisional emplacement. Although large volumes of granitic magmas have been emplaced in post-collisional settings, the complexities of the processes active in such settings make it challenging to put forward testable models that effectively combine available geochemical, petrologic, and geophysical data. Models for granite genesis away from plate margins (by means of crustal thickening, thermal blanketing, and internal heating from radioactive decay of 40K, 230Th, 235U, and 238U; delamination of the crustal lithosphere and juxtaposition of hot mantle melts at the base of the crust; underplating of mantle melts; or slab brake-off and upwelling of mantle melts) have been successfully applied in comparatively young orogenic regions, such as the Himalayas, the Carpathians, and Turkey. These models have proven challenging to employ in older orogenic belts, given their sometimes intricate tectonic and metamorphic histories, and the loss of pertinent evidence due to the effects of post-emplacement tectonic reworking, and often extensive alteration and erosion.
A series of ancient but fresh, age-correlative granitic plutons are exposed in Alpine nappes on the flanks of the Carpathians Mountains in southwestern Romania. These granites, all mapped as intruding the Neoproterozoic basement of the Danubian tectonic terrane, were emplaced during the post-collisional stages of two world-scale orogenies: an older, Pan-African event (~600 Ma) and a younger, Variscan event (~330- 280 Ma). My dissertation is focused on the study of late Variscan post-collisional plutons and associated sub-volcanic dykes, as they are tremendous tools for understanding and quantifying the mantle-crust interaction in post-collisional environments and the overall evolution of the continental crust during the Variscan orogeny.
Originally believed to be Proterozoic in age, zircon U/Pb dating showed that the plutons are much younger (Chapter 1 - Post-collisional Late Variscan magmatism in the Danubian domain (South Carpathians, Romania) documented by zircon U/Pb LA-ICP-MS) and correspond to the latest stages of the Variscan orogeny, as recorded elsewhere in the European Variscan provinces. The granitic plutons are relatively small and are generally concordant with the structures preserved by the country rocks. The extraordinary petrological and geochemical heterogeneities, even at pluton scale (Chapter 2 - Petrology and geochemistry of the Late Variscan post-collisional Furătura granitic pluton South. Carpathian Mts. (Romania)) argue against unique protoliths and simple evolutionary processes (e.g., closed-system fractional crystallization; anatexis). Trace elemental data for the Furătura pluton shows that the melts were formed in equilibrium with a garnet-amphibole restite, under pressure-temperature conditions deeper than the plagioclase stability field, implying that the melting took place at depths in excess of 40 km in the continental crust. Stable and radiogenic isotope data suggest that a protolith was of (possibly enriched) mantle affinities, and that the melts were subsequently contaminated in various degrees by deep crustal lithologies. In comparison, other post-collisional Variscan plutons from the Danubian domain (Chapter 4 - The role of the continental crust and lithospheric mantle in Variscan post-collisional magmatism - insights from Muntele Mic, Ogradena, Cherbelezu, Sfârdinu, and Culmea Cernei plutons (Romanian Southern Carpathians)) have trace elemental compositions that suggest they were formed at different levels in the crust, under P-T conditions corresponding to both garnet-amphibole and plagioclase stability fields. Some of the plutons lack mantle geochemical signatures and their isotopic compositions are indicative of substantial involvement of both lower- and upper-crustal rocks in their formation and subsequent evolution. On the other hand, plutons emplaced during the same time interval and most likely in close geographical proximity have trace elemental and isotopic compositions indicating strong input from previously enriched mantle components which experienced various degrees of assimilation fractionation-crystallization and/or assimilation of continental crust material during their evolution. This variability in both protoliths and processes responsible for the formation of the granites, coupled with the presence of mantle signatures in late-orogenic post-collisional melts are strong evidence to support delamination as means of providing both the mantle-derived input and energy required for generation of granitoids in the crust. The pronounced variation in petrological and chemical compositions of synchronous plutons suggests that delamination in the Danubian domain was not a single, large scale event that affected the entire crust, but rather a collection of disparate, spatially and chronologically limited event, that affected the Variscan crust during the latest stages of the orogeny.
This hypothesis is further tested on a series of sub-volcanic dykes (the Motru Dyke Swarm) crosscutting the entire Danubian basement (Chapter 3 - Post-collisional magmatism associated with Variscan orogeny in the Danubian Domain (Romanian Southern Carpathians): the Motru Dyke Swarm). Initially, the emplacement age of these dykes was assumed as "pre-Silurian" but our mapping has showed that they intrude components of the Danubian domain that shared a documented common history not earlier than the Carboniferous. Furthermore, the dykes are in intrusive relationship with two of the Danubian Variscan plutons, thus arguing for an early Permian emplacement age. Geochemical data show extraordinary heterogeneities in the dykes' composition and record both mantle and crust involvement in their formation. The dykes were emplaced at much shallower depths in the crust, as compared with the granitic plutons. Still, their isotopic compositions clearly indicate that they sampled both lower- and upper-crustal compositions during their evolution. This means that after the crustal thickening episodes that define continent-continent collisions, during the latest stages of the Variscan orogeny, the crust became progressively thinner, as a way to compensate for its metastable state. Thinning of the crust is greatly favored by delamination of the lithosphere. A delamination event, which usually postdates the cessation of continental collision or prolonged crustal shortening, involves the geologically rapid foundering of negatively buoyant lithosphere comprised of mantle and (potentially) lower crust into underlying hotter and less dense asthenosphere. Such a process will remove the lithospheric mantle (and potentially segments of the lower crust) along pre-existing lineaments or mechanical flaws, and juxtapose hot upwelling asthenosphere against the base of the crust, leading to partial melting.
Field, petrological, and geochemical data presented in my dissertation document pronounced variations in the overall composition of synchronous plutons and dykes, and further suggest that delamination in the Danubian domain was an active process. This bears great importance in our understanding of the evolution of the crust and argues that mantle-crust interactions are responsible for the generation of continental crust even in the latest stages of an orogen.
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Nethenzheni, Sedzani Shane. "The geochemistry, geochronology and petrogenetic characteristics of two granitic suites on the eastern margin of the Namaqua Sector, Namaqua-Natal Mobile Belt, South Africa." Thesis, University of the Western Cape, 2016. http://hdl.handle.net/11394/5209.
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>Magister Scientiae - MScThe group of granites on the eastern margin of the Mesoproterozoic Namaqua sector of the polydeformed and highly metamorphosed Namaqua-Natal Province of southern Africa is known as the Keimoes Suite. The suite includes mixtures of diverse rock types not belonging to a single intrusive series and so it should be subdivided into more than one intrusive suite. The exact definition, extent, distribution and petrogenesis of these granites have been poorly defined in the past, with various authors defining the suite differently due to the lack of proper geochronology and geochemical data. The exact contact between the Namaqua sector and Kaapvaal Craton together with the role of the suite to the Namaqua tectonic evolution is still unclear. The granites of the Keimoes Suite are thought to mark the contact between the Namaqua sector and the Kaapvaal Craton. This study seeks to address the above mentioned problems by making use of new geochronology, isotope, major and trace element geochemistry together with petrography. The granites of the Keimoes Suite were previously grouped based on their degree of deformation. The geochronology, undertaken as part of this study, has proven that this classification is unfounded. The degree of foliation in these granites appears to be largely controlled by the abundance of platy minerals, such as biotite and muscovite, together with the intrusion mechanism, with deformational processes, such as shearing, playing a secondary role. The geochronology, together with geochemistry has helped to redefine the previously defined Keimoes Suite so that two well defined separate suites are recognized and the third is poorly defined due to lack of more samples of that age group. The new classification or grouping of the granites of the eastern Namaqua sector allows a more detailed examination of the tectonic evolution of this region. A member of the 1225 to 1200 Ma early syn-tectonic granites, the Josling Granite, shows a strongly developed foliation and was derived from a depleted source with a relatively low continental crustal component. This granite intruded during the time of arc accretion, and is associated with, and partly responsible for the D₁ deformation and M₁ metamorphism recognized in most of the rocks of the eastern terranes of the Namaqua sector. In terms of age, the syn-tectonic granites of the Augrabies Suite extend from 1200 to 1120 Ma and were largely derived from depleted sources with variable but more substantial amounts of continental crustal components as compared to the early syn-tectonic granite. The granites of this suite intruded during the period of peak D₂ deformation with peak magmatism between 1180 - 1135 Ma, and particularly around 1150 Ma, during the peak of metamorphism (M₂) caused by, and associated with these voluminous intrusions. The Keimoes Suite can now be defined as comprising granites of late- to post-tectonic age relative to the 1.2 - 1.08 Ga Namaquan Orogeny with magmatism occurring on the western side of the Kaapvaal Craton. The 1116 to 1066 Ma Keimoes Suite intruded during the stage of the Namaquan Orogeny in which there was continued indentation of the Kaapvaal Craton into the Namaqua sector with wrenching and shearing causing the development of rifting into which the granites intruded. The Keimoes Suite granites were derived from continental crustal sources and incorporated varying degrees of depleted source components. The intrusives and extrusives of this age occured after the main collisional event between the Namaqua Sector and the Kaapvaal Craton and are associated with the D₃ deformational event, imparting the thermal conditions leading to the M₃ metamorphic event of the rocks within both the Kakamas and Areachap Terranes. The suites mark the suture between the Archean Kaapvaal Craton and the Proterozoic Namaqua sector. The compositions of the granites of the individual suites were mainly controlled by the source with the degree of partial melting exerting a major control. The proportion of entrained peritectic assemblages and accessory minerals played a major role in controlling the compositions of the granites, particularly those of the trace elements. Variations within the compositions of the same suite are due to source heterogeneities. Generally, fractionation processes played a secondary role in influencing the composition of the granites.
Council for Geoscience and National Research Foundation
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Alves, Marlon Andrek da Silva. "Alteração intempérica do depósito de Sn-Nb-Ta-(criolita, ETR, U, Th) madeira, Mina Pitinga (AM)." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/148921.
