Dissertations / Theses on the topic 'Igneous intrusives'
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1
Pattison, Christopher Ian. "Igneous intrusions in the Bowen Basin." Thesis, Queensland University of Technology, 1990. https://eprints.qut.edu.au/35967/1/35967_Pattison_1990.pdf.
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Igneous intrusions, in the form of stocks, sills and dykes are abundant in the Bowen Basin. They are predominantly Early Cretaceous in age, exclusively epizonal in origin and range in composition from dolerite to granodioriteldacite. All rock units within the
basin, up to and including the Clematis Group, are intruded to some degree. This study assesses the distribution, form, petrology and mode of emplacement of plutons, igneous sills and dykes occurring in the Bowen Basin, and considers their relationship to
the prevailing structure. The tectonic implications of the findings are then assessed. Igneous sills occur in two geographically distinct domains, one in the northern Bowen Basin and the other in the central Bowen Basin. The sills emanated from pre-existing, north to north-northwest trending reverse faults, and preferentially intruded coal seams.
The boundaries to sill intrusion are marked by major northeast trending basement
structures. These basement structures occur at regular intervals throughout the basin, and correspond with the localisation of plutonic and dyke activity, anomalous structural disturbance, and changes in the gross structure of the basin. They are interpreted as
transfer faults that were inherited from an Early Permian, basin-forming extensional
episode. Petrological evidence indicates that the plutons and sills occurring in the northern Bowen Basin are petrogenetically related, and that a progressive variation in their chemistry occurs across the axis of the basin from east to west. Intrusions in the east belong to the calc-alka1ine rock suite, while those in the west belong to the syenitic suite. This
transition is inte1preted in terms of increased crustal contamination as the magma migrated from a source area to the east along a buried, shallow-dipping detachment
surface that extends under the basin. This detachment was inherited from the above mentioned extensional phase and is intimately linked to structures that penetrate
up-section through the basin succession.
Reactivation of the transfer faults during the Early Cretaceous initiated the emplacement of dykes, and the synchronous development of northeast trending normal and wrenchstyle faults. The dykes exhibit characteristics that indicate they were self-propagating, and can be regarded as good palaeostress indicators. This phase corresponded with a major compressional event that involved the reactivation of pre-existing thrust structures, deformation of the Folded Zone and eastern margins of the Nebo Synclinorium and Mimosa Syncline, and the rapid preferential uplift of the central Bowen Basin region.
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Newman, Rowena Jane. "Igneous and hydrothermal minerals and textures in the offshore Canterbury Basin." Thesis, University of Canterbury. Geological Sciences, 2015. http://hdl.handle.net/10092/10856.
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The Canterbury Basin is located on a passive margin on the east coast of the South Island, developed by the rifting of the New Zealand continental fragment from Antarctica in the Late Cretaceous. Well cuttings produced during petroleum exploration in the offshore Canterbury Basin have been examined for secondary minerals and textures. Minerals and textures have been identified primarily from optical examination in reflected light, with a particular focus on producing high-resolution images. Additional identifications are made using thin sections, SEM, XRD and XRF analysis.
The focus of this study is the Clipper-1 well in the Clipper sub-basin as it contains the most abundant mineralisation and covers the full depth of the Canterbury Basin sedimentary sequence. Examination of cuttings from this well has revealed intrusive igneous carbonates and native metals including iron, aluminium and copper. The trace element concentrations in the igneous carbonates indicates they are derived from crustal material. Textures indicating fluidisation and recrystallisation of sedimentary material are also present.
The proposed mechanism for producing these unusual mineral assemblages is a late Pliocene or younger mafic intrusion into the schist basement of the Canterbury Basin. The igneous carbonates are inferred to be derived from melting of carbonates in the schist. The native metals have been produced from melt due to highly reducing conditions produced by interaction of the intrusion with coal and limestone. The combination of native metals and igneous carbonates with a conspicuous absence of typical silicate igneous rocks is inferred to represent a new type of intrusive environment that has not previously been described in the scientific literature.
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Burns, Claire Elizabeth Graham. "Intrusive igneous control on groundwater in the Triassic sandstones of Northern Ireland." Thesis, Queen's University Belfast, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.669657.
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This thesis describes the processes adopted to form the major conclusion that igneous dykes that traverse the Belfast Groundwater Body impede the movement of groundwater in the aquifer to a significant extent. Chapter one introduces the project and its purpose. Chapters two and three are to a large extent literature based, with Chapter two focusing on generic techniques and examples of relevant research on an international scale, where Chapter three focuses on literature specific to the study are" and facilitates a discussion of aquifer behaviour and the formation of an initial conceptual model for groundwater flow. Chapter four describes the re-appraisal of the geological model for the study area using a recently published airborne magnetic geophysical dataset (Tellus). The progression of this Chapter sees the geological model described in the context of the hydrogeological behaviour of the study area, and a discussion at the end facilitates the description of a geological conceptual model of an igneous dyke and an improved understanding of the processes controlling groundwater movement in the Sherwood Sandstone aquifer. Chapter five uses the conceptual understanding developed from previous chapters to construct a numerical model in FeFlow as a tool to assess aquifer sensitivities. The model described progresses from the most basic homogeneous and isotropic representation of the groundwater flow system, and progresses through nine scenarios to be inclusive of homogeneity (transsmissivity and recharge), homogeneous vertical anisotropy, and with the inclusion of three-tier transmissive igneous dyke zones. Chapter six discusses the findings of the research, drawing comparisons from literature, Tellus, and numerical modelling. The discussion includes the schematic understanding of groundwater movement through the aquifer Inclusive of igneous dykes under various pressures. The discussion ends with some recommendations for the implementation of the conceptual model within an industrial and regulatory context. Chapter seven states the major conclusions formed from the research, and makes recommendations for future work.
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Wigley, Rochelle Anne. "The geochemistry of the Karoo igneous volcanic and intrusive rocks of Botswana." Master's thesis, University of Cape Town, 1995. http://hdl.handle.net/11427/21335.
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Bibliography: pages 183-191.The Mesozoic basalts and dolerites of Botswana underlie an estimated area of 150 000km2 and form part of the Karoo Igneous Province of southern Africa. The distribution of Karoo basalts in Botswana is limited essentially to three main sub-basins, the Central Kalahari Subbasin, northern Botswana and the Tuli Syncline and a major dyke swarm, with a WNW strike, extends across Botswana from the Namibian to Zimbabwean borders. This dissertation is a reconnaissance study which concentrates on the recognition and definition of distinct geocheinical sub-groups within the Karoo volcanic and intrusive rocks of · Botswana. 128 new whole rock samples were analyzed for major and trace element concentrations, in addition to the 70 whole rock analyses from Botswana which were available in the UCT database.· Mineral analyses and rare earth element compositions for selected samples are also presented. The basalts and dolerites of Botswana are assigned to one of the three geochemical lineages, i.e. the low-K20, the high-K20 and the felsite lineages on the basis of Si02, MgO and K20 concentrations. A number of distinct geochemical sub-groups· are recognised within these lineages according to whole rock compositions, normative mineralogy, petrography and outcrop character. The low-K20 lineage is subdivided into two main sub-groups on the basis of the Ti02 and Zr concentrations, i.e. the LTZ- and HTZ-type basalt and dolerite sub-groups. The LTZtype basalt sub-group (with ~2% Ti02 and ~250ppm Zr) represents the bulk of the Botswana dataset where the LTZ basalts of Botswana are shown to be lateral equivalents to the Lesotho Formation basalts of the Central Karoo area, considerably expanding the known outcrop area of this basalt type. Two dolerites are the only samples of intrusive equivalents of this voluminous LTZ basalt type in Botswana.,
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Al-Jawadi, A. F. "Minor igneous intrusions of the Lake District : geochronology, geochemistry and petrology." Thesis, University of Newcastle Upon Tyne, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.376308.
