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Showing 1 to 20 of 39 for “"granitoid"”.
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A geophysical investigation of a concealed granitoid beneath Lumberton, North Carolina
… range are interpreted to be from the base of the granitoid at a depth of about 17 km. One possible explanation for these reflections is that the granitoid is allochthonous; emplaced elsewhere and then transported to its present position along a sole thrust. The high heat flow suggests that the …
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Seismic Imaging of a Granitoid-Greenstone Boundary in the Paleoarchean Pilbara Craton
… acquired deep seismic reflection data crossing a granitoid-greenstone boundary. Their processing did not image the geologically mapped steep dip of the boundary because standard methods limit the maximum dip. A 37-km section of these data were reprocessed using 2D Kirchhoff prestack depth …
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Association of S-type and I-type granitoids in the Neoproterozoic Cameroon orogenic belt, Bafoussam area, West Cameroon : geology, geochemistry and petrogenesis
… surface of ~1000 km2 and dominantly consists of granitoids which intruded wall-rocks of gneiss and migmatite during the Pan-African orogeny. The Bafoussam granitoid emplacement was influenced by the N 30 °E strike-slip shear zone in the prolongation of the Cameroon Volcanic Line, but also by the …
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Sodium metasomatism and magnesio-riebeckite mineralization in the Wilson Ridge pluton
… crystals. Oxygen isotope studies suggest that granitoid rocks containing hydrothermal amphiboles have lower delta18O values (+3.68‰ to +6.97‰) than unaltered granitoid rocks (delta 18O values +6.04‰ to +9.23‰).
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The Foyers Granitic Complex and its aureole
… minor anatexis occuring in the inner aureole. Granitoid fabrics, enclaves, xenoliths and internal contacts imply emplacement whilst in a magmatic state. The adamellite was emplaced into a solid pluton. Boudinage and shearing in envelope psammites, and intense solid state fabrics in pre-Foyers …
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Investigation of aggregate properties influencing railroad ballast performance
… materials featured eight trap rocks, four granitoid rocks, one aggregate composed of approximately half trap and half granitoid rock, and one quartzite rock. First, the physical properties of all ballast aggregate materials were determined. First, gradation, specific gravity, absorption, …
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Structural and petrologic aspects of the emplacement of granitoid plutons : case studies from the western margin of the Joshua Flat-Beer Creek-Pluton (White-Inyo Mountains, California) and the Flasergranitoid zone (Odenwald, Germany)
… the field observations. The plutons of the Flasergranitoid Zone in the Crystalline Odenwald Zone intruded around 325 Ma ago. Intrusion conditions of five dioritic to granitic plutons were determined with hornblende geothermobarometry. The plutons intruded into a depth of 13 to 20 km at …
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Granulite-facies metamorphism, fluid buffering and partial melting in the Buffels River area of the Namaqualand metamorphic complex, South Africa
… volcano-sedimentary gneisses intruded by granitoid orthogneisses. This study concentrates on the mechanisms of granrilite-facies metamorphism in a small area of isofacial rocks. Particular emphasis is placed on the role of partial melting and the infiltration and buffering of metamorphic …
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High-resolution temporal records of magmatism, sedimentation, and faulting at evolving plate boundaries
… 3 quantifies magma emplacement rates in a large, granitoid intrusive complex (Golden Horn batholith) that was emplaced during Paleogene ridge-trench interaction. Parts of this batholith were constructed at the highest rate ever documented in a large granitoid intrusive complex (~0.0125 km³/a). …
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Geologic framework of gravity anomaly sources in the central Piedmont of Virginia
… Arvonia Formation-2.77 gm/cc, Columbia Granitoid-2.75 gm/cc (tonalite) and 2.73 gm/cc (pegmatite), Chopawamsic Volcanics- 2.77 gm/cc (felsic units), and 2.79 gm/cc (mafic units}, Catoctin/ Lynchburg-2.815 gm/cc, Maidens Gneiss-2.775 gm/cc, Grenville Basement- 2.71 gm/cc. Gravity and …
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Mineralogy and provenance of the TiO₂ - ilmenite heavy mineral sand deposit of Nataka
… and rutile indicate major contribution from granitoid terranes, subjected to granulite metamorphic facies (750 to 1000 :C), and minor contribution from mafic plutonic intrusions. The granitoid field as a sediment source area if analysed in conjunction with zircon ages (1100 – 900 Ma, 900 – …
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MULTISCALE GEOCHEMICAL STUDY OF THE CORNO ALTO COMPLEX (ADAMELLO BATHOLITH)
Granitoid batholiths are important end products of the Earth’s long-term compositional differentiation, representing either the addition of juvenile material to the crust or the reworking of older crustal components. The nature and composition of crustal granitoids significantly changed at the …
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Granite petrogenesis and crustal evolution studies in the Damara Pan-African orogenic belt, Namibia
Major and trace element data for Damara granitoids distinguish three geochemically distinct granitoid groups, - crustal-melt granitoids, calc-alkaline granitoids and within-plate granitoids. The overwhelming majority of the Oamara granitoids are peraluminous crustal-melt leucogranites which have …
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Geochemical characterisation of Archaean granitoids in eastern Finland
… plates. Overall, the Karelian craton is a granitoid-greenstone terrain with prevailing TTGs and younger granites, which show increasing level of potassium. The craton also includes a distinct sodic variety of granites that combines features of classical Archaean TTGs and late Archaean …
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Geology of an Archean Greenstone Belt at Point Lake, Northwest Territories, Canada
… metasedimentary rocks lies over and east of a granitoid gneissic terrane. Field and laboratory studies have helped to clarify the petrography and structural relationships of this fold-and-thrust belt. Traditional models have suggested that granite-greenstone belts in the Slave Province are …
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Petrogenetic Relationship of the Postcaldera Eruptions of Mount Mazama, Crater Lake, Oregon; Evolution of a Sub-volcanic Magma Chamber Following a Large Silicic Eruption
… originated in the climactic magma chamber; granitoid antecrysts were part of the magma chamber wall rock; and andesite phenocrysts and basalt phenocrysts represent new magma or melt ± crystals in the postcaldera magma system.</p> <p>The postcaldera magma system of Mount Mazama’s climactic …
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Intensive parameters of a sulfide and aluminosilicate-bearing granite, Hancock County, Maine
… quartz-rich, leucocratic, two-mica, two-feldspar granitoid. It is marked by the presence of 1) sulfides (pyrrhotite, pyrite, loellingite, arsenopyrite, chalcopyrite, and sphalerite) 2) volatile-rich phases such as muscovite, tourmaline, apatite, and chlorite, and 3) high-temperature anhydrous …
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Bedrock and surficial geology of the southern half of the Montezuma 7.5' quadrangle, central Colorado Front Range, Colorado, USA
… gneiss. These are intruded by Mesoproterozoic granitoid plutonic rocks and local satellite intrusions related to the ~39.7 Ga Montezuma stock. The Paleoproterozoic rocks are deformed by isoclinal F1 folds in various orientations. These are overprinted by D2 structures, which include tight to …
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The evolution of the Archaean continental crust of Northern Zimbabwe
Granitoid clasts preserved in Late Archaean conglomerates indicate the presence of continental crust in Northern Zimbabwe prior to the"" 2.7 to "" 2.6Ga "event" which terminated with the stabilisation of the Zimbabwe Craton. The "Kober Technique" (Kober, 1986, 1987) of direct thermal ionisation of …
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