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A dissertação versa sobre a lateritização do depósito Madeira que ocorre associado à fácies albita granito do granito Madeira (tipo A, ~ 1,82 Ga). O depósito Madeira situa-se na floresta amazônica, onde intemperismo químico é intenso e lateritização é um importante processo de formação de depósitos minerais. Este depósito representa um caso particular, onde a rocha-mãe é um depósito mineral; assim, mineralização primária e mineralização laterítica ocorrem no mesmo perfil. A rocha-mãe tem uma associação mineral incomum, que inclui quartzo, albita, k-feldspato, zircão, criolita (Na3AlF6), fluorita, polilitionite, riebeckita rica em Zn, F-anita rica em Zn, torita, cassiterita, pirocloro, columbita, xenotima, gagarinita- (Y), fluocerita-(Ce) e genthelvite. Uma característica importante da rocha é a sua riqueza em flúor (2 a 6% em peso), principalmente sob a forma de criolita ou fluroita na matriz. Inicialmente foram investigadas as alterações micromorfológicas destes minerais ao longo de perfis de intemperismo. Em seguida, os realizados estudos geoquímicos em perfis selecionados. Os dados químicos foram convertidos em proporções volumétricas para quantificar as variações nos teores de elementos em amostras com diferentes graus de lateritização, e foram realizados cálculos de balanço de massa tendo o Al como elemento de referência. Desta forma, foram obtidas muitas informações sobre os processos que atuaram na formação do perfil laterítico a partir do depósito Madeira. A rocha-mãe representava claramente um sistema aluminoso com quantidades mais baixas de Fe. A perda total de álcalis e perda parcial de SiO2 originou argilas cauliníticas. A razão molar de SiO2/Al2O3~2 foi adequada para a geração de minerais de argila aluminosos com estrutura 1:1, tais como a caulinita. Com a maior perda de SiO2 na parte superior do perfil ocorreu a formação de gibsita. Hematita é principal mineral de ferro formado porque o meio foi alcalino com alta razão OH/Fe (>2). A lixiviação de elementos alcalinos conduziu ao enriquecimento relativo de alguns elementos economicamente importantes, tais como Sn, Nb e ETR. No entanto, a distribuição de alguns metais, tais como o Pb, Zn e ETR, difere do padrão normalmente esperado no intemperismo, o que pode ser explicado por algumas características especiais da paragênese e pela alta atividade de F nas soluções, que influenciou os processos intempéricos de duas maneiras diferentes: intensa corrosão até mesmo de minerais muito resistentes e formação de complexos estáveis, especialmente com cátions duros, tais como os ETR.The paper deals on the laterization of the Madeira deposit associated with the albite-enriched granite facies of the A-type Madeira granite (~1.82 Ga). The Madeira deposit is located in the Amazon rain forest, where chemical weathering is intensive and lateritization is a major process of ore deposit formation. This deposit represents a particular case, where the parent rock is an ore deposit; thus primary mineralization and lateritic mineralization occur in the same profile. The parent rock has an unusual mineral association, which includes quartz, albite, k-feldspar, zircon, cryolite (Na3AlF6), fluorite, polylithionite, Zn-rich riebeckite, Zn-F-rich annite, thorite, cassiterite, pyrochlore, columbite, xenotime, gagarinite-(Y), fluocerite-(Ce), and genthelvite. An important feature of the rock is the F richness (2 to 6% wt) mainly in the form of cryolite or fluorspar in the matrix. We first investigated the micromorphological changes of these minerals throughout the soil profile and then focused the geochemical studies in selected profiles. The chemical data were converted into volumetric proportions to quantify the variations in element contents in samples with different degrees of lateritization, and we performed mass balance calculations with Al as the reference element. In this way, we obtain many new constraints on the processes that formed the weathering profile from the Madeira deposit. The parental rock was a clearly aluminous system with lower amounts of Fe. The total loss of alkalis and partial loss of SiO2 created kaolinitic clay minerals. The SiO2/Al2O3 molar ratio ≈2 was suitable for generating aluminous clay minerals with 1:1 structures, such as kaolinite. Greater losses of SiO2 occurred and gibbsite formed at the top of the weathering profiles. Hematite formed as the main ferric mineral because the medium was alkaline with a high OH-/Fe ratio (> 2). The leaching of alkaline elements led to relative enrichment in some economically important elements, such as Sn, Nb, and REEs, in the lateritic profiles. However, the distribution of some of the metals, such as Pb, Zn, and REEs, in the weathering profile is very unusual and may be explained by some special characteristics of the paragenesis and the high activity of F in the solutions, which greatly influenced the weathering processes in two different ways. This halogen was responsible for the intense corrosion of even very resistent minerals and formed stable complexes, especially with hard cations such as REEs.
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English, Luke D. "A discussion of the 3D geometry, ascent and emplacement mechanisms for the Anabama granite, South Australia using TMI data, geochemistry and core logs /." Adelaide, 2002. http://web4.library.adelaide.edu.au/theses/09SB/09sbe578.pdf.
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Matos, Strauss Javier Fabian. "An εHf and δ18O Isotopic Study of Zircon of the Mount Osceola and Conway Granites, White Mountain Batholith, New Hampshire: Deciphering the Petrogenesis of A-Type Granites." BYU ScholarsArchive, 2021. https://scholarsarchive.byu.edu/etd/9189.
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A-type granites form in anorogenic settings and typically have high REE concentrations, K2O, Na2O, SiO2, FeOtotal, but low contents of Al2O3, MgO, CaO compared to other granite types. They have been divided in two groups according to their geochemical characteristics: differentiates of mantle-derived magmas (A1), and granites that are the result of melting depleted, lower crust (A2). The two largest A-type granites of the Mesozoic White Mountain Batholith of New Hampshire are the Mount Osceola and Conway granites. Electron microprobe analyses of biotite and amphibole in both granites are similar to those in other A-type granites: Fe-rich, but low MgO, and Al2O3. Whole-rock major and trace elements compositions of the Mount Osceola and the Conway granites are similar; both have high contents of REE, Zr, Nb, high Nb/Y ratios, and low CaO, Eu, and Sr and other compatible elements. Based on their high Nb/Y ratios, both granites are classified as mantle-derived magmas (A1). Microanalyses of ẟ18O and ƐHf of zircon show significant crustal contamination in both granites. The ẟ18O values for zircons from the Mount Osceola are between 7.4-8.9‰, and for the Conway Granite are 7.0-8.1‰. These values are distinct from mantle zircon (ẟ18O 5.3±0.3‰), which indicates large degrees of crustal contamination in both granites. Additionally, ƐHf (188Ma) for the Mount Osceola zircon ranges from -1.1 to +3.4, and those from the Conway Granite range from -2.1 to +4.6, indicating magma derivation in depleted mantle (ƐHf > 0) along with a crustal component. Although both granites have A1 compositions suggesting a mantle-derivation, this simple process is not recorded by the zircons. These zircons crystallized after considerable crustal contamination of mantle-derived A1 magmas and missed capturing the signature of that mantle component.
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Henze, Porter. "Implications of Geochemistry and Textures of Titanite for the Geologic Histories of the Notch Peak Intrusion and Little Cottonwood Stock, Utah." BYU ScholarsArchive, 2020. https://scholarsarchive.byu.edu/etd/8607.
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Textural and compositional variations in titanite, along with whole-rock geochemistry, provide constraints on the emplacement and cooling histories of two plutons: the Jurassic Notch Peak pluton and the Oligocene Little Cottonwood stock, both in Utah. Titanite textures observed with back-scattered electron (BSE) imaging along with their compositions were used to determine four periods of growth: cores, rims, interstitial overgrowths, and secondary replacements. Brightness in BSE images correlates mostly with rare earth elements (REE). REE patterns in cores and rims are compositionally similar in both plutons, although the Notch Peak intrusion tend to be slightly more enriched in REE. Overgrowths and secondary replacements typically have lower concentrations of REE and Fe and higher Al, Mn, F, and U. They also have similar δ18O values to primary titanite, indicating alteration and recrystallization from exolved magmatic fluids rather than meteoric sources. In the Notch Peak intrusion, titanite grains usually have simple, oscillatory zoned textures that include cores which include bright sector zones. These are overprinted by secondary titanite that grows within and replaces the primary titanite grain. At some localities, Notch Peak titanites have been hydrothermally altered to fine-grained aggregates of rutile or brookite, magnetite, quartz, and plagioclase. These observations indicate a simple cooling path after magmatic intrusion, followed by hydrothermal alteration for the Notch Peak intrusion. The Little Cottonwood stock contains titanite grains that are distinctly different from those in the Notch Peak intrusion. They typically contain a distinct patchy core with rounded, resorbed ilmenite inclusions. Surrounding the core is a mantle of oscillatory zoned titanite. On many grains, narrow rims of secondary overgrowths are observed as well as interstitial titanite growing in between chloritized biotite sheets. The cores of these titanite grains suggest that a more reduced, ilmenite-rich magma mixed into an oxidized felsic magma, destabilizing existing ilmenites and forming its patchy texture. This was followed by hydrothermal overgrowths and interstitial titanite, like Notch Peak, but to a lesser extent. Although both plutons had similar emplacement settings–subduction related intrusion into Paleozoic limestone–their whole rock and titanite chemistries are different. The Notch Peak intrusion is more chemically evolved and less mafic than the Little Cottonwood stock. The patchy cores with Fe-Ti oxide inclusions found in the Little Cottonwood stock, along with the abundance of mafic enclaves in the pluton, provide evidence for magma mixing, while no evidence is observed in the Notch Peak intrusion for magma mixing.
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Lambert, Christopher William. "Granitic melt transport and emplacement along transcurrent shear zones : case study of the Pofadder Shear Zone in South Africa and Namibia." Thesis, Stellenbosch : Stellenbosch University, 2013. http://hdl.handle.net/10019.1/85682.