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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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Christodoulou, C. "Petrology of the plutonic rocks of the Macquarie Island Complex /." Title page, contents and abstract only, 1990. http://web4.library.adelaide.edu.au/theses/09PH/09phc556.pdf.
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Miggins, Daniel Paul. "Temporal and geochemical insights related to volcanic and plutonic activity within Big Bend National Park, Texas." To access this resource online via ProQuest Dissertations and Theses @ UTEP, 2009. http://0-proquest.umi.com.lib.utep.edu/login?COPT=REJTPTU0YmImSU5UPTAmVkVSPTI=&clientId=2515.
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Wilson, Kelly. "RARE EARTH ELEMENTS AT HICKS DOME, SOUTHERN ILLINOIS, THEIR MODE OF MINERALIZATION AND RELATIONSHIP WITH IGNEOUS INTRUSIONS." OpenSIUC, 2019. https://opensiuc.lib.siu.edu/theses/2581.
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Rare earth elements (REE) are an increasingly important group of metals due to their role in the development of modern technologies. Despite being abundant within the Earth’s crust recoverable ores are uncommon, and their mineralization isn’t as well understood as other abundant ore types. In this work, the mineralization of REE occurring in outcrop samples at Hicks Dome, a cryptoexplosive feature that resides in the Wauboukigou Alnöite Province in southeastern Illinois, was studied to determine the mode of mineralization and the origin of the REE. Xenotime-(Y) was identified with a scanning electron microscope in an intrusive breccia and emplaced during or shortly after the uplift which created the oval doming of the Paleozoic section. Whole rock REE concentrations from ultramafic dikes at Hicks Dome closely match global averages of lamprophyres and carbonatites, with a steep La to Lu slope, and enrichment of light rare earth elements. Hicks Dome has unique characteristics relative to the other intrusions in the Province, such as elevated REE, Th, and doming. These traits indicate that the dome was more closely related to an intrusive body at depth that sourced heat, volatile gases, and a suite of rare elements. Based on these data, the REE mineralization and thorium associated with the siliceous breccia is directly related to the alkaline ultramafic intrusion at Hicks Dome. The volatile rich, hot fluids emanating from the ultramafic magma supplied REE and thorium were mixed with the regional fluids responsible for the IKFD.
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Hulley, Vierah. "Reactions between country rock xenoliths and the magma of Uitkomst Complex, with implications for the origin of the sulphide mineralisation." Pretoria : [s.n.], 2005. http://upetd.up.ac.za/thesis/available/etd-05282008-101011.
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Cooper, Jennifer Rebecca. "Igneous intrusions and thermal evolution in the Raton Basin, CO-NM contact metamorphism and coal-bed methane generation /." Diss., Columbia, Mo. : University of Missouri-Columbia, 2006. http://hdl.handle.net/10355/4606.
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Thesis (M.S.)--University of Missouri-Columbia, 2006.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file viewed on (February 6, 2007) Includes bibliographical references.
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Moorehead, Anthony J. "IGNEOUS INTRUSIONS AT HICKS DOME, SOUTHERN ILLINOIS, AND THEIR RELATIONSHIP TO FLUORINE-BASE METAL-RARE EARTH ELEMENT MINERALIZATION." OpenSIUC, 2013. https://opensiuc.lib.siu.edu/theses/1240.
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Hicks Dome is a mineralized intrusive center of alkaline ultramafic dikes, plugs and diatreme breccias that produced ~1200 m of structural doming of Paleozoic sedimentary rocks in southeastern Illinois. It is part of an igneous province referred to as the "Wauboukigou Alnöite Province" or "Middle Mississippi Alkaline Province". The 40Ar/39Ar dating of biotite and hornblende from igneous rocks throughout the region has consistently produced crystallization ages of 270 +/- 2 Ma (Early-Middle Permian). Hicks Dome lies near the intersection of two aulacogens, the Reelfoot Rift and the Rough Creek Graben. The igneous rocks in the Hicks Dome area range from dark-green, porphyritic dikes, through dikes with pelletal lapilli, to carbonate cemented breccias with country rock fragments and, locally, phenocrysts or xenocrysts and pelletal lapilli. Magmatic minerals include diopside, pargasite, phlogopite-biotite, titanomagnetite, ilmenite, and apatite, as well as carbonate (ferroan-dolomite - ankerite and calcite) of possible magmatic origin. This mineral assemblage only partly corresponds with other occurrences in the middle Mississippi Valley region igneous province as melilite, garnet, olivine, and perovskite were not identified in the Hicks Dome samples. The Hicks Dome igneous lithotype is defined here as a minette, a type of calc-alkaline lamprophyre. Evidence for this classification includes abundant Al-rich phlogopite-biotite, diopside, and pargasite, and the absence of melilite, garnet, and perovskite. Additionally, plotted Al2O3 vs. TiO2 compositions of biotite-phlogopite form a trend subparallel to that of minettes and alnöites, and Al vs. Ti values for most clinopyroxenes fall in the minette field. Some other igneous occurrences in the region are classified as types of ultramafic lamprophyres. For example, the North Hutson mine (Kentucky) and the Cottage Grove (Illinois) dikes are identified as alnöites and the Wildcat Hills dike (Illinois) is regarded as an aillikite. The Hicks Dome igneous suite contains 23 - 25 wt. % SiO2 and 13 - 21 wt. % CO2, whereas regional igneous rocks contain 33 - 36 wt. % SiO2 and 1 - 2 wt. % CO2. Such high CO2 values and inferred carbonate abundance is likely related to the elevated REE values at Hicks Dome. Finally, Hicks Dome samples show relative depletions in Ti, Nb, Ta, Zr, and Hf on a spider diagram compared to other regional igneous occurrences. These data indicate more variability among provincial igneous rocks than previously realized and perhaps two types of lamprophyres, one a calc-alkaline such as at Hicks Dome, and the other an alkaline ultramafic type. Rock samples from Hicks Dome and the surrounding region that were analyzed far exceed the silica cut-off to be considered a carbonatite (sensu stricto), yet a strong, consistent spatial association of abundant carbonate with igneous rocks throughout the region and similar patterns in LIL (large ion lithophyle), HFS (high field strength) and RE (rare earth) elements with carbonatites worldwide supports that magmatic carbon was part of the lamprophyre system at Hicks Dome. Carbon and oxygen isotope values for carbonate from Hicks Dome and other regional igneous samples do not plot within the field for primary carbonatite or the field for unaltered Mississippian limestone and instead form a broad linear trend between these two reference fields. The observed isotopic trend was possibly due to alteration of primary carbonatite by magmatic-hydrothermal and later low-temperature connate fluids. Parisite and/or synchysite, two REE fluorocarbonates of the bastnäsite group, and xenotime, a Y-(REE) phosphate, were identified in the Hicks Dome samples and occur as fibroradial aggregates in dissolution cavities in fluorite and carbonate and as anhedral crystals infilling microfractures and cleavage planes of phlogopite-biotite and paragasite. These textures clearly indicate the REE minerals are secondary phases most likely resulting from hydrothermal alteration-replacement by magmatic-hydrothermal fluids. A fertile (LREE enriched) lithospheric metasomatized mantle likely sourced the Hicks Dome carbonated alkaline silicate magma that, during emplacement, domed and brecciated the Paleozoic strata, expelled magmatic-hydrothermal fluids, and generated a F-REE mineralizing fluid with abundant carbonate. Igneous activity at Hicks Dome is genetically related to F-REE-base metal mineralization hosted by diatreme breccias, and likely contributed fluorine to the connate brines responsible for the F-base metal mineralization of the surrounding Illinois-Kentucky Fluorspar District (IKFD). Although resource estimates for the Hicks Dome area are beyond the scope of this work, an economic deposit of F, REEs, and/or base metals may be present at Hicks Dome and other igneous occurrences. The igneous lithotype, mineralogy, whole rock geochemistry, and regional geologic context support such a conclusion.
