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Showing 1 to 20 of 25 for “"Titanite"”.
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The crystal chemistry of titanite
… substitutions of primary importance in natural titanites are (Al,Fe)<sup>3+</sup> + (F,OH)<sup>-</sup> ⇆ T<sub>1</sub><sup>4+</sup> + O<sup>2-</sup> , where total Al + Fe is not greater than 30 mol % and Al is usually predominant. Electron microprobe analyses and bond strength considerations …
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Titanite zoning and magma mixing
Titanite is a calcium titanium silicate accessory mineral that serves as a sink for trace elements, especially the rare-earth elements and the high-field strength elements (Cerny and Rivadisa.L 1972; Groat, Carter et al. 1985; Enami, Suzuki et al. 1993; Perseil and Smith 1995; Della Ventura, …
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Structural phase transitions in synthetic analogues of the titanite structure type
… this aim, synthetic derivatives of the mineral titanite, CaTiOSiO4, are used as model compounds. The study is focusing on the occurrence of displacive phase transitions in compounds with the 2:4:4 cation charge combination: SrTiOGeO4, CaTiOGeO4, CaZrOGeO4 and the binary solid solutions …
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Structural study of the auriferous Santoy shear zone, northeastern Glennie domain, Saskatchewan
… with the main stage mineralization event. Titanite and zircon within this assemblage was dated to 1755.5 ± 8.4 Ma (titanite) and 1754.0 ± 1.8 Ma (zircon) indicating syn-D3 deposit formation. A beryliferous pegmatite dyke that displays an F3 axial planar cleavage and crosscuts the auriferous …
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Exhumation, rift-flank uplift, and the thermal evolution of the Rwenzori Mountains determined by combined (U-Th)/He and U-Pb thermochronometry
… (U-Th)/He and U-Pb analysis of apatite, titanite, and zircon separated from crystalline basement rocks was conducted across the Rwenzori block to characterize the timing and rate of rift-flank exhumation related to continental extension in east-central Africa. The thermochronologic data …
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Multi-stage orogenic gold mineralization of the Pine Lake greenstone belt: evidence from the Seabee Gold Operation, Trans-Hudson orogen, northern Saskatchewan
… sericite-biotite-chlorite-clinozoisite ± albite, titanite to vein-adjacent to coarse-grained diopside-K-feldspar-albite-actinolite ± apatite, titanite calc-silicate alteration, associated with main-stage Py3a, 3b-Cpy2-Po1-Au (syn-late D3) mineralization; ii) remobilized, fracture-filling …
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A thermotectonic framework for the growth and stabilization of the eastern Kaapvaal craton, southern Africa
… lithosphere. Detailed U-Pb apatite and titanite thermochronological datasets are used in combination with finite difference numerical modeling to determine non-linear temperature-time paths for rocks between -650-300 °C from 3.45-3.08 Ga - providing a sensitive indicator of tectonic and …
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Tectonic Transport Directions and Timing of Metamorphism in the southern part of the Northern Highlands Terrane, Scotland
… deformation (< c.675 °C) are indicated by Zr-in-titanite thermometry and microstructural evidence for both quartz and feldspar grains dynamically recrystallizing by grain boundary migration processes. These early high temperature microstructures are partially-completely overprinted by lower …
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Petrogenesis of Mesoarchean high-K rocks in the Kaapvaal Craton: Investigating the Boesmanskop Alkaline Complex and Salisbury Kop batholith
… cores of ca. 3220 Ma. Zircon, apatite, and titanite compositions reflect high-temperature crystallization from REE-rich felsic magmas, with Ti-in-zircon thermometry recording temperatures up to 915 °C. Additionally, the high K2O+Na2O, low MgO and CaO contents of all the rocks, the presence …
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Geological and thermochronological evolution of the lower crust of southern Africa
… and magmatism. Utilizing the U-Pb systematics of titanite, apatite and rutile- minerals with closure temperatures for Pb diffusion of 650 to 400ʻC- the thermal evolution of the lower crust and underlying lithosphere has been constrained. Thermal relaxation times for the lithosphere following …
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Petrogenesis of a migmatite, Penobscot County, Maine: ultrametamorphism or intrusion?
… hornblendebearing inclusions, primary titanite, allanite, hornblende, and apatite included in biotite or hornblende), or S-type (tourmaline and red-brown biotite). They are conformable with melanosome (Bucksport) layering, and vary in outcrop from 7-88% areally, and in composition from …
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Geochemistry of igneous rocks from the southern coast belt plutonic complex, southwestern British Columbia
… sorting of plagioclase + hornblende + biotite ± titanite ± apatite for the mafic suite and sorting of plagioclase + biotite + K-feldspar titanite ± apatite for the felsic suite. Pearce element-ratios were employed to discriminate the mineral assemblages and to test these two hypotheses on samples …
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Reassessing the Holleford impact structure: Applying modern techniques to a classic Canadian crater
… microstructures identified as {-111} twins in titanite, a feature which previous studies have hypothesized to be diagnostic of shock deformation at pressures between 12-17 GPa, were observed in one Holleford sample. Shock pressures for drill hole 2 were constrained to below 20 GPa, due to the …
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The Structure and Behavior of Plate Boundary Regions Through the Wilson Cycle
… and U-Pb isotopic compositions for monazite and titanite. These datasets provide quantitative constraints on the style and conditions of deformation in the weak middle crust beneath an orogenic strike-slip conjugate shear system (in the upper crust). Furthermore, this data constrains the late …
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Petrology and Geochemical Evolution of the East Hill Suite of the Mont Saint-Hilaire Alkaline Plutonic Complex
… oxygen fugacity with cooling, and phases such as titanite (present) and aenigmatite (absent) defined boundaries in fO2 – T space. Oxygen fugacity data combined with petrography and geothermometry defined an 2 fO – T curve for the East Hill suite magma, revealing that the oxygen fugacity ranged …
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Investigations of Trace Element Titanium in Silica Minerals
… that synthesized quartz in the presence of titanite at sub-unity titania activity (????2) conditions. Ti-in-quartz concentrations and known experiment P–T conditions were entered into the TitaniQ solubility models to estimate ????2 values for the experimental system. The estimated …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 2)
… oxide, lesser olivine and accessory apatite and titanite (sphene). With the exception of a few hypersthene- and even quartz-normative samples, all of the rocks analysed are moderately to strongly silica-undersaturated, nepheline-normative lavas. On Grande Comore, the youngest island in the …
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The geochemistry and petrogenesis of lavas from the Comores Archipelago, Western Indian Ocean (Volume 1)
… oxide, lesser olivine and accessory apatite and titanite (sphene). With the exception of a few hypersthene- and even quartz-normative samples, all of the rocks analysed are moderately to strongly silica-undersaturated, nepheline-normative lavas. On Grande Comore, the youngest island in the …
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The kimeerlite occurrences from the vicinity of Rayton, South of premier mine, and from East Lynne, East of Pretoria
… results in the alteration of perovskite to titanite during this stage. Stage V represents mainly the metamorphism of serpentine to tremolite and actinolite owing to a rise in temperature in the kimberlite. Crystallization of zeolites and hydrogrossularite constitutes the hypergene alteration …
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Petrografia, litoquímica, química mineral e termobarometria de rochas cálcioalcalinas de alto K de textura porfirítica, ediacaranas, no extremo NE da Província Borborema (NE do Brasil)
… and amphibole are the main mafic minerals; and titanite, opaque minerals, allanite, epidote, apatite and zircon are the accessories minerals. The Monte das Gameleiras granite shows metaluminous aluminium saturation index, whereas the others plutons metaluminous to peraluminous. In geochemical …
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