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Thesis (MSc)--Stellenbosch University, 2013.ENGLISH ABSTRACT: The close spatial and temporal relationship of shear-zones and magmas is commonly interpreted to indicate positive feedback between magma migration, granitic emplacement and shear-zone-associated deformation. Emplacement geometries and structural fabrics are however rarely preserved, hampering the study of shear-zones and granitic magmas interactions. This study focuses on an area around the Pofadder Shear Zone (PSZ) in Namibia and South Africa as a case study for granitic bodies, mainly as pegmatite sills and dykes, and their spatial and temporal relationships to a crustal-scale shear-zone. The PSZ is a NW-SE trending, dextral, Mesoproterozoic-Neoproterozoic transpressional shear-zone in Namaqualand, interpreted to have accommodated late-stage lateral escape of the Namaqua Metamorphic Complex in response to southward indentation of the Kaapvaal Craton around 1030 – 1080 Ma. In this study it is shown that the shear-core records an asymmetrical strain variation across the PSZ. This is indicated by pervasively banded ultramylonites, mylonites and the significant development of pervasive phyllonites at the southern margin, defining the internal ductile to brittle-ductile fabrics of the shear, during a progressive deformational evolution. Mapping of the PSZ fabrics and associated pegmatites documents how pegmatites are emplaced in structurally distinctive sites within, and adjacent to the PSZ. New U-Pb monazite ages derived from this study, show how pegmatite emplacement has occurred at different times of shear-zone development. The pegmatites are emplaced into earlier ductile to later brittle-retrograde fabrics that accompanied the ca. 45 Ma shear-zone exhumation. Pegmatites concentrated along the northern PSZ-margin are interpreted to be controlled by anisotropies developed axial planar to large km-scale and parasitic folds during the initial, predominately strike-slip stages of shearzone deformation that occurred as early as 1005 ± 5 Ma. Within the PSZ core, pegmatite emplacement is controlled by the syn-kinematic development of (a) subvertical, mylonitic and phyllonitic foliations and (b) fracture permeabilities created by synthetic Riedel shears and dextral dilatant jogs. The most significant pegmatite development around the PSZ is the Skimmelberg Pegmatite Stockwork (SPS) which forms an extensive interconnecting network of concurrent, foliation-parallel sills and thick (> 50 m) discordant dykes within the southern footwall of the PSZ. The dykes intrude as late as 958 ± 5 Ma into feather-shaped N-S extensional fractures (mode I) that developed due to episodic stick-slip at the boundary between the PSZ core and footwall rocks during periods of late-stage transpression. The SPS forms a steeply dipping fracture network that not only creates space needed for emplacement but effectively acts as a conduit for magma transport along the margin of the PSZ. The large extensional fractures of SPS create the necessary hydraulic gradients to tap the magma source of a regional trending pegmatite belt and form a sheeted complex adjacent to the PSZ. Therefore, this study documents how, during the progressive exhumation of a largescale transcurrent shear-zone, magma emplacement is not only concentrated within the highly permeable, high-strain domains (cores) of shear-zones but may be concentrated in diachronous, structurally controlled sites along the shear-zone margins.
AFRIKAANSE OPSOMMING: Die noue ruimte-tydsverband tussen skuifskeure en magmas word algemeen geïnterpreteer as ‘n aanduiding van positiewe terugkoppeling tussen magma migrasie, graniet-inplasing en skuifskeurgeassosieerde vervorming. Geometrie en struktuurmaaksels van inplasings word egter selde bewaar en belemmer die studie van interaksies tussen skuifskeure en graniet-magmas. Die studie fokus op ‘n area rondom die Pofadder Skuifskeur (PSS) in Namibië en Suid-Afrika as ‘n gevallestudie vir graniet-liggame, hoofsaaklik as pegmatiet plate en gange, asook voorafgenoemde se ruimte-tydsverband met ‘n grootskaalse skuifskeur. Die PSS is ‘n NW-SO-waarts strekkende, regs-laterale, Mesoproterosoïse-Neoproterosoïse transpressieskuifskeur in Namakwaland, wat geïnterpreteer word om die latere-stadium laterale ontsnapping van die Namakwa Metamorfiese Kompleks te akkomodeer in reaksie op die suidwaartse indrukking van die Kaapvaal Kraton omstreeks 1030-1080 Ma. In hierdie studie word getoon dat asimmetriese vervormingsvariasie deur die skuifskeurkern aangeteken word. Hierdie word aangetoon deur gebande ultramilioniete, milioniete en die noemenswaardige ontwikkeling van filoniete wat die suidelike rand deurtrek en definiëer die interne plastiese- tot bros-plastiese maaksels van die skuifskeur gedurende ‘n progressiewe vervormingsevolusie. Kartering van die PSS maaksels en geassosieerde pegmatiete dokumenteer hoe pegmatiete, aangrensend en binne die PSS, in eiesoortige strukturele terreine binnedring. Nuwe U-Pb monasiet ouderdomme, afgelei vanuit hierdie studie, toon aan hoe inplasing plaasgevind het gedurende verskillende tye van skuifskeurontwikkeling. Pegmatiete het vroeëre plastiesetot latere bros-retrogressiewe maaksels binnegedring wat die herontbloting van die ca. 45 Ma skuifskeur meegaan. Pegmatiete, gekonsentreerd langs die noordelike rand van die PSS, word geïnterpreteer as beheer deur anisotrope wat parallel aan die asvlak van groot km-skaalse en ondergeskikte plooie ontwikkel gedurende die aanvanklike, hoofsaaklik strekkingwaarste, stadiums van skuifskeurontwikkeling wat so vroeg as 1005 ±5 Ma plaasgevind het. Binne die kern van die PSS word die inplasing van pegmatiete beheer deur die sinkenimatiese ontwikkeling van (a) subvertikale, milionitiese- en filonitiese foliasies en (b) breukdeurdringbaarheid wat gevorm is deur sintetiese riedelskuifskeure en regslaterale uitsettende “jogs”. Die mees noemenswaardige pegmatiet ontwikkeling rondom die PSS is die Skimmelberg Pegmatiet Stokwerk (SPS) wat ‘n intensiewe netwerk vorm van intergekonnekteerde konkurrente plate, parallel aan die foliasie, en dik (>50m) diskordante gange binne die suidelike vloer van die PSS. Die gange dring in so laat as 958 ± 5 Ma binne-in veervormige N-S uitbreidende breuke (modus1) wat ontwikkel het as gevolg van die episodiese hak-en-glip op die grens tussen die PSS kern- en vloergesteentes gedurende periodes van laat-stadium transpressie. Die SPS vorm ‘n styl hellende breuk-netwerk wat nie net spasie maak vir indringing nie, maar dien ook effektief as ‘n geleidingsweg vir die vervoer van magma langs die rand van die PSS. Die groot uitbreidende breuke van die SPS skep die nodige hidroliese gradiënt om die magma bron van ‘n regionale pegmatiet gordel te tap en vorm ‘n bladvormige kompleks aangrensend tot die PSS. Gevolglik dokumenteer die studie hoe, gedurende die progressiewe ontbloting van ‘n grootskaalse torsieskuifskeur, magma inplasing nie net gekonsentreer is binne die hoogs deurdringbare, hoogsvervormde areas (kerne) van skuifskeure nie, maar ook hoe magma kan konsentreer in diachroniese, struktuur beheerde gebiede teen die rande van skuifskeure.
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Vedana, Luiz Alberto. "Balanço geoquímico de massa entre as fácies do Granito Madeira - Pitinga (AM) Luiz Alberto Vedana." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2010. http://hdl.handle.net/10183/27037.
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A mina Pitinga é a maior produtora de Sn do Brasil, possuindo um depósito de classe mundial com 164 milhões de toneladas de minério disseminado, com 0,17% de Sn; Nb e Ta são explorados como subprodutos. Criolita, Y, ETR, Zr, Rb, Th, Li e U são potenciais subprodutos do minério disseminado. Na parte central da jazida ocorre o depósito criolítico maciço (DCM) com 10 milhões de toneladas de minério (32% de Na3AlF6). O granito Madeira é um corpo zonado constituído por quatro fácies: anfibóliobiotita sienogranito porfirítico (GR), que possui textura rapakivi; biotita-feldspato alcalino granito (BG); feldspato alcalino granito hipersolvus (GH) e albita granito. O albita granito é subdividido na subfácies de núcleo (AGN) e na subfácies de borda (AGB). Os trabalhos anteriores sobre a origem e evolução do granito e das mineralizações deixaram em aberto as seguintes questões: (i) as quatro fácies derivariam de um mesmo magma ou as fácies precoces (GR e BG) seriam oriundas de um magma diferente daquele que gerou as fácies mais tardias (AGB/AGN e GH); (ii) a origem do AGB deve-se ao autometassomatismo do AGN ou outros processos intervieram? (iii) é viável a hipótese de que o DCM ocupe espaços gerados pela corrosão de minerais primários do albita granito, como supõe o modelo genético hidrotermal? Na tentativa de elucidar estas questões, foi realizado um balanço geoquímico de massa para quantificar as perdas e ganhos relativos entre os pares de fácies e subfácies analisados. Os resultados indicam que os maiores teores de Si, Na, F e Li das fácies tardias, assim como as diferenças de comportamento dos ETR, reforçam a idéia de que as fácies precoces (GR e BG) tiveram origem em um magma distinto daquele que formou as fácies posteriores (albita granito e GH). A homogeneidade química do AGB, em conjunto com a menor concentração de Na, F, H2O, ETRL, assim como as concentrações de minerais de minério e subprodutos, sugerem uma ascensão e cristalização desta subfácies como sendo anterior ao AGN. Por isso as paragêneses primárias destas subfácies são diferentes. A comparação do AGN com o DCM, utilizando o cálculo do balanço geoquímico de massa, possibilitou verificar uma expressiva diferença de volume indicando que, para a formação do depósito criolítico maciço, foi necessária a corrosão e consumo de AGN.Pitinga is the largest producer of Sn in Brazil having a world-class deposit, with 164 million tones of ore with 0.17% Sn, and contain Nb, Ta and cryolite ores. In the granite core have a massive cryolite deposit (MCD) (32% of Na3AlF6) with 10 million tons of ore. Other elements as Y, REE, Zr, Rb, Th, Li and U are exploitable as by-products. The Madeira granite is constituted by four fácies: amphibole-biotite sienogranite; (GR.), that have rapakivi texture; biotite-alkali feldspar granite (BG); hypersolvus alkali feldspar porphyritic granite (GH), and albite granite. The albite granite is divided in two subfácies: core (AGN) and border (AGB). The AGB was interpreted in previous papers as possible generated by autometasomatism of the core subfacies. Some models of the origin and evolution of Madeira granite and its mineralization have been proposed previously, and permit the following discussions: (i) all facies of Madeira granite are derived from the same magma or the early facies (GR and BG) are from one magma, and the later facies (AGB / AGN and GH) from another; (ii) if the origin of the AGB is only due to the AGN autometasomatism or other process were involved (iii) the viability of the hydrothermal hipotesys for the MCD wich implies that deposit occupies spaces generate by AGN corrosion. In the attempt to elucidate some of these questions, a composition-volume relationship are made through to quantify the relative losses and gains between the analyzed pairs of fácies and subfácies The geochemistry mass balance results indicate that higher levels of Si, Na, Li F of the late facies, as well as the differences in behavior of REE, reinforce the idea that the early facies (GR and BG) comes from one magma different from that who originate the later facies (albite granite and GH). The chemical homogeneity of the AGB found in composition-volume relationship, in addiction with the lower concentration of Na, F, H2O, REE, mineral ores and products, suggest an ascension and crystallization of AGB previous to AGN. As consequence AGB forms a different primary paragenesis. The comparison of AGN with DCM using a geochemistry mass balance permitted conclude that to form the DCM is necessary a volume variation of around 20 times. Than, it indicates that to form the massive criolitic deposits was required a corrosion and consumption of the AGN subfacies.