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Camp, Kristen F. "Mineralogy and Geochemistry of Anorogenic Granitic Miarolitic Pegmatites Associated with the White Mountain Intrusive Suite, New Hampshire." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/1363.
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Subvolcanically emplaced granitic, miarolitic pegmatites associated with the White Mountain Igneous Province (WMIP), New Hampshire, were sampled and analyzed using modern analytical techniques including X-ray fluorescence, electron microprobe, scanning electron microscopy, and direct-coupled plasma spectrophotometry. Analytical results suggest that all the sampled miarolitic pegmatites from this study are petrogenetically related to the same intrusive suite, the WMIP. Based on the geochemical data, all the samples formed in an anorogenic tectonic setting and are rift-related. They are classified as NYF-type and plot in the “within plate granite” field on tectonic discrimination diagrams. The majority of the samples are peraluminous, A1-type granites. The trace element abundances on the spider diagram and chondrite-normalized diagram, which include a pronounced negative Eu anomaly and REE enrichments, are consistent with these miarolitic pegmatites resulting from a strongly fractionated granitic parental melts, but less fractionated than the classic NYF-systems such as South Platte (Simmons et al. 1987) and the Wausau Syenite Complex (Meyers et al. 1984).
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Liu, Pingping, and 刘平平. "Petrogenesis of the Baima Fe-Ti-(V) oxide-bearing layered intrusion in the Emeishan large igneous province, SW China." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/207172.
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Zoller, Kevin M. "Porphyritic Intrusions of the Helen Zone in the Cove Deposit, Lander County, Nevada." University of Akron / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=akron1398079611.
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Brown, Connie Lynn. "The construction of a plutonic complex in a continental arc setting the Skookum Butte stock, western Montana /." CONNECT TO THIS TITLE ONLINE, 2008. http://etd.lib.umt.edu/theses/available/etd-05302008-145300/.
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Cavalheiro, Mara Lia Dias. "Levantamento gravimétrico na Jazida Carbonífera Morungava-Chico Lomã, RS." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2016. http://hdl.handle.net/10183/150209.
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A presente dissertação foi desenvolvida conforme a norma 103 do Programa de Pós Graduação em Geociências da Universidade Federal do Rio Grande do Sul, que prevê a submissão da dissertação de mestrado em forma de artigo, antecedido de estado da arte do tema proposto. Na região sudeste da Bacia do Paraná estão localizados depósitos de carvão economicamente importantes nos estados do Paraná, Santa Catarina e Rio Grande do Sul. Esses depósitos são frequentemente muito alterados por intrusões vulcânicas. O objetivo principal desse estudo é mapear essas intrusões ígneas que afetam o nível de alteração térmica do carvão (rank) da Jazida carbonífera Morungava-Chico Lomã no RS. A Jazida Morungava-Chico Lomã foi descoberta no século passado e nunca foi minerada. É caracterizada por rochas orgânicas do Permiano, carvão e folhelho betuminoso, na porção sul da Bacia do Paraná. A aquisição gravimétrica foi realizada na área do depósito Morungava e na área do depósito Chico-Lomã. Para ambas a escolha dos locais de aquisição foi baseada em furos de sondagem anteriormente realizados. Com os dados dos furos de sondagem foram elaborados seguintes mapas temáticos: profundidade da primeira ocorrência de carvão; espessura cumulativa do carvão; profundidade da primeira ocorrência de diabásio; espessura cumulativa do diabásio; espessura cumulativa do diabásio na Formação Irati e espessura cumulativa do diabásio na Formação Rio Bonito. Na elaboração do artigo submetido foi realizada a sobreposição das isolinhas das espessuras cumulativa do carvão e do diabásio nos mapas de anomalia Bouguer filtrados. Essas sobreposições apresentaram correlações e auxiliaram na interpretação dos dados gravimétricos. A orientação preferencial predominante das anomalias foi NE-SW e uma orientação subsidiária de direção NW-SE, o que sugeriu um controle estrutural sobre a ocorrência de diques e/ou soleiras, sob os altos gravimétricos. Em Chico Lomã a ocorrência de uma extensa anomalia Bouguer positiva formando um trend de orientação NE-SW foi correlacionada a unidades geológicas da Planície Costeira do Rio Grande do Sul: altos gravimétricos caracterizaram a Barreira I e baixos gravimétricos, os Sistemas Lagunares I e II. O método gravimétrico se mostrou eficaz para a caracterização da jazida por meio da correlação de anomalias gravimétricas positivas com as ocorrências de diabásio.The present dissertation was developed according to standard 103 of the Graduate Program in Geosciences of the Federal University of Rio Grande do Sul, which provides for the submission of the dissertation in the form of article, predates by state of the art proposed theme. In the southeastern region of the Paraná Basin are located economically important coal deposits in the states of Parana, Santa Catarina and Rio Grande do Sul. These deposits are often much altered by volcanic intrusions. The objective of this study is to map the igneous intrusions affecting the thermal change of level of coal (rank) of the coal deposit Morungava-Chico Lomã in RS. The coal deposit Morungava-Chico Lomã was discovered in the last century and has never been mining. It is characterized by organic rocks of the Permian, coal and bituminous shale, in the southern portion of the Paraná Basin. The gravimetric acquisition was carried in área of the deposit Morungava and in the area of the deposit Chico-Lomã. For both areas the choice of acquisition locations was based on previously conducted drilling holes. With data from the holes drilling were prepared these thematic maps: depth of the first occurrence of coal; cumulative thickness of coal; depth of the first occurrence of diabase; cumulative thickness of diabase; cumulative thickness of diabase in Irati Formation and cumulative thickness of the diabase in Rio Bonito Formation. In the elaboration of article submitted the overriding of the isolines of cumulative thickness of coal and diabase in the filtered Bouguer anomaly maps was performed. These overrides presented correlations and assisted in the interpretation of gravity data. The predominant preferential orientation of the anomalies was NE-SW and a subsidiary orientation NW-SE direction, suggesting a structural control on the occurrence of dikes and/or sills, on gravimetric high. In Chico Lomã the occurrence of an extensive positive Bouguer anomaly forming a trend of NE-SW orientation was correlated with geological units of Rio Grande do Sul Coastal Plain: gravimetric characterized the high Barrier I and low gravimetric, Systems Lagunar I and II. The gravimetric method proved efficient for the characterization of the deposit through the correlation of positive gravity anomalies with occurrences of diabase.
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Wilson, Penelope Irene Rose. "Direct linking of host rock deformation structures to the emplacement, morphology and accommodation of high-level igneous intrusions : the Henry Mountains, Utah." Thesis, Kingston University, 2015. http://eprints.kingston.ac.uk/34543/.
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Most studies of magmatic intrusions concentrate on geometry and internal architecture: only a few pay particular attention to emplacement-related deformation structures in the host rock that record how magma is accommodated within the crust. This research aims to develop a greater understanding of how igneous intrusive bodies are emplaced and accommodated within the shallow crust, using classic exposures found in the Henry Mountains, Utah. Two satellite intrusions to the Mt Hillers intrusive centre show highly contrasting geometries, host-rock deformation and accommodation structures and apparent emplacement mechanisms. Trachyte Mesa, the most distal satellite intrusion of Mt Hillers, has a relatively simple elongate (NW-SE) geometry, concordant with the Entrada Sandstone it intrudes. The intrusion is comprised of multiple, stacked intrusive sheets. Syn-emplacement deformation structures observed in the host rocks consist of a conjugate set of intrusion margin-parallel deformation bands and extensional brittle faults, the latter occurring at the tips of intrusive sheets. These structures, along with a post¬emplacement set of intrusion margin parallel and perpendicular tensile joints, indicate extensional strain normal to the intrusion margin, consistent with a two-stage growth mechanism for individual sheets as well as the overall intrusion. In comparison, Maiden Creek shows a more complex intrusion geometry, including: lobate morphologies; steps and broken bridges; inclined sill sheets; and concave-upwards 'Iaccolithic' morphologies. A new model is proposed for the emplacement, evolution and final geometry of the intrusion, with a central elongate NE-SW lobe resulting from a principal north-easterly propagating magma flow. Lateral growth of the Maiden Creek intrusion resulted from radial spreading of magma from this main north-easterly flow trend towards the east and north-west. It is proposed that the southern Maiden Creek intrusion is comprised of two westerly-derived (saucer-shaped?) sills. Overlying these deeper-rooted sills is the newly identified Maiden Creek Shear Zone (MCSZ). This structure is an antithetic accommodation structure to magma flow. Substantial amounts of strain observed through microstructural analysis of shear zone samples suggest that the MCSZ played a critical role in accommodating magma emplacement. This study suggests that much can be learnt about intrusion geometries and emplacement mechanisms through detailed structural and kinematic analyses of the host rocks and intrusion-host rock contact.