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Ng, Wai Pan. "Petrogenesis, U-Pb zircon geochronology and tectonic evolution of the Malaysian granite provinces in the Southeast Asian tin belt." Thesis, University of Oxford, 2014. http://ora.ox.ac.uk/objects/uuid:0f2f3942-6d64-4a17-b194-08672107aeb2.
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The Malaysian granitoids form the backbone of the Malay Peninsula and have long been recognized as composed of two distinct granitic provinces separated by the Bentong-Raub suture zone:
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Silva, Fernanda Rodrigues da. "Geoquímica e geocronologia U-Pb (SHRIMP) de granitos da região de Peixoto de Azevedo – província aurífera de Alta Floresta – MT." Universidade Federal de Mato Grosso, 2014. http://ri.ufmt.br/handle/1/591.
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A análise de dados petrográficos, geoquímicos e geocronológicos de granitos da região de Peixoto de Azevedo-MT, na porção leste da Província Aurífera de Alta Floresta, conduziu ao reconhecimento de dois corpos graníticos limitados por grandes falhamentos e zonas de cisalhamento regionais. Na porção noroeste, ocorre um corpo com dimensões de aproximadamente 50 km², caracterizado como biotita granodiorito, de granulação grossa, textura inequigranular a porfirítica, metaluminoso à peraluminoso, cálcio-alcalino de alto potássio e magnesiano. Na porção sudeste da área, ocorre um corpo com aproximadamente 100 Km², caracterizado como biotita monzogranito, de granulação grossa, textura equigranular a porfiritica, levemente peraluminoso, cálcico-alcalino de alto potássio e caráter dominantemente ferroso. Datações U-Pb (SHRIMP em zircão) realizadas neste trabalho, mostraram que o biotita monzogranito apresenta uma idade de 1869±10 Ma, o que permitiu incluí-lo como parte da Suíte Intrusiva Matupá, enquanto o biotita granodiorito apresentou idade de 1761±12 Ma, cronocorrelata a idade da Suíte Intrusiva Teles Pires. Entretanto devido as variações composicionais, manteve-se para o granodiorito a denominação de Granito Peixoto. As duas unidades mostram padrões de Elementos Terras Raras com enriquecimento de leves sobre pesados e anomalia negativa de Eu (Lan/Ybn 7,6 a 17,31 e razões Eu/Eu* entre 0,46-0,72 para o biotita monzogranito e Lan/Ybn 7,13 a 29,09 com razões Eu/Eu* entre 0,25-0,40 para o biotita granodiorito). Os elementos-traço para ambos, apresentam anomalias negativas de Ba, P, Ti e Nb indicando uma evolução por fracionamento mineral onde há participação de plagioclásio, apatita e titanita e ou ilmenita, onde a anomalia negativa de Nb está relacionada a herança de placas subductadas. Duas hipóteses são sugeridas para os granitos da região. A primeira supõe que o arco magmático denominado Juruena, inicia com a formação dos granitos da Suíte Intrusiva Matupá (1870 Ma) e prossegue até a idade do granodiorito Peixoto (1761 Ma). A variação composicional gerada no período de 1870 Ma até 1761 Ma é justificada pela presença de uma crosta heterogênea, retrabalhada durante a subducção. A segunda hipótese considera que apenas o monzogranito foi gerado em ambiente de margem continental ativa, num estágio maduro. O granodiorito provavelmente teria se originado em estágio pós-colisional, como resultado de fusão de placa litosférica delaminada, seguida de contaminação crustal. A primeira hipótese têm como base a ausência de evidências de zonas colisionais na região. Entretanto na hipótese 2, considera-se que a ausência de assinaturas colisionais pode estar relacionada à baixa taxa de exumação crustal ou a carência de estudos geológicos.
The analysis of petrographic, geochemical and geochronological data of granites in the region of Peixoto de Azevedo - MT, in the eastern portion of the Alta Floresta Gold Province, led to the recognition of two granitic bodies bounded by major faults and shear zones in the region. In the northwestern portion, a body with dimensions of approximately 50 km ², featured as biotite granodiorite , coarse-grained , porphyritic texture inequigranular to, metaluminous to peraluminous, calc- alkaline high potassium and magnesium occurs. In the southeastern portion of the area, a body with approximately 100 Km ², featured as biotite monzogranite, coarse-grained, equigranular to porphyritic texture, slightly peraluminous, calc- alkaline high potassium and occurs dominantly ferrous character. U- Pb dating ( SHRIMP zircon ) in this work showed that the biotite monzogranite has an age of 1869 ± 10 Ma, which allowed to include it as part of Intrusive Suite Matupá, while the biotite granodiorite had age 1761 ± 12 Ma, cronocorrelata age Intrusive Suite Teles Pires. However due to compositional variations, remained for the designation of granodiorite Granite Peixoto. Both units show patterns of Rare Earth Elements with enrichment of light over heavy and negative Eu anomaly ( Lan / YBN 7.6 to 17.31 and ratios Eu / Eu * between 0.46 to 0.72 for biotite monzogranite and Lan / YBN 7.13 to 29.09 with ratios Eu / Eu * between 0.25-0.40 for the biotite granodiorite ). Trace elements for both present negative anomalies of Ba, P, Ti and Nb indicating an evolution for mineral fractionation where there is involvement of plagioclase, apatite and titanite and ilmenite or where the negative Nb anomaly is related to inheritance subductadas plates. Two hypotheses are suggested to the granites of the region. The first assumes that the magmatic arc called Juruena, begins with the formation of granites Intrusive Suite Matupá (1870 Ma ) and continues until the age of granodiorite Peixoto ( 1761 Ma ). The compositional variation generated in the period from 1870 Ma to 1761 Ma is justified by the presence of a heterogeneous crust reworked during subductio. The second hypothesis considers that only the monzogranite was generated in active continental margin environment, in a mature stage. The granodiorite probably would have originated in post -collisional stage, as a result of fusion of delaminated lithospheric plate , followed by crustal contamination. The first hypothesis are based upon the absence of evidence for collisional zones in the region. However in case 2, it is considered that the absence of collisional signatures may be related to the low rate of crustal exhumation or the lack of geological studies.
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Pawlig, Sabine. "Geological evolution of the Monte Rosa constraints from geochronology and geochemistry of a talc kyanite chloritoid shear zone within the Monte Rosa granite (Monte Rosa nappe, Italian Western Alps) /." [S.l.] : [s.n.], 2001. http://ArchiMeD.uni-mainz.de/pub/2001/0137/diss.pdf.
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Nogueira, Shayenne Fontes. "Petrologia, geocronologia (U-Pb SHRIMP) e geologia isotópica (Sm-Nd) do granito aquidabã- arco magmático amoguijá-terreno rio Apa- Sul do Cráton Amazônico." Universidade Federal de Mato Grosso, 2015. http://ri.ufmt.br/handle/1/113.