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Gallagher, Brookie Jean. "A Comparative Study of the Badger Pass Igneous Intrusion and the Foreland Volcanic Rocks of the McDowell Springs Area, Beaverhead County, Montana: Implications for the Local Late Cretaceous Sequence of Events." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/geosciences_theses/11.
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Intermediate igneous rocks exposed in the Badger Pass area and 3.5 km away in the McDowell Springs area of Beaverhead County, Montana, previously mapped as Cretaceous intrusive (Ki), and Cretaceous undifferentiated volcanics (Kvu) respectively, exhibit little geochemical variation. Trace element, and lead isotope analyses provide strong evidence allowing for a single source. REE patterns, obtained through ID-ICP-MS, are essentially identical. Mineral/melt Eu analyses reveal that Eu behaved predominantly as a divalent cation, refuting an earlier study asserting that trivalent Eu dominated. Data suggest rocks were formed under low oxygen activity conditions, not oxidizing conditions as previously reported. Geochemical data combined with field mapping allow us to establish the temporal relationship between late Cretaceous thrusting, intrusion, and volcanism in this locale. Folding, faulting and thrusting were significantly, if not entirely, completed prior to the commencement of volcanism. Volcanism included contemporaneous thrust plate intrusion, foreland extrusion, and hypabyssal foreland intrusion.
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Hansen, Jógvan. "Petrogenetic evolution, geometries and intrusive styles of the early Cenozoic saucer-shaped sills of the Faroe Islands." Thesis, Durham University, 2011. http://etheses.dur.ac.uk/3631/.
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Geometries of sills intruded into the lava pile of the Faroe Island Basalt Group (FIBG), which were targeted in this study, were mostly recorded by conventional mapping methods where measured distances and positions were plotted onto accurate topographic maps aided by the use of high-quality photos of relevant outcrops. These data were subsequently used to manually plot 2D profiles along selected tracks and to produce electronic 3D maps using ArcGIS software. The general geometries of the investigated sills, measured at lateral scales ranging from a few metres to a few kilometres and at vertical scales ranging from a few metres to a few hundred metres, differ somewhat from typical sill geometries reported previously for sills intruded into sedimentary successions. The ubiquitous saucer-shapes of the sills from this study, which generally curve upwards in a gradual manner from inner sub-horizontal sections to steeper outer margins, contrast with the common angular transitions from inner sub-horizontal to outer steeper sections of sills reported from sedimentary host-rocks. In this thesis we explore possible alternatives to already existing theories on sill emplacement in sedimentary successions. Major and trace element compositions for samples representing most of the sills exposed in the Faroe Islands have been determined by means of XRF and ICP-MS analyses. Geochemically most of these sills can be grouped into two main categories characterised either by high or by low TiO2 contents. Different sorts/types of metasomatism of source rocks to high-TiO2 versus low-TiO2 sills are indicated by different Nb and Ta anomalies. Modelling by means of REE and other trace elements suggest that much of the compositional differences between these two main categories can be explained by various degrees of partial melting of broadly similar mantle sources. Additional fractionation and accumulation of plagioclase modified some of the melts that gave rise to the actual sills. The initial partial melting event probably occurred at depths slightly shallower than the lower limit of the garnet stability field at ~85 km while plagioclase crystallisation/accumulation most likely occurred at depths shallower than ~18 km. Isotopic compositions may point to very slight contamination of some sills with crustal material.
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Suarez, Tatiana Arenas. "Resfriamento de corpos intrusivos no interior da crosta continental: o efeito da liberação do calor latente." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/14/14132/tde-02072018-164306/.
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O presente trabalho tem como objetivo estudar a evolução térmica de corpos intrusivos em diferentes níveis da crosta formados por múltiplas injeções de magma em forma de sils, levando em consideração mudança de fase e liberação de calor latente em um intervalo finito de temperaturas. A análise proposta inclui o estudo dos modelos de transferência de calor puramente condutivos utilizando a equação da evolução da entalpia que integra a mudança composicional dos magmas. A evolução térmica do corpo ígneo gerado por introdução do magma basáltico através de sils na crosta inferior obtém-se usando o método das diferenças finitas em uma dimensão, além disso se desenvolvem duas formas de construção do corpo ígneo neste nível: acréscimo por cima e acréscimo por baixo, sendo o primeiro caso o mais eficiente em manter o sistema a temperaturas elevadas durante mais tempo. Na crosta superior a evolução térmica do corpo ígneo de composição próxima ao tonalito introduzido por meio de sils é resolvida em duas dimensões com o método dos elementos finitos utilizando uma geometria com simetria axial no eixo z. O desenvolvimento destes corpos depende do ritmo de acréscimo do magma e das propriedades térmicas tanto da crosta como do magma injetado, podendo desenvolver-se como uma câmara magmática, um repositório de fusão ou um corpo altamente cristalino. A segunda fase do trabalho consistiu na solução da equação de condução de calor com mudança de estado em câmaras magmáticas esféricas, esferóides oblatos e esferóides prolatos com o método de elementos finitos para analisar evolução do sistema crosta-câmara magmática e introduzir o estudo da variação da viscosidade em função da temperatura. A geometria da câmara magmática influencia fortemente os fluxos de calor à crosta e portanto a criação de um halo dúctil que pode afetar a estabilidade dela mesma.The purpose of this work is to study the thermal evolution of intrusive bodies formed by successive sills injection in different levels of the crust, taking into account the phase change and latent heat release in a finite temperatures interval. Our numerical models involve heat transfer only by conduction. Thermal evolution of the system is found with the energy balance equation of enthalpy that includes phase and composition change of magmas. The thermal evolution of the basaltic igneus body intruded into the lower crust is evaluated using finite difference scheme. At this level of the crust we develop two different ways of igneus body construction: over- accretion and under-accretion. Over-accretion is the more efficient way for keeping high temperatures in the time. In the upper crust, the thermal evolution of a tonalite igneus body formed by successive sils injection is computed with finite elements method in a geometry with rotational symmetry about z axis. Thermal and geological development of this igneus bodys strongly depends on magma emplacement rate and magma and crust thermal proprerties. These features defines if the igneus body develops in a magmatic chamber, a melt reservior or a high crystalline body. In the second part of this work we examine heat transfere from magamatic chambers of different geometries into the country rock, solving the entalphy equation with latent heat release effects with finite element method. The magmatic chambers geometries constructed are oblate spheroid, prolate spheroid and spherical. The viscosity of the rock is also obteined from temperature field.
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Schucker, Dennis Eugene. "Mesozoic igneous intrusions in New England and Quèbec : implications from lead (Pb) isotopes on petrogenesis and mantle sources (Ascutney Mountain, VT; Mont Saint Hilaire, Quèbec; Pliny Complex, NH) /." The Ohio State University, 1992. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487779120909591.