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CNPq
O Terreno Rio Apa é marcado por uma história evolutiva complexa e ainda contêm problemáticas a serem estudadas e compreendidas. Neste trabalho são apresentados os resultados obtidos a partir da caracterização petrológica do Granito Aquidabã que pertence à Suíte Intrusiva Alumiador inserida no Arco Magmático Amoguijá deste terreno. Em um contexto anterior, as rochas deste granito eram descritas como pertencentes ao Batólito Alumiador, porém, as mesmas apresentam características singulares que levaram à sua individualização. O Granito Aquidabã está representado por rochas plutônicas e efusivas, de natureza ácida. São classificadas como dacitos e riolitos, riolitos/riolitos alcalinos e adamelitos (monzogranitos)/granitos, subdivididos em três fácies petrográficas: Granito Gráfico (fácies 1), Subvulcânicas Dacítica-Riolítica (fácies 2), Microgranito (fácies 3). A primeira é, volumetricamente, dominante no corpo mapeado sustentando as partes mais elevadas, e disposta na porção central da Serra da Alegria; caracteriza-se por rochas maciças e de cor rosa a rosa-acinzentado, leucocráticas, equi- a inequigranulares média a fina. A fácies 2 é caracterizada pela ocorrência de litotipos que variam de dacitos a riolitos.Os dacitos apresentam-se marrom-acinzentado, com textura porfirítica, destacando fenocristais de plagioclásio e quartzo, por vezes com dimensões entre 1 e 7 mm apresentando, comumente, feições de corrosão magmática como golfos e embaiamentos, envoltos por uma matriz felsítica cinza. Os riolitos são rosa-acinzentado, maciços, afaníticos, com variedades porfiríticas, apresentando fenocristais de feldspato alcalino com tamanhos entre 1 e 5 mm envoltos por uma franja esferulítica de composição quartzo+K-feldspato. A fácies Microgranito (fácies 3) é a de menor representatividade, sendo encontrada nas bordas oeste e sudoeste do corpo granítico, caracterizada por rochas maciças cinza-claro, inequigranulares fina a muito fina. Os dados geoquímicos sugerem um magmatismo de composição compatível com a de granitoides tipo A gerados em ambiente de arco magmático, em período pós-tectônico. Através do método geocronológico U-Pb (SHRIMP) em zircão se obteve idade de 1811±6,8 Ma para o Granito Aquidabã, com valores εNd (1,81Ga) de -2,18; -4,37 e -1,50, e idade modelo TDM de 2,35, 2,57 e 2,26 Ga que apontam para participação de uma fonte crustal na origem do magma, possivelmente envolvendo processos de fusão parcial de uma crosta continental neoarqueana a paeloproterozoica na geração do granito. Os resultados obtidos apontam que o Granito Aquidabã corresponde a um magmatismo desenvolvido no final do Orosiriano no Arco Magmático Amoguijá.
The Rio Apa Terrane is marked by a complex evolutionary history and still contain issues to be studied and understood. This paper presents the results obtained from the petrologic characterization of Aquidabã granite belonging to Intrusive Suite Alumiador inserted into the Magmatic Arc Amoguijá. In a previous context, this granite rocks were described as belonging to the Batholith Alumiador, however, they present unique characteristics that led to its individualization. The Aquidabã Granite is represented by plutonic and effusive rocks, acidic in nature. They are classified as dacites and rhyolites, rhyolites / alkaline rhyolites and adamelitos (monzogranites) / granite, divided in three petrographic facies: Graphic Granite (facies 1), Subvolcanic Dacitic-Riolítica (facies 2), Microgranito (facies 3). The first is volumetrically dominant in the body, arranged in the central portion of the Serra da Alegria; It characterized by massive rocks and pink , pink-gray, leucocratic, inequigranular thin.The facies 2 is characterized by the occurrence of rock types ranging from the dacites, dacites/riolitos. Have color grayish to brown, with phenocrysts of quartz and plagioclase, sometimes with dimensions between 1 and 7 mm, presenting features magmatic corrosion as gulfs and embayments, surrounded by a gray matrix felsítica.The rhyolites are pink-gray, massive, afaníticos with porphyritic varieties, with phenocrysts of alkali feldspar with sizes between 1 and 5 mm surrounded by a fringe spherulitic quartz K-feldspar + composition. The Microgranito facies (facies 3) is the smaller representation, found in the western and southwestern edges of the granite body, characterized by light gray massive rocks, thin inequigranular very thin. The geochemical data suggest a composite magmatism compatible with the granitic type A generated in magmatic arc environment in post-tectonic period. Through the method geochronological U-Pb (SHRIMP) was obtained zircon age ± 6.8 1811 Ma to Aquidabã Granite with εNd values (1,81Ga) of -2.18; -4.37 And -1.50, and TDM model age of 2.35, 2.57 and 2.26 Ga pointing to involvement of a crustal magma source in origin, possibly involving partial melting processes of continental crust neoarqueana the paeloproterozoica in granite generation. The results suggest that the Aquidabã Granite corresponds to a magmatism developed in the late Orosirian in Magmatic Arc Amoguijá.
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Redes, Letícia Alexandre. "Granito Taquaral : evidências de um arco magmático orosiriano no sul do Cráton Amazônico na região de Corumbá - MS." Universidade Federal de Mato Grosso, 2015. http://ri.ufmt.br/handle/1/117.
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CAPES
O Granito Taquaral possui dimensões batolíticas, localiza-se no sul do Cráton Amazônico, na região de Corumbá, extremo ocidente do estado de Mato Grosso do Sul, próximo ao limite Brasil-Bolívia, sendo parcialmente recoberto pelas rochas sedimentares das formações Urucum, Tamengo, Bocaina e Pantanal e pelas as Aluviões Atuais. Com base no estudo das rochas do Granito Taquaral a partir de granulação, cor e composição, juntamente com o mapeamento geológico de detalhe, foi realizada a identificação de três fácies petrográficas: Fácies Média a Grossa Cinza, Fácies Grossa Rosa e Fácies Fina Rosa. A primeira é, volumetricamente, dominante no corpo mapeado; caracteriza-se por rochas leucocráticas, de cor cinza, textura inequi a equigranular média a grossa, às vezes, mostra-se milonitizada e são classificadas como quartzo-monzodiorito, granodiorito e monzogranito. A segunda é constituída por rochas leucocráticas de cor rosa, inequigranulares, grossas, de composição quartzo-monzonito e monzogranito. Enquanto que a terceira é composta por rochas hololeucocráticas de cor rosa-claro, equi a inequigranulares classificadas como monzo a sienogranítica, de granulação fina e representadas por diques aplíticos. Localmente são encontrados dois tipos de enclaves de natureza e origens diferentes, um de composição máfica, corresponde a xenólito e outro, identificado como Enclave Microgranular Félsico. Na área de estudo são encontrados, também diques de diabásio sempre em contatos abruptos com o granito. Foram identificadas duas fases deformacionais, uma de natureza dúctil (F1) e outra rúptil/rúptil-dúctil (F2). Os dados geoquímicos indicam composição intermediária a ácida para essas rochas e sugerem sua colocação em ambiente de arco, representando um magmatismo cálcio-alcalino de médio a alto-K, metaluminoso a peraluminoso. Através do método geocronológico U-Pb (SHRIMP) em zircão se obteve idade de 1861±5,3 Ma para sua cristalização. Análises Sm-Nd em rocha total fornecem valores de εNd(1,86 Ga) de -1,48 e -1,28 e TDM de 2,32 e 2,25 Ga apontando para uma provável fonte crustal riaciana. Os resultados obtidos apontam que o Granito Taquaral corresponde a um magmatismo desenvolvido no final do Orosiriano no Arco Magmático Amoguijá.
The Taquaral Granite comprises an intrusion of batholithic dimensions, located in the south of the Amazon Craton in Corumbá region - far west of the state of Mato Grosso do Sul, near the border between Brazil and Bolivia -, partially covered by sedimentary rocks of the Urucum, Tamengo, Bocaina and Pantanal formations and the Alluvial Deposits. Based on grain size, color, and composition along with detailed geological mapping, three petrographic facies are attributed to the rocks of Taquaral Granite: Medium to Coarse-grained Grey Facies, Coarse-grained Pink Facies and Fine-grained Pink Facies. The first facies is volumetrically dominant in the mapped body; characterized by leucocratic rocks, grey, inequigranular to equigranular medium-to-coarse grained, sometimes displaying a mylonitized texture and are classified as quartz-monzodiorite, granodiorite and monzogranite. The second facies consists of pink leucocratic rocks, inequigranular, coarse-grained, of quartz monzonite and monzogranite composition. In turn, the third facies consists of light-pink hololeucocratic rocks, equigranular to inequigranular, classified as fine-grained aplite dykes of monzogranitic to syenogranitic composition. Two different types of enclaves are locally found: one corresponds to a mafic xenolith; another is identified as felsic microgranular enclave. In the study area, diabase dikes are also found, always in direct contact with the granite. Two deformation phases are identified, one of ductile behaviour (F1) and another of brittle / ductile brittle behaviour (F2). Geochemical data indicate intermediate to acid composition for these rocks and suggest an arc environment, representing a medium to high-K calc-alkaline magmatism, metaluminous to peraluminous. SHRIMP U-Pb zircon ages of 1861 ± 5.3 Ma are attributed to crystallization. Sm-Nd whole rock analyses provided negative εNd(1.86 Ga) values (-1.48 and -1.28) and TDM model ages from 2.32 to 2.25 Ga indicating a Rhyacian crustal source. The results indicate that Taquaral Granite is an evidence of a magmatism developed in the Amoguijá Magmatic Arc in late Orosirian.
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Serrano, Julien. "Origine des pegmatites du Cap de Creus : approche intégrée de terrain, pétrologie et géochimie." Thesis, Toulouse 3, 2019. http://www.theses.fr/2019TOU30332.
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Depuis plusieurs décennies, le débat sur l'origine de formation des pegmatites a conduit à l'élaboration de deux modèles, un modèle granitique et un modèle anatectique. Bien que ces modèles soient communément admis par la communauté scientifique, ils s'appuient majoritairement sur des critères géochimiques et/ou pétrologiques, occasionnellement sur des critères géochronologiques, et rarement sur des critères structuraux. Le but de ma thèse est d'étudier et de déterminer l'origine -granitique vs anatectique- des pegmatites du Cap de Creus (Espagne) en combinant travaux structuraux et géochimiques. Les analyses in-situ (microsonde, LA-ICPMS) combinées aux différentes mesures structurales et observations microstructurales, à la fois dans les pegmatites et leurs encaissants, m'ont permis non seulement d'établir une chronologie relative de mise en place des pegmatites, mais également de replacer l'origine des pegmatites du Cap de Creus dans un modèle géodynamique régional, mettant ainsi en évidence deux champs de pegmatites d'origines différentesSince several decades, the debate on the origin of pegmatite formation has led to the development of two models, a granitic model and an anatectic model. Although these models are commonly accepted by the scientific community, they rely mainly on geochemical and/or petrological criteria, occasionally on geochronological datas, and rarely on structural criteria. The aim of my thesis is to study and to determine the origin -granitic vs anatectic- of the Cap de Creus pegmatites (Spain) by combining structural and geochemical studies. In-situ analyses (microprobe, LA-ICPMS) combined with different structural works and microstructural observations, both in pegmatites and their host rock, allowed me to establish a relative chronology of pegmatite emplacement, but also to replace the origin of the Cap de Creus pegmatites in a regional geodynamic model, thus highlighting two pegmatite fields of different origins
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Gamil, Ali Saif. "Petrology and geochemistry of Shetland granites." Thesis, University of Liverpool, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.316890.
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This study is concerned with the distribution, age, chemistry and geotectonic setting of the 21 granites in Shetland. The granites range in size from a few metres to 8 Km across and in age from Pre-Moine to early Carboniferous. The granites occupy a unique position in being placed approximately half way between Scotland and Norway Caledonides and about 320 Km east of southeast coast of Greenland, if Greenland is restored to its pre-continental Drift position as predicted by the best fit of Greenland and Europe. The Shetland granites have been subdivided into 5 groups according to their location to the east or west of Walls Boundary Fault ( a continuation of Great Glen Fault), mineralogical content and their occurrence in situ as granitic pebbles, as follows; Granites to the east of WBF include (1) hornblende-bearing granites (2) hornblende-free granites and (3) Granitic pebbles a) the Rova Head conglomerate & b) the Funzie conglomerate. Granites to the west of WBF include (4) Ronas Hill granite and its satellites and (5) Sandsting & Bixter granites which are grouped together because of their proximity and because the Bixter granite seems to be the acidic end product of the Sandsting granitoid. A detailed petrological and geochemical study has been made of each group. Samples from each occurrence have been examined for mineralogical content and analysed by a variety of methods for major and trace elements (XRF, INAA, RNAA). This infonnation has been used to derive the mechanisms which may have been responsible for the observed differentiation trends. To the east of the Walls Boundary Fault (WBF) are hornblende-bearing granites, hornblende-free granites and Funzie and Rova Head granitic pebbles. The hornblende-bearing granites are truncated by the WBF and characterized by high Sr and Ba values. The Spiggie granite within this hornblende-bearing group also contains considerable amounts of primary epidote. The hornblende-free granites are a miscellaneous group of granitic rocks ranging between two-mica granites and garnet bearing granites, albite keratophyre and trondhjemite dykes. To the west of WBF are Ronas Hill granophyre and its satellites (with drusy cavities containing crystals of stilpnomelane, quartz and epidote), Sandsting complex and Bixter granites. Major element modelling suggests that a plagioclase, biotite and hornblende fractionation process is appropriate for hornblende-bearing granites and Sandsting granite. Graphical and trace element modelling do not conflict with this too, but rare earth element modelling requires extraction of a quartz-feldspar phase. The classification of Shetland granitoids on the basis of ages and petrology has not been previously attempted. According to the Read classification, the Caledonian hornblende-free granites could be classified as Pretectonic and Syntectonic intrusions equivalent to his older granites. In contrast to the hornblende-bearing granites to the east ofWBF (Graven, Brae complexes and the Spiggie granite), the Graven and Brae appear to belong to the Appinite Suite while the Spiggie granite seems to be a forceful Newer Granite. According to Read the forceful Newer Granites were emplaced just after the Appinite Suite but in Shetland the Graven and Spiggie granites appear to be the same age (400 Ma). The Ronas Hill granite and its satellites, Sandsting and Bixter granites to the west of WBF are Upper Devonian granites and equivalent to the permitted last intrusions of Read, but do not appear to be of the caulderon or ring complex type typical of those in Scotland In terms of ages the hornblende-bearing granites have given K-Ar ages of about 400-430 Ma. The Ronas Hill granite and its satellites, Sandsting complex and Bixter granite give K-Ar ages about 360 Ma. Consideration of typology indicates that the hornblende-bearing granites, Ronas Hill & its satellites, the Sandsting complex and Bixter granite are I-Caledonian type whereas some of the hornblende-free granites are close to S-type. On the De La Roche classification system the Shetland granites are high-K calc-alkaline (except trondhjemite dykes and keratophyre in the hornblende-free granites group) and mostly plotted in the shoshonitic trend The geochemical comparison of the the post Devonian Ronas Hill granite and its satellites on the one hand and the closely associated late Devonian Shetland volcanics on the other, reveals that there is no link between them. A comparison of the Shetland and Scottish granitoids in terms of major, trace and rare earth elements reveals very close similarities between these two Caledonian regions. Both show the same high K-calc-alkaline (peccerillo & Taylor, 1976), the high alumina and alkali (Kuno, 1966) character, also show a general alkali-calcic character (Peacock, 1930) and they also have very good correlation in terms of some trace element variation diagrams such as Sr and Ba
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Ghosh, Amiya Kumar. "Reconnaissance U-Pb geochronology of Precambrian crystalline rocks from the northern Black Hills, South Dakota: Implications for regional thermotectonic history." [Kent, Ohio] : Kent State University, 2009. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=kent1240007954.
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Thesis (M.S.)--Kent State University, 2009.Title from PDF t.p. (viewed Feb. 12, 2010). Advisor: Peter Dahl. Keywords: Black Hills; Crook Mountain granite; Homestake gold mine; gold mineralization; magmatism; metamorphism; metapelite; g monazite; zircon; titanite; geochronology; thermotectonism Includes bibliographical references (p. 97-106).
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Bueno, Juliana Finoto. "Geoquimica e cronologia de alojamento de granitos colisionais na Faixa Sergipana, Nordeste do Brasil." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/287312.
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Orientador: Elson Paiva de OliveiraTese (doutorado) - Universidade Estadual de Campinas, Instituto de Geociencias
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Resumo: A Faixa Sergipana é uma das mais significantes faixas móveis neoproterozóicas do nordeste do Brasil, porque ela contém diversas estruturas e domínios litológicos que permitem que ela seja comparada a orógenos fanerozóicos como os Himalaias, por exemplo. A Faixa Sergipana foi formada durante a colisão entre o Cráton São Francisco-Congo e o Maciço Pernambuco-Alagoas durante a orogênese Brasiliano/Pan-Africano é formada por cinco domínios litoestruturais (Canindé, Poço Redondo-Marancó, Macururé, Vaza Barris e Estância) e é um orógeno chave para a reconstrução de parte da história do Gondwana Oeste. São reconhecidos três eventos de deformação principais (D1-D3) nas rochas supracrustais da Faixa Sergipana, sendo que o evento D2 é o principal evento colisional na faixa e associado a ele tem-se a geração de grande parte dos granitos presentes nos domínios Macururé e Poço Redondo-Marancó. Os granitos presentes nestes domínios foram divididos em dois grupos principais: (1) os granitos com ~ 625 Ma compostos pelos: (i) granitos com características de arco no Domínio Poço Redondo-Marancó (Granodiorito Queimada Grande) e no Domínio Macururé (Tonalito Camará e Granodiorito Coronel João Sá) e (ii) granitos com características crustais do Domínio Poço Redondo- Marancó (granitos Sítios Novos e Poço Redondo) e (2) os granitos colisionais do Domínio Macururé de ~ 580 Ma. Os granitos Queimada Grande, Camará e Coronel João Sá são plutons de alto potássio, cálcioalcalinos, metaluminosos, magnesianos, tipo-I de arco vulcânico. Estes granitos foram originados por fusão parcial de rochas derivadas do manto ou de crosta inferior de composição basáltica com proporções variáveis de contaminação com crosta continental. Os granitos Sítios Novos e Poço Redondo foram gerados pela fusão dos migmatitos locais e os granitos colisionais do Domínio Macururé por alta taxa de fusão dos micaxistos encaixantes. A abundância de granitos colisionais no Domínio Macururé indica que este domínio pode ter funcionado como um conduto dúctil, durante o neoproterozóico, limitado por zonas de cisalhamento regionais. Para delimitar a duração da colisão que resultou na formação da Faixa Sergipana foi utilizada a idade obtida para o Tonalito Camará pré- D2 de 628±12 Ma, que marca a idade máxima para o início do evento D2, e a idade do Granito Pedra Furada sin a tardi- D2 de 571±9 Ma, que marca a idade mínima para o final do evento D2; utilizando estes dados tem-se que o principal evento colisional (D2) na Faixa Sergipana durou pelo menos 57 Ma. Os granitos Queimada Grande, Camará e Coronel João Sá são o registro de arco continental na Faixa Sergipana formado durante a colisão neoproterozóica e a sua presença indica que o Domínio Macururé estava conectado ao Domínio Poço Redondo-Marancó antes do início da orogênese Brasiliana.