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Oliveira, Eduardo Barreto. "Geração não convencional de hidocarbonetos na região carbonífera de Santa Catarina." Universidade do Estado do Rio de Janeiro, 2009. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=1105.
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Agência Nacional do PetróleoNa região de Lauro Müller, sul de Santa Catarina, a presença de óleo nos arenitos das formações Rio Bonito e Palermo foi observada em diversos poços e nas galerias de uma das minas da Carbonífera Catarinense. Amostras desse óleo foram submetidas às análises de isótopos estáveis de carbono e cromatografia gasosa espectrometria de massas visando, a princípio, identificar a sua origem. O óleo apresentou feições moleculares típicas de ambiente anóxico hipersalino, sendo correlacionado ao Membro Assistência da Formação Irati. Parâmetros moleculares revelaram que o mesmo foi gerado durante o pico de geração de hidrocarbonetos e encontra-se leve a moderadamente biodegradado. A comparação entre o óleo catarinense e os arenitos asfálticos de Anhembi (SP) revelou diferenças moleculares relacionadas à fácies orgânica, grau de evolução térmica e biodegradação. A geração do óleo no sul catarinense está intimamente relacionada ao efeito térmico das intrusões ígneas cretácicas sobre os intervalos geradores da Formação Irati, haja vista que a unidade encontra-se termicamente imatura na maior parte da bacia. O óleo teria migrado lateralmente da Formação Irati para os arenitos reservatório da Formação Rio Bonito através de falhas com rejeitos verticais superiores a 150 m, as quais foram identificadas em mapas e seções geológicas. Também foram realizadas análises de pirólise, isótopos de carbono e de biomarcadores em amostras da Formação Irati no poço CAT 204, realizado pela Carbonífera Catarinense, a fim de avaliar o efeito térmico de duas soleiras de diabásio intrudidas no Membro Assistência. Foi observado um aumento dos valores de δ13C em direção ao contato com as intrusivas e a completa senilização da unidade. O halo termal abaixo da soleira inferior se estendeu, pelo menos, até a base da Formação Irati, situada a uma distância de 1,4 vezes a espessura do corpo intrusivo. Amostras da parte inferior da Formação Palermo, coletadas no poço CAT 204, e das três principais camadas de carvão do sul catarinense, coletadas nas minas da Carbonífera Catarinense, também se encontram termicamente maturas, sugerindo a proximidade de outros corpos intrusivos. Dessa forma, conclui-se que deve ter havido um aquecimento generalizado dos sedimentos no sul de Santa Catarina causado pela grande incidência de soleiras na região.
In the region of Lauro Müller, south of Santa Catarina, the presence of oil in sandstones of Rio Bonito and Palermo formations were observed in several wells and in the galleries of a coal mine. Samples of oil were subjected to stable carbon isotopes and gas chromatography mass spectrometry analysis to identify its origin. The oil had typical features of a hypersaline anoxic environment, achieving a positive correlation with Assistência Member of Irati Formation. Molecular parameters revealed that it was generated during the peak of hydrocarbon generation and is light to moderately biodegraded. The comparison between oil encountered in Lauro Müller and the tar sands of Anhembi (SP) revealed molecular differences related to organic facies, level of biodegradation and thermal maturity. The generation of oil in southern Santa Catarina is closely related to the thermal effect of igneous intrusions in the source rocks of Irati formation, given that the unit is thermally immature in most of the basin. The oil would have migrated laterally from Irati Formation to the reservoir sandstones of Rio Bonito Formation through faults with vertical slips over 150 m, identified on maps and geological sections. Pyrolysis, stable carbons isotopes and biomarkers analysis was also performed in a local section of Irati Formation to evaluate the heating effect of two dolerite sills intruded into Assistência Member. It was observed an increase in δ13C toward the intrusive contacts and that Assistência Member was completely overmature. The thermal halo below the lower sill reached, at least, the bottom of the Irati Formation, located at a distance of 1.4 times the thickness of the intrusive body. Samples from the lower portion of Palermo Formation, collected in the well CAT 204, and the three main coal layers from southern Santa Catarina, collected in Carbonífera Catarinenses mines, are also thermally mature, suggesting the proximity of other intrusive bodies. Thus, it is concluded that there was a general heating of the sediments of southern Santa Catarina caused by the high incidence of igneous intrusions in the region.
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Howarth, Geoffrey Hamilton. "Petrogenesis and metallogenesis of the Panzhihua Fe-Ti oxide ore-bearing mafic layered intrusion, SW China." Thesis, Rhodes University, 2013. http://hdl.handle.net/10962/d1001810.
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The Panzhihua intrusion is one of several large Fe-Ti oxide ore bearing intrusions related to the major flood volcanism of the Emeishan Large Igneous Province (ELIP), SW China. The Panzhihua intrusion in particular has recently become the focus of numerous studies owing to the excellent exposure in large open pit mining operations. The formation of Fe-Ti oxide ore layers has been the focus of these studies and has become a somewhat controversial topic with three separate models currently proposed for ore formation. The gabbroic Panzhihua intrusion extends for ± 19 km along strike, has a maximum thickness of 3000 m and hosts extensive (up to 60 m thick) Fe-Ti oxide ore layers in the lower portions of the intrusion. The intrusion has been divided into five zones: marginal zone (MGZ), lower zone (LZ), middle zone A (MZa), middle zone b (MZb) and the upper zone (UZ). The gabbroic rocks are comprised of plagioclase, clinopyroxene and interstitial Fe-Ti oxides with minor olivine. Apatite is present within the MZb only and shows no correlation with Fe-Ti oxide ore layers. Fe-Ti oxides are present throughout the stratigraphy of the intrusion. This is unlike typical layered intrusions where significant Fe-enrichment through fractionation of Fe-poor silicate phases (i.e. plagioclase) is required before Fe-Ti oxide saturation. There are no oxide-free cumulate rocks at the Panzhihua intrusion, implying either an evolved parent magma or very high Fe content of the source rocks. I present here new mineral composition data, whole-rock major and trace element geochemistry along with whole-rock Sr-Nd isotopes and PGEs in order to constrain the evolution of the Panzhihua parent magma en route from source to chamber and the formation of Fe-Ti oxide ore layers. Furthermore an initial pilot study using O-isotope data is conducted on Ti-magnetite and plagioclase separates from gabbroic vs. ore rocks. Results are coupled with detailed thermodynamic modeling using the software PELE in order to further constrain Fe-Ti oxide ore layer formation. The intrusion is characterised by extreme depletion of PGEs relative to the coeval flood basalts and picrites. High Cu/Pd and Pd/Pt imply two separate stages of S-saturated and S-undersaturated depletion of PGEs. Pd is highly compatible in sulphide and is quickly scavenged by sulphide liquids resulting in an increase in Cu/Pd of the residual liquid. Furthermore decoupling of Pd and Pt can be achieved by either late stage hydrothermal alteration or through S-undersaturated stage of PGE depletion where Pt is scavenged by Pt-rich alloys or oxide minerals. I show that the latter is more likely. Fractionation modeling suggests that the Panzhihua parent magma formed at depth from original picritic magma. This is consistent with several other recent studies on other layered intrusions of the ELIP. Sr-Nd isotopic ratios indicate very little crustal contamination has occurred en route to the current chamber. Sr and Nd concentrations of footwall rocks are too low to produce any significant change in initial Sr and Nd isotopic ratios of the intruding basaltic magmas, indicating that crustal contamination will not be indicated by Sr-Nd isotopic ratios. Gradational change in the Sr-Nd isotope ratios across the MGZ provides strong evidence for formation in an open system by multiple replenishments of progressively less contaminated magmas from depth. Contamination is difficult to constrain but must be occurring prior to emplacement at the current level (low Sr and Nd contents of footwall). A gradational upward decrease in highly incompatible element across the MGZ can then be explained by continuous magma flow, which effectively removes the evolved intercumulus liquids from the growing cumulate pile at the base of the chamber. The initial stages of formation of the Panzhihua intrusion are interpreted