Abstract: The Sergipano Belt is one of the most significant Precambrian orogenic belts of Northeastern Brazil because it contains several structural and lithologic domains that allow it to be compared with Phanaerozoic orogens, like Himalayas. The Sergipano Belt was formed through continental collision between the Congo- São Francisco Craton and the Pernambuco-Alagoas Massif during the Brasiliano/Pan-African Orogeny and it comprises five lithostructural domains: Canindé, Poço Redondo-Marancó, Macururé, Vaza Barris and Estância and it is a key belt for reconstructing part of the history of West Gondwana. Three main events of regional deformation (D1-D3) are recognized in the supracrustal rocks of the belt and the D2 event is the main collision event in the belt, most granites were emplaced during this event in the Macururé and Poço Redondo-Marancó domains. Granites found in these domains can be divided into two groups: (1) ~ 625 Maold granites formed by: (i) arc-type granites in the Poço Redondo-Marancó domain (Queimada Grande Granodiorite) and in the Macururé Domain (Camará tonalite and Coronel João Sá granodiorite) and (ii) crustal granites in the Poço Redondo-Marancó domain (Sítios Novos and Poço Redondo granites) and (2) ~ 580 Ma-old collision-related granites in the Macururé domain. The Queimada Grande, Camará and Coronel João Sá granites are plutons of high-K calc-alkaline, metaluminous, magnesian, I-type volcanic arc granites. These granites were originated by partial melting of basic crustal sources derived from mantle or lower crust of basaltic composition with variable ratios of continental crust contamination. The Poço Redondo and Sítios Novos granites were generated by partial melting of local migmatites and the collisional granites of the Macururé domain by high degree of partial melting of the Macururé micaschists. The abundance of collisional granites in the Macururé domain indicates that this domain acted as a ductile channel flow during the Neoproterozoic limited by regional. To delimit the collision duration that results in the formation of Sergipano belt was used the 628±12 Ma age obtained for the pre-D2 Camará Tonalite, which mark the maximum age for beginning of D2 event, and the 571±9 Ma age obtained for the syn- to tardi- D2 Pedra Furada granite that mark the minimum age for end of the D2 event; using these numbers without the associated errors, we conclude that the main Neoproterozoic collisional (D2) event in the Sergipano Belt may have lasted at least 57 million years. The Queimada Grande, Camará and Coronel João Sá granites are the record of continental arc in the Sergipano belt formed during the Neoproterozoic collision and its presence indicates that the Macururé domain was connected in the Poço Redondo-Marancó domain before the beginning of the Brasiliano orogeny.
Doutorado
Metalogenese
Doutor em Ciências
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Ghani, Azman Abdul. "Petrology and geochemistry of Donegal granites Ireland." Thesis, University of Liverpool, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243112.
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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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Amorim, Lucas Eustáquio Dias. "O granito São Timóteo no perfil Monsenhor Bastos, província uranífera de Lagoa Real: mineralogia, geoquímica e fluidos." CNEN - Centro de Desenvolvimento da Tecnologia Nuclear, Belo Horizonte, 2012. http://www.bdtd.cdtn.br//tde_busca/arquivo.php?codArquivo=311.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorForam estudados corpos graníticos localizados no setor Monsenhor Bastos, porção sudoeste da Província Uranífera de Lagoa Real (PULR). A amostragem foi desenvolvida nas pedreiras de Lagoa Linda (LL), Pedreira Nova (PN) e no granitoide Lajedo (GR) este ultimo que aflora imediatamente a leste da anomalia uranífera AN02. O trabalho focaliza aspectos mineralógicos, geoquímicos, tipológicos e de fluidos desses granitoides, a fim de classificá-los mineralogica, textural e quimicamente. Foram utilizadas as metodologias de petrografia, microssonda eletrônica, geoquímica, termobarometria e estudo de inclusões fluidas (IF). As amostras de granitos apresentam uma paragênese magmática composta por feldspato potássico, plagioclásio, quartzo, piroxênio, ilmenita 1 e zircão. Também foram identificadas duas fases pós-magmáticas compostas por anfibólio, biotita, granada, allanita, ilmenita 2, kainosita, parisita. A ocorrência desses eventos pós-magmáticos propiciou também a formação de uma segunda geração de plagioclásio, zircão, além da formação de mirmequitas e a recristalização de parte dos feldspatos e quartzo. O anfibólio estudado foi formado por alteração do piroxênio em contato com o fluido do primeiro evento pós-magmático. A biotita foi gerada a partir da alteração do anfibólio. No mesmo período de formação do anfibólio foi gerada a allanita, sendo que a parisita e kainosita formaram-se pela alteração desta durante um evento pós-magmático. O evento pós-magmático mais antigo está associado a fluidos ricos em F e Cl, com baixo fO2, pressão próxima a 7 Kbar e temperatura inferior a 700 oC. A parte final desse evento esta associado a soluções alcalinas, ricas em CO2, com temperaturas no intervalo entre 480 C e 600 oC. O estudo de IF permitiu caracterizar fluidos tardios aprisionados no quartzo, que podem estar relacionados com o segundo evento pós-magmático. Esses fluidos, de provável origem hidrotermal, é bastante semelhante ao encontrado por Fuzikawa et al (1988), nas IF dos veios de quartzo que cortam os gnaisses da PULR. A geoquímica permitiu classificar os granitos como sienogranitos / quartzo sienitos, metaluminosos, alcalino-cálcicos (na fronteira dos calci-alcalinos), plotando na série shoshonitica. Também foram classificados como granitos Tipo A, não evoluídos e ferroan. Os dados obtidos não permitem classificar os granitos São Timóteo como rapakivi. Entretanto, a composição desses granitos é equivalente, em termos de elementos maiores e elementos traços, aos granitos rapakivi Cigano e Serra dos Carajás, fases menos especializadas da Suíte Serra dos Carajás. Finalmente, ressalta-se a clara necessidade do desenvolvimento de estudos metalogenéticos, geoquímicos e isotópicos que permitam conhecer com aprofundamento a composição e evolução da Suíte magmática de Lagoa Real e sua relação com as mineralizações de urânio.
Granitic bodies located in the Monsenhor Bastos sector, southwestern portion of the Lagoa Real Uranium Province (PULR) were studied. The sampling was developed in the quarries of Lagoa Linda, Pedreira Nova and Lajedo granitoids that outcrop immediately east of the uranium anomaly (AN02). The work focused on the mineralogical, geochemical, and fluid typological aspects of these granitoids in order to classify them mineralogical, textural and chemically. Petrography, electron microprobe, geochemical, thermobarometry and study of fluid inclusions (FI) methods were performed. The granite shows a magmatic paragenesis with potassium feldspar, plagioclase, quartz, pyroxene, ilmenite and zircon. Two post-magmatic stages composed of amphibole, biotite, garnet, allanite, ilmenite, kainosite, parisite were also identified. The occurrence of post-magmatic events has also led to the formation of a second generation of plagioclase, zircon, besides mirmequites formation and recrystallization of feldspar and quartz. The amphibole was formed by the alteration of pyroxene in contact with the first post-magmatic fluid event. The biotite was generated from the alteration of the amphibole. Allanite was generated in the same period of the amphibole formation, while parisite and kainosite were formed from allanite alteration during a pós-magmatic event.. The post-magmatic oldest event is associated to low fO2, near 7 Kbar pressure, below 700 oC temperature F and Cl rich fluids. The final part of this event is associated to alkaline solutions, rich in CO2, with temperatures between 480 C and 600 oC. The FI studies allowed to characterize late fluids trapped in quartz, which may be related to the second post-magmatic event. This fluid, probably of hydrothermal origin, is quite similar to one found by Fuzikawa et al (1988), in FI found in quartz veins cutting the PULR gneisses. The geochemistry allowed to classify the granites as sienogranites / quartz syenites, metaluminous, alkali-calcic (the border of calc-alkaline) and plotting in shoshonitic field. Granites were also classified as Type A, unevolved and ferroan. The data do not allow the classification of São Timóteo granite as rapakivi type. However, the composition of these granites is equivalent, in terms of major and trace elements, to the Cigano and Serra dos Carajas rapakivi granites, less specialized phases of Serra dos Carajás suite. Finally, it emphasizes the clear need for further metallogenesis, geochemical and isotopic studies depth as to show the composition and evolution of magmatic suite of Lagoa Real and its relationship to uranium mineralization.
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Hammad, H. M. "Petrology and geochemistry of some alteration processes in Cornish granites, South-West England." Thesis, University of Southampton, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381218.
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Bakhsh, Rami A. M. "Granites from the midyan terrain, NW Saudi Arabia: petrology, geochemistry and geochronology." Thesis, University of London, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.589422.