to result from prolonged low volume pulses of magma into a slowly opening chamber. The timing of Fe-Ti oxide crystallisation is fundamental in the understanding of the petrogenesis of ore layers. Distinct geochemical variation in whole-rock Fe2O3/TiO2 and Zr/Nb indicates that Timagnetite is the dominant oxide within the lower ± 270 m of the intrusion whereas above this level both Ti-magnetite and ilmenite are present as cumulus phases. This is interpreted to indicate a variation in the fO2 where the lower intrusion crystallises at higher fO2 relative to that above this level. Silicates within the ore layers, in particular plagioclase, are highly embayed and resorped where in contact with Fe-Ti oxides. This characteristic of the silicate grains implies early crystallisation prior to Fe-Ti oxides with subsequent disequilibrium conditions resulting in resorption. Furthermore distinct reaction rims of kaersutite amphibole, Fo-enriched olivine, An-enriched plagioclase and pleonaste are observed. The abundance of amphibole suggests H2O involvement in this reaction and consumption of silicates. A model for parent magma crystallisation at various H2O contents indicates that plagioclase crystallisation temperature is very sensitive to H2O content of the parent magma. Plagioclase crystallises early for “dry” compositions but significantly later for “wet” compositions. Fe-Ti oxide ore layers are generally well layered, contain gabbroic xenoliths and are observed raversing/cross-cutting the cumulate stratigraphy. I present here a new model for ore layer formation in order to account for these distinct features of the ore layers. A model invoking multiple replenishments of magma with variable oxide microphenocryst content, H2O content and volume is proposed. Magma evolving in the plumbing system and fed to the Panzhihua chamber is variably enriched in H2O, which results in significantly different crystallisation paths. High H2O magmas (> 2 wt %) crystallise Fe-Ti oxides early whereas low H2O magmas (< 1 wt %) crystallise oxides late. Early pulses of H2O-poor magma crystallise a sequence of plag+cpx+Fe-Ti oxide (±ol). Later pulses of H2Orich magma subsequently intrude the partially crystallised cumulate sequence incorporating and consuming previously crystallised silicates with subsequent early crystallisation of Ti-magnetite and formation of ore layers. H2O-rich magmas likely have suspended Ti-magnetite microphenocrysts as well, which crystallise at depth in the plumbing system. This model can account for the various characteristic features of the Fe-Ti oxide ore layers at the Panzhihua intrusion as well as other Fe-Ti oxide ore bearing intrusions in the region.
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Corrêa, Luís Maurício Salgado Alves. "Avaliação do efeito térmico das soleiras de diabásio nas rochas geradoras da formação Irati (Bacia do Paraná, Brasil) através de técnicas de modelagem numérica." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=322.
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Coordenação de Aperfeiçoamento de Pessoal de Nível SuperiorNa avaliação da maturidade de horizontes geradores e da história térmica de uma bacia com registro de atividade magmática é preciso considerar o efeito térmico imposto pela intrusão de corpos ígneos, como diques e soleiras. Dessa maneira, foi realizada a análise numérica transiente, pelo método de diferenças finitas, do fluxo térmico por condução provocado pela intrusão das soleiras básicas cretáceas nos horizontes geradores do Membro Assistência, Formação Irati, Bacia do Paraná. Esta análise, por sua vez, viabilizou a modelagem do parâmetro de reflectância da vitrinita nos estratos de folhelhos adjacentes às soleiras. Para tanto, foram utilizados os dados de seção de três poços, os quais registram espessuras de soleiras de até 4 m, e um poço com uma soleira de 27 m de espessura. Os poços localizam-se na porção sudeste da bacia. Na simulação numérica, foi considerado o processo de solidificação do magma ou de cristalização das suas fases minerais. A modelagem de reflectância da vitrinita baseou-se em um modelo pré-concebido da história térmica da Formação Irati, sendo os resultados desta simulação de maturidade do querogênio obtidos através do uso do programa EASY%Ro. Considerando-se os erros embutidos no modelo numérico e na discretização da história térmica dos estratos estudados, foram obtidos valores modelados de reflectância da vitrinita similares aos valores medidos nos poços pelo método tradicional. Somente no caso da seção com a soleira de 27 m de espessura houve uma grande diferença entre estes valores. Contudo, o alto coeficiente de correlação (0,95) entre estes possibilita a correção do efeito da espessura da soleira em análises futuras. Assim, a análise numérica simulou o halo térmico da soleira, caracterizado, segundo os dados de modelagem de refletância da vitrinita, por uma faixa acima e abaixo da soleira com espessura equivalente à espessura da soleira encaixada nos estratos geradores da Formação Irati. Essa metodologia de avaliação propicia um estudo preditivo das condições de maturidade de horizontes geradores em bacias ou áreas com magmatismo intrusivo, nas quais as análises do parâmetro de reflectância da vitrinita sejam ausentes ou escassas.
To evaluate the thermal maturity and thermal history of source rocks in basins with magmatic activity it is important to consider the thermal effects imposed by igneous intrusions, such as sills and dykes. This work uses the finite difference method for such evaluation, with the transient numerical analysis of heat conduction from Cretaceous diabase sills intruded into the source rocks of the Assistência Member, Irati Formation, Paraná Basin. This analysis has permitted modeling vitrinite reflectance of the shale strata adjacent to the sills. The data of four wells are used from the southeastern portion of the basin, with diabase thicknesses, respectively, of 1m, 2 m, 4 m and 27 m. The numerical simulation includes the process of magma solidification or mineral phase crystallization. The vitrinite reflectance modeling followed a pre-established thermal history of the Irati Formation, using the EASY%Ro program to simulate kerogen maturity levels. Considering the errors built into the numerical model and the thermal history discretisation of studied strata, the acquired values of modeled vitrinite reflectance closely resembled well data analyzed by the traditional method. Major discrepancies were observed in the case of the well containing a sill 27 m thick, but even in this case the high correlation coefficient (0,95) between the measured and calculated values is expected to permit correction of the sill thickness effect in future studies. The numerical analysis correctly simulated the thermal halo induced by sill emplacement, enabling vitrinite reflectance modeling to characterize it as a zone extending both above and below the sill with thicknesses similar to that of the sills. This evaluation methodology contributes to a predictive study of the maturity conditions of source rocks within basins or areas with intrusive magmatism where analysis of the vitrinite reflectance parameter are sporadic or absent.
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Bouabsa, Lakhdar. "Intrusions granitiques à albite et topaze : Minéralisations stanno-wolframifères et altérations hydrothermales associées, l'exemple du hoggar central, Algérie." Nancy 1, 1987. http://www.theses.fr/1987NAN10329.
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Le présent travail met l'accent sur la dualité du magmatisme de cette région du Hoggar Central. Outre un granite banal à biotite (parfois amphibole) constituant l'ossature principale des granites post orogéniques (Taourirts), il est mis en évidence un type particulier de granite spécialisé à albite, topaze et protolithionite comme paragénèse I. Ce magmatisme évolué est sans liaison génétique avec le précèdent comme le soulignent les contacts intrusifs marqués par des stockscheiders et les discontinuités géochimiques au niveau des éléments majeurs et tracés. La liaison spatiale et génétique des altérations hydrothermales avec ce magmatisme spécialisé apparait évidente. Ces altérations affectent les différents termes magmatiques de la région ; Elles sont essentiellement lithinifères, fluorées (protolithionite, muscovité lithinifère, topaze et fluorine) et peuvent conduire à des phénomènes de convergence à partir des granites banaux à biotite. Les minéralisations SN-W, déjo exprimées de façon primaire dans les granites à albite - topaze, sont liées au développement de ces altérations greisénisantes fissurales
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Laporte, Didier. "Un exemple d'intrusion syntectonique : l'intrusion d'Ile-Rousse, Corse du nord-ouest : étude pétrographique, minéralogique et géochimique, analyse structurale." Saint-Etienne, 1987. http://www.theses.fr/1987STET4001.
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L'intrusion d'Ile Rousse est une association intime de granitoïdes aux caractéristiques plus ou moins fortement contrastées, juxtaposés en lames subméridiennes à fort pendage. On y distingue des granitoïdes calcoalcalins magnésio-potassiques et des granitoïdes n'appartenant pas à l'association magnésiopotassiques dont les mieux types sont les granodivrités de Corbara. Analyse statistique de la sous-fabrique des mégacristaux de Feldspath potassique accompagnée d'une modélisation mathématique
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Barra-Pantoja, Luis Fernando. "A Re-Os Study of Sulfides from the Bagdad Porphyry Cu-Mo Deposit, Northern Arizona, USA." Thesis, The University of Arizona, 2001. http://hdl.handle.net/10150/249252.
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Use of Re-Os systematics in sulfides from the Bagdad porphyry Cu-Mo deposit provide information on the timing of mineralization and the source of the ore -forming elements. Analyzed samples of pyrite, chalcopyrite and molybdenite mainly from the quartz monzonite and porphyritic quartz monzonite units are characterized by a moderate to strong potassic alteration (secondary biotite and K- feldspar). Rhenium concentrations in molybdenite are between 330 and 730 ppm. Two molybdenite samples from the quartz monzonite and porphyritic quartz monzonite provide a Re-Os isotope age of 71.7 ± 0.3 Ma. A third sample from a molybdenite vein in Precambrian rocks yields an age of 75.8 ± 0.4 Ma. These molybdenite ages support previous suggestions of two mineralization episodes in the Bagdad deposit. An early event at 76 Ma and a later episode at 72 Ma. Pyrite Os and Re concentrations range between 0.008-0.016 and 3.9-6.8 ppb, respectively. Chalcopyrite contains a wide range of Os (6 to 91 ppt) and Re (1.7 to 69 ppb) concentrations and variable ¹⁸⁷Os/¹⁸⁸Os ratios that range between 0.13 to 22.27. This variability in the chalcopyrite data may be attributed to different copper sources, one of them the Proterozoic volcanic massive sulfides in the district, or to alteration and remobilization of Re and Os. Analyses from two pyrite samples yield an eight point isochron with an age of 77 ± 15 Ma and an initial ¹⁸⁷Os/¹⁸⁸Os ratio of 2.12. This pyrite Re-Os isochron age is in good agreement with the molybdenite ages. We interpret the highly radiogenic initial 1870s/188Os as an indication that the source of Os and, by inference, the ore-forming elements for the Bagdad deposit, was mainly the crust. This conclusion agrees with previous Pb and Nd isotope studies and supports the notion that a significant part of the metals and magmas have a crustal source.
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Costarella, René. "Le complexe annulaire alcalin de Combeynot ( Massifs cristallins externes, Alpes françaises), témoin d'un magmatisme en régime distensif. Pétrogéochimie et signification géodynamique." Phd thesis, Grenoble 1, 1987. http://tel.archives-ouvertes.fr/tel-00539879.
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Le massif de Combeynot, sur la bordure nord-orientale du massif du Haut-Dauphiné (massifs cristallins externes, Alpes Françaises) est constitué de deux unités fondamentales (1) un socle, déformé et métamorphisé, représenté par un ensemble migmatitique et un orthogneiss oeillé ; ce socle se rattache aux formations du noyau du massif du Haut-Dauphiné, (2) un complexe annulaire subvolcanique, intrusif dans le socle, composé de formations volcaniques et volcano-détritiques, d'un réseau filonien microgranitique et rhyolitique très dense, de deux unités granitiques disposées de manière concentrique et de filons doléritiques tardifs terminant l'épisode magmatique. Une étude comparative sur la pétrographie, la structure, la typologie des zircons et la géochimie des éléments majeurs, en traces (Y, Nb, Zr, Rb, Sr, U, Th, Hf, Sc, Cs et Ta) et Terres Rares du complexe de Combeynot ont permis de retracer l'histoire magmatique de la série et de tester sa signification géodynamique. Le magmatisme de Combeynot est de nature alcaline intraplaque et traduit un environnement géotectonique de distension. Il trouve son origine dans le manteau à partir duquel plusieurs magmas subcontemporains s'individualisent par des taux de fusion partielle différents et conduisent aux unités acides par cristallisation fractionnée. Leur mise en place superficielle dans une zone orogénique encore non consolidée, riche en fluides et la participation des phases fluides juvéniles et/ou des eaux météoriques conditionnent la nature pétrographique acide, sursaturée et subsolvus des unités granitiques du complexe ainsi que les processus d'altération hydrothermale post- et tardi- magmatiques.
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Fumerton, Stewart Lloyd. "The felsic intrusives In E.R.P.M., Boksburg." Thesis, 2015. http://hdl.handle.net/10539/17282.
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Scogings, Andrew John. "Alkaline intrusives from the Tugela terrane, Natal metamorphic province." Thesis, 1991. http://hdl.handle.net/10413/11162.
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Three gneissose alkaline granitoid intrusives at Ngoye, Bulls Run and
Wangu are described. They are located within the Nkomo Nappe of the
Tugela Terrane, near the northern margin of the Natal Metamorphic
Province.
The Ngoye Complex comprises alkaline granites, with minor syenite and
monzodiorite phases. According to modal am geochemical criteria the
Ngoye granites range from peraluminous (muscovite-bearing), through
metaluminous (biotite- and/or hornblende-bearing), to peralkaline
(riebeckite-, aegirine- and magnetite-bearing). The granites are
A-types according to their modal and geochemical characteristics. Rb-Sr
isotopic data for the hornblende granites indicate an age of 1063 ± 17
Ma and the initial ratio (R๐ = 0.7025) provides evidence for
derivation from a mantle source. Plotting of the Ngoye geochemistry on
tectonic-discrimination diagrams suggests intrusion into rifted
continental crust. It is concluded that the gneissose Ngoye granites
constitute a deformed central complex, similar to anorogenic complexes
in Nigeria and the Sudan.
The Bulls Run Complex is situated 30 km west of the Ngoye Complex. A
concentric outcrop pattern has been mapped, according to which an
envelope of silica-saturated biotite-muscovite syenite surrounds a core
of nepheline-bearing syenites. Minor intrusive phases include
biotite-rich dykes, sovite carbonatite sheets, silica-oversaturated
microsyenite dykes and feldspathic ijolite. The outer envelope of
muscovite-rich syenite is interpreted as fenitised pelitic country
rock. An alkali-lamprophyre origin is suggested for the biotite-rich
dykes. Geochemically the syenites are predominantly miaskitic, apart
from the microsyenite dykes which are mildly peralkaline. Rb-Sr
isotopic data for the nepheline syenites indicate an age of 1138 ± 45 Ma
(Ro = 0.70322). Carbonate separates from the carbonatites provide a
similar low initial ratio (Ra = 0.70319) which supports a comagmatic
mantle origin. A comparison is drawn between the Bulls Run Complex and
miaskitic nepheline syenite gneisses in the mid-Proterozoic Grenville
Province of canada. From this, it is suggested that the Bulls Run
Complex is pretectonic and was intruded into the rifted passive margin
of a continent.
The Wangu Granite Gneiss is situated 3 km southwest of the Bulls Run
Complex. The granites are fine grained and contain aegirine-augite
and/or magnetite, and classify as alkali-feldspar granite. Peralkaline
chemistry is characteristic of the Wangu granites, with trace-elenent
contents indicating a distinct A-type signature. Biotite-rich mafic
dykes intrude the southern part of the Wangu outcrop and, on the basis
of major- and trace-element signatures, are suggested to be
metamorphosed volatile-rich alkaline lamprophyres similar to those at
Bulls Run. Geochemical similarities between the Wangu granites and
certain comendites from the Kenya Rift are noted. It is suggested that
the Wangu granites were emplaced as high-level dykes, within rifted
continental crust.