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Granites from the Midyan terrain, NW Saudi Arabia: Petrology, geochemistry and geochronology Five, Neoproterozoic, poorly-studied felsic intrusives from NW Saudi Arabia have been subjected to a detailed geological study to understand their characteristics, evolutionary history, tectonic setting, ages and economical potential for rare metal mineralization. The work has utilized field observations, mappmg, mineralogy, petrography, geochemistry (ICP-AES and MS, XRF, scanning electron microscopy and microprobe) and geochronology (Rb/Sr whole rock isochrons and U-Pb zircon analysis). The results have indicated that the individual plutons in the region are each quite different. This is mainly displayed by the existence of different types of granites, based on chemistry and petrography (peralkaline, alkaline and calc-alkaline) and mineralogy (particularly the presence of different types of amphibole, both sodicand calcic). The plutons probably formed at low crystallizaton pressures (~ 1.2 to 3.4 Kbar) and at shallow (~4 to 12 km ±O.5 km) depths, but seem to have been derived from similar source regions. The granites were most likely derived by low-pressure, partial melting of crustal rocks with possible crustal contamination, followed by fractional crystallization and later sub-solidus alteration by fluids. The plutons' ages span a range from 630Ma (Cryogenian) to 554Ma (Ediacaran). The geochemical differences between the granites could be related to their formation during different stages of the region's evolution. A gradual change in tectonic setting is indicated, from island arc accretion in the middle stages of the Panafrican orogen, to a post-collisional setting in the early stages of the Panafrican event. Economically, the granites contain relatively high contents of rare earths elements (REEs) and rare-metals (RMs), mostly hosted by phosphates (monazite-Ce and xenotime), Nb-oxide (fergusonite- Y) and possible rare earth carbonates (synchysite). These elevated REEs and Nb contents and their mineralogical forms highlight the presence of suitable exploration targets for rare earth elements late stage deposits. xiii
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Nogueira, Camila Cardoso. "Caracterização do maciço Santa Clara no município de Cujubim (RO) com base em litogeoquímica, geocronologia e estudos isotópicos." Universidade do Estado do Rio de Janeiro, 2012. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=4130.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorA Suíte Intrusiva Santa Clara está inserida na Província Estanífera de Rondônia, na porção SW do Cráton Amazônico. Essa suíte intrusiva é composta pelos maciços Santa Clara, Oriente Velho, Oriente Novo, Manteiga-Sul, Manteiga-Norte, Jararaca, Carmelo, Primavera e das Antas. Os litotipos que perfazem a Suíte Santa Clara ocorrem hospedados nas rochas do Complexo Jamari, uma associação polideformada composta por gnaisses ortoderivados e paraderivados. Características observadas em campo e em análises petrográficas permitiram subdividir o Maciço Santa Clara em cinco fácies distintas: fácies porfirítica, fácies isotrópica, fácies fina, fácies piterlítica e fácies viborgítica. Os litotipos observados correspondem a hornblenda-biotita granitos e biotita granitos intermediários a ácidos, com composições médias semelhantes àquelas verificadas para sienogranitos e monzogranitos. Geoquimicamente, três magmas podem ser identificados. O magma menos evoluído corresponde às rochas das fácies porfirítica e equigranular, e o mais evoluído compreende as fácies de granulometria fina e piterlítica. A fácies viborgítica representa o terceiro líquido magmático, e aparentemente é diferente de todas as outras fácies em termos de aspectos de campo e geoquímica. A análise litogeoquímica indica que estes granitoides são subalcalinos, bastante empobrecidos em MgO e exibem caráter metaluminoso a fracamente peraluminoso. Os padrões de elementos-traços evidenciam que tais granitóides possuem alto conteúdo em elementos incompatíveis (Rb, Zr, Y, Ta, Ce) e ETR, com exceção do Eu. Além disso, também exibem leve enriquecimento em LILE, forte depleção em elementos como Sr e Ti, e leve empobrecimento de Ba, indicando que o fracionamento de minerais como plagioclásio e titanita foi importante na evolução do líquido magmático analisado. A anomalia negativa de Nb indica envolvimento de material crustal nos processos magmáticos que geraram estes granitoides. Os litotipos analisados possuem características típicas de granitos tipo-A ferroan, e as razões FeOt/MgO entre 4,27 e 26,22 sugerem tratar-se de uma série de granitos félsicos fracionados. Os padrões de ETR observados para os litotipos analisados exibem um considerável enriquecimento em ETRL, e anomalia negativa de Eu, sugerindo fracionamento de feldspato durante o processo de diferenciação do líquido magmático. Diagramas discriminantes de ambientes tectônicos sugerem que os litotipos do Maciço Intrusivo Santa Clara são típicos de ambiente intraplaca, do tipo-A2, isto é, associados a ambientes pós-colisionais/pós-orogênicos. As características isotópicas observadas para os granitoides do Maciço Santa Clara sugerem que os mesmos foram gerados a partir da fusão parcial de uma crosta inferior pré-existente. As idades U-Pb entre 1,07 e 1,06 Ga são compatíveis com um magmatismo ocorrido nos estágios finais da colagem do supercontinente Rodínia (1,2-1,0 Ga) e estágios finais do Ciclo Orogênico Sunsás-Aguapeí (1320-1100 Ma). Sugere-se ainda que na verdade o Maciço Santa Clara seja formado por uma coalescência das três intrusões graníticas que são representadas pelos três magmas anteriormente descritos.
The Santa Clara Intrusive Suite in the Rondônia Tin Province (SW Amazonian Craton) comprises the Santa Clara, Oriente Velho, Oriente Novo, Manteiga-Sul, Manteiga-Norte, Jararaca, Carmelo, Primavera and das Antas massifs. The rocks of the Santa Clara Intrusive Suite are emplaced in the Jamari Complex, an association of ortho and paragneisses which underwent several and complex metamorphic processes. Characteristics observed during both geological mapping and petrographic analyses allowed, for the first time, to subdivide the Santa Clara Massif (SCM) granitoids into five different facies: porphyry, equigranular, fine-grained facies, pyterlitic and wiborgitic facies. These lithotypes comprise hornblende-biotite granites and biotite granites that range from intermediate to acids, and show compositions similar to syenogranites and monzogranites. Geochemical analyses suggest that these granitoids may be divided into three different magmas, considering field aspects and geochemical characteristics. Therefore, the less evolved magma is represented by porphyritic and equigranular facies, and the most evolved magma comprises both fine-grained and pyterlitic facies. The wiborgitic facies representd the other magma, and is geochemically different from all the others facies. Geochemical analyses also show that the granitoids of the Santa Clara Massif are subalkaline, have very low MgO contents and have metaluminous to slightly peraluminous character. Trace elements patterns show that these granitoids have high contents of incompatible elements (Rb, Zr, Y, Ta, Ce) and REE, with exception of Eu. Moreover, they are also slightly enriched in LILE, strongly depleted in elements such as Sr and Ti, and slightly depleted in Ba, pointing out the importance of plagioclase and titanite fractioning during the evolution of these magmatic liquids. Negative anomalies of Nb, along with other geochemical features, suggest the participation of crustal material in the magmatic processes responsible for these granitoids generation. The lithotypes have typical characteristics of ferroan A-type granites, and FeOt/MgO ratios ranging from 4.27 to 26.22 indicate that these are fractionated felsic granites. REE patterns show a remarkable enrichment in LREE along with negative Eu anomaly. Tectonic discriminant diagrams for the Santa Clara Massif granitoids suggest that these are intraplate granitoids, A2-type, that is, related to post-collisional/post-orogenic settings.The isotopic characteristics observed for the Santa Clara Massif granitoids suggest that these were generated through partial melting of a preexistent lower crust. The U-Pb ages between 1,07 e 1,06 Ga are compatible with a magmatism taken place during the final stages of the supercontinent Rodinia agglutinations and the final stages of the Sunsás-Aguapeí Orogenic Cycle. It is also suggested that the Santa Clara Massif represents the coalescence of three different granitic intrusions, which comprise the magmas described above.
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Brydon, Richard. "TRACING MAGAMTIC PROCESS IN PLUTONIC ENVIRONMENTS: INSIGHT FROM APATITE AND RIFT-RELATED GRANITES." Miami University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=miami1547117312990626.
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Robinson, Christian. "Lago Grande di Monticchio : a palaeoenvironmental reconstruction from sediment geochemistry." Thesis, University of Edinburgh, 1993. http://hdl.handle.net/1842/12872.
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During 1990 a 51 metre core was recovered from Lago Grande di Monticchio, a maar lake in S Italy. This provides a high quality laminated sequence extending back into the Late Quaternary which is being examined by a multidisciplinary group. The project here is concerned with sediment geochemistry as a tool for reconstruction of palaeoenvironmental conditions at this locality. The core was analysed at 10cm resolution using techniques such as X-ray fluorescence (XRF). This has produced a highly detailed record of change reflecting either the last 70,000 or 220,000 years. Organic carbon and biogenic silica are believed to represent biogenic productivity and, in particular, nutrient status in the lake system. It is found that the Holocene is marked by very high concentrations of these components in contrast to the minerogenic glacial sediments. Possible earlier interglacials (e.g. the Eemian) contain significantly lower contents of biogenic matter, suggesting that nutrient conditions may have been somewhat poorer during these times. Alternatively, these periods could represent interstadials within the last glacial cycle. C/N ratios and Hydrogen Index values probably reflect both the source and degree of preservation of the organic matter, but should be interpreted cautiously. The δ13C record for bulk organic matter shows a significant shift to isotopically lighter values during the glacial-Holocene transition, but the profile is difficult to interpret due to the many possible factors involved. Indicators of terrigenous clastic material show that the late-glacial and Holocene sediments have received relatively base-rich clastic material probably derived from contemporary tephra inputs to the catchment. This is marked by ratios such as Na/Al and K/Al which increase in apparent association with increased tephra deposition and Zr/Rb which decreases. The effect of tephra blanketing of the catchment and subsequent release of nutrients is proposed as a cause for the much higher productivity during the Holocene interglacial.
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Appleby, Sarah Kristina. "The origin and evolution of granites : an in-situ study of zircons from Scottish Caledonian intrusions." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3172.
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Granitic magmatism in collision belts is widely regarded as a major mechanism for generating continental crust. This hypothesis can be tested by identifying the source rocks of granitic magmas, and in particular the contribution by pristine mantle material. The complexity of granites, and their susceptibility to post-crystallisation alteration, has until recently provided a major obstacle to progress. Zircon, a common and chemically robust accessory mineral in granitoid rocks, retains a record of the composition of the magma it grew from. Recent developments in microanalysis (ion microprobe and laser ablation ICP-MS) now enable in-situ analysis of zircon crystals at high spatial resolution and precision, providing access to this record at the previously inaccessible intra-crystal scale. The resulting data have enormous potential to provide new insights into the nature and age of source rocks and the processes driving magma evolution. This project used an integrated in-situ O, U-Pb and Hf isotope, trace and rare earth element study of zircon to identify the sources and chart the evolution of two ‘I-type’ (igneous/infracrustal precursor) Scottish late Caledonian (~430-400 Ma) granite plutons. I have constrained models of magma generation, the relative contributions of mantle and crust, the ages and identities of their lower crustal sources, and have shown that the plutons played, at most, a minor role in crustal growth. In addition, I have been able to resolve the extent to which open-system changes like magma mixing affected the magma compositions. The same approach was used in a pilot study of three Caledonian (~460 Ma) ‘S-type’ (sedimentary/supracrustal precursor) granite plutons, which theoretically represent magmas formed by melting of a purely supracrustal source. The data confirm that Dalradian country rocks were the primary source, but reveal remarkable isotopic diversity within and amongst the three plutons. The most important general conclusion from this PhD study is that the complexity and scale of isotopic heterogeneity between plutons, amongst samples of the same pluton, in single samples and within individual crystals is far greater than previously recognised, consistent with the incremental assembly of plutons from multiple melt batches of differing composition, sources and petrogenetic evolution.
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Hoosain, Leyla. "Solubility of gold in granitic melts and partitioning of Au between melt and NaCl-saturated fluid or sulfides." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape8/PQDD_0024/MQ50790.pdf.
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