It is proposed that the Ngoye, Bulls Run and Wangu intrusives be united
as the Nkwaleni Suite.
Comparison of the Tugela Terrane with the Grenville Province reveals
many similarities, particularly their mid- to late-Proterozoic age and
the occurrence of pre-tectonic anorogenic continental magmatism. It is
concluded that, unlike the current model which would have the Tugela
Terrane as obducted ophiolite, these new data indicate that the Tugela
Terrane is a metamorphosed continental rift system.Thesis (Ph.D.)-University of Durban-Westville, 1991.
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Kimpton, B. J. "The geological relationship between Kanmantoo Cu-Au deposit mineralisation, hydrothermal metasomatism and igneous intrusives." Thesis, 2018. http://hdl.handle.net/2440/130628.
Full textAbstract:
This item is only available electronically.The Kanmantoo Cu-Au deposit has been in episodic operation since 1846, one decade after the capital city of Adelaide was established some 40 kilometres to the NW. Regionally and within the host stratigraphy there exists archetypal evidence of the Cambrian Delamerian Orogeny through a complex structural, metamorphic and intrusive history. Consequently, numerous theories exist within the literature regarding a syngenetic or epigenetic style of mineralisation and the debated contribution, if any, of magmatic hydrothermal fluids. This study has documented numerous felsic intrusive vein sets within the Kanmantoo Cu-Au deposit which have been utilised to constrain the role of igneous activity on mineralisation within a wider Delamerian context. Monazite U–Pb ages of felsic veins show that intrusion first occurred at syn-peak metamorphic, syn-orogenic conditions (495.11 ± 2.79 Ma), continuing periodically until post-peak metamorphic, extensional conditions (483.43 ± 2.52 Ma). Intrusions are coeval with mineralisation and are temporally and geochemically analogous to magmatic activity in the adjacent Monarto and Murray Bridge provinces. Analysis of trace elements in monazites identifies the Kanmantoo Cu-Au deposit as a syn- to post-peak metamorphic hydrothermal anomaly which, combined with the presence of felsic veins, indicates that mineralisation resulted partly from fluids generated by a pluton at depth. These findings broadly confirm the prospectivity of Delamerian-affected terranes throughout large parts of South Eastern Australia where pervasive intrusive geology exists.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2018
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Maes, Stephanie M. "Magnetic fabric constraints on the emplacement of igneous intrusions." 2006. http://www.library.wisc.edu/databases/connect/dissertations.html.
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Brandt, R. T. "The Geology Of Certain Igneous Intrusive Rocks In The Far East Rand, Transvaal, South Africa." Thesis, 2015. http://hdl.handle.net/10539/16428.
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Morrison, Robert Sinclair. "Igneous intrusive rocks of the peake and denison ranges within the Adelaide geosyncline / Robert Sinclair Morrison." 1989. http://hdl.handle.net/2440/18901.
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2v - 3 MicroficheTitle page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1989
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Rahilly, Kristen Elizabeth. "The Forsterite-Anorthite-Albite system at 5 kb pressure." 2010. http://hdl.handle.net/10090/15194.
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Christodoulou, C. (Constaninos). "Petrology of the plutonic rocks of the Macquarie Island Complex / C. Christodoulou." 1990. http://hdl.handle.net/2440/19657.
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Maps on 2 folded leaves in pocketIncludes bibliography (25 leaves)
ca 400 leaves in various foliations : ill. (some col.), maps ; 31 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, Dept. of Geology and Geophysics, 1992
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Chan, Christine F. "Constructing a sheeted magmatic complex within the lower arc crust : insights from the Tenpeak pluton, North Cascades, Washington." Thesis, 2012. http://hdl.handle.net/1957/36070.
Full textAbstract:
The sheeted complex of the ~92 Ma Tenpeak pluton, in the Northern Washington Cascades crystalline core, forms a <1.5-km wide zone with a moderate, NE-dip at the SW margin of the pluton. Sheeted magmatic complexes, such as the one in the Tenpeak pluton, are common in plutons and represent examples of incremental growth of plutons. Though it is widely accepted that plutons are constructed incrementally over prolonged timescales of several million years, it is not clear if and to what degree individual batches of magma interact, the timing and size of each magma pulse, and the role, timing, and location of magmatic differentiation.
This project uses a combination of field evidence, bulk rock chemistry, and mineral geochemistry to address the (1) role of magma mixing and fractionation, (2) constraints on the relative timing of magma differentiation, (3) diversity of mixing styles
preserved, and (4) physical properties that dictate how individual batches of magma interact within this sheeted complex. Rock samples were collected throughout the complex from mafic, felsic, dioritic, thinly-banded, and gradational sheets. Field evidence shows a range of sheet contacts that vary from sharp to diffuse, strong prevalence of mafic enclaves, and localized cases of mechanical mixing in which plagioclase feldspars from a felsic sheet are incorporated into a mafic sheet. In general, sheet thickness increases farther from the contact with the White River shear zone.
The bulk rock and mineral chemistry suggests that the felsic magmas in sheets formed independently from the more mafic and hybridized sheets. The composition of the felsic sheets cannot be modeling by binary mixing processes involving mafic and felsic magmas or result from fractionating the most mafic magmas. However, mass-balance calculations using a linear least-squares mass balance calculation and Rayleigh fractionation models indicate that it is possible to explain the range of felsic compositions by internal, crystal fractionation driven mostly by plagioclase crystallization (~40-58%). Negative Eu anomalies in amphiboles from the felsic sheets imply that plagioclase fractionation commenced prior to the onset of amphibole crystallization.
With the exception of the most primitive mafic sheet sampled, the mafic and hybridized sheets represent variable proportions of the mafic parental magma and the range of felsic differentiated magmas. Efficient mixing that resulted in these mafic to hybridized magmas must also have occurred prior to mineral growth as the mineral chemistry reflects intermediate, mixed compositions. The bulk rock and mineral chemistry of the most primitive, mafic sheet suggest that it did not mix with any felsic magmas. However there is evidence that the mafic sheet underwent plagioclase fractionation prior to emplacement. This is evident by lower bulk rock Sr/Ba relative to calculated Sr/Bamelt of plagioclase that cannot be reconciled without removing ~40-58% plagioclase. In contrast to the felsic sheets, the amphiboles from this mafic sheet lack Eu anomalies implying that amphibole crystallization occurred prior to major plagioclase fractionation.
Chemical evidence reveals that magma mixing played an important role in controlling the chemical composition of individual sheets and field observations suggesting that there was a range of mixing styles. Throughout the sheeted complex, there are localized sites of mechanical mixing where plagioclase phenocrysts from adjacent felsic sheets are mechanically mixed into mafic sheets. Evidence for mechanical mixing is present across both sharp and gradational contacts. This implies varying rheological and viscosity contrasts between different sheets, though in both cases crystallinity and viscosity appears sufficiently low to allow crystals to migrate across sheet contacts.
Variability in sheet thickness and contact type suggests that the physical parameters (i.e. temperature, viscosity, rheology, and magma flux) of the system continue to evolve throughout the formation of the sheeted complex. Near the White River, sheets are thin and more heterogeneous but become progressively thicker (>302 m) and more felsic in composition up-section. The composition of plagioclase and amphibole is remarkably uniform in all of the felsic sheets suggesting that each sheet formed from an array of felsic parental magmas. Thicker, felsic sheets most likely reflect hotter conditions where larger magma fluxes could be accommodated or viscosity-temperature contrasts that were low enough to allow for efficient mixing between two adjacent sheets and therefore erase sheet contacts.Graduation Date: 2013