With it, we assess the role of fractional crystallization in controlling the Fe isotopic evolution of a mafic magma. The UUMZ evolved by fractional …
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Differentiation of mantle-derived, hydrous, basaltic magmas is a fundamental process to produce evolved intermediate to SiO2-rich magmas that form the bulk of the middle to shallow continental and island arc crust. This study reports the results of fractional crystallization experiments conducted in a piston cylinder apparatus at 0.7 GPa for hydrous, calc-alkaline to …
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However, fractional crystallization of magnetite (ρ = 5.1 ∼ 5.2 g/cm3) will locally significantly decrease the density of basaltic melt to induce simultaneous sinking of plagioclase to form ...
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Such a depletion is thought to originate primarily due to the fractional crystallization of magnetite from a limited volume of liquid 7,13,34 and the extremely high crystal–liquid partition ...
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Previous studies have shown a rapid cooling and a high H2O content of the Jiaodong mafic magma. Combine with the garnet-spinel transition zone of mantle lithosphere and magnetite observed in petrography, we tend to propose that the variation in oxygen fugacity of mafic magma were caused by magnetite-spinel fractional crystallization at depth.
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fractional crystallization of magnetite from a homogeneous body. of melt containing 57 ppm Cr 3, 27, with f. O2. between zero and one. log unit below the quartz-fayalite-magnetite oxygen buffer (i.e.,
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Fractional crystallization is understood to be an important process for Earth's magmatic systems and appears to be important wherever molten magma cools slowly enough to allow minerals to nucleate, grow, and separate from a residual liquid. The removal of silica-poor minerals like olivine (~ 40% SiO 2) or Fe–Ti oxides (0% SiO 2) typically drives the silica content of the residual …
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The mass–temperature plots indicate that fractional crystallization was significantly affected by the recharge and assimilation processes, whereas the contaminated magma recharge favored the early crystallization of Fe–Ti oxides as well as the formation of the PGE-bearing immiscible melt in the lower part of the intrusion.
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Injections of this melt form magnetite orebodies by crystallization of magnetite (mt; gray) and diopside (di; green). Fractional crystallization drives the melt toward sulfate (anhydrite [anhy]; pink)–dominated composition, leading to formation of sulfate-rich veins and alteration. asl—above sea level; Fm—Formation.
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Igneous rocks. Fractional crystallization is the removal and segregation from a melt of mineral precipitates; except in special cases, removal of the crystals changes the composition of the magma. In essence, fractional crystallization is the removal of early formed crystals from an originally homogeneous magma (for example, by gravity settling) so that these crystals are …
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Ilmenite and magnetite's association with primitive rocks, such as trocholite and pyroxene gabbro, indicate that fractional crystallization from Fe–Tirich parental magma had occurred 41,42.
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Iron (Fe) isotopes have been used to trace magmatic evolution (e.g., mineral fractional crystallization, partial melting degree, and fluid exsolution), but the behavior of Fe …
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Given that the depletion of Fe in magmas is not only controlled by the fractional crystallization of Fe-rich minerals but may also be influenced by fluid exsolution in the later stages of magmatism (Poitrasson and Freydier, 2005; Heimann et al., 2008), we have assessed the potential impacts of fluid activity and fractional crystallization on Fe ...
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P-T-H 2 O conditions during multistage fractional crystallization, ... The stoichiometric calculations revealed that these crystals have different proportions of magnetite (0–97%), ulvöspinel (0–97%), spinel (1–66%) and chromite (0–33%) molecules through a solid-solution (Fig. 6). Chromite molecule is present only in opaque minerals ...
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The crystallization of small amounts of magnetite and its influence on ilmenite composition is also examined. ... SW Norway, constrains a two stage fractional crystallization model of a ferrodioritic Fe-Ti-P rich melt. Stage 1 is characterized by ilmenite-plagioclase cumulates, partly stored in the lower part of the ore body (Lower Central Zone ...
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fractional crystallization of magnetite from a homogeneous body of melt containing 57 ppm 118. Cr 3,25, with f O 2 between zero and one log unit below the quartz-fayalite-magnetite oxygen 119.
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While magnetitites contain foliated plagioclase grains in non-cotectic proportions, the magnetite is characterized by a regular upwards-depletion of Cr which is best explained by …
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Magnetite chemistry by laser ablation-inductively coupled plasma-mass spectrometry records sulfide fractional crystallization in massive nickel-copper-platinum group element ores from the …
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However, the fractional crystallization of K-feldspar can lead to reduced Sr and K 2 O contents and K 2 O/Na 2 O ratios. ... Amphibole, biotite, garnet, and magnetite are the primary Fe-bearing minerals in the Kampa leucogranite, and their fractional crystallization plays a crucial role in the variation of Fe isotope compositions ...
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Equilibrium fractional crystallization calculations were performed isobarically at 200 MPa along the quartz–fayalite–magnetite (QFM) buffer, using the bulk chemical analyses of our FC-1 sample as the starting composition.
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The origin of the carbonatites that appear on Earth is one of the most controversial current topics in the petrogenesis of igneous rocks. Situated in the northern sector of the Basal Complex of Fuerteventura (Canary Islands), the Miocene Esquinzo ultra-alkaline plutonic rock complex is composed of pyroxenites, melteigites-ijolites-urtites, malignites-nepheline syenites, …
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fractional crystallization of magnetite from a homogeneous body of melt containing 57 ppm Cr 3,27, with f O2 between zero and one log unit below the quartz-fayalite-magnetite oxygen buffer (i.e.,
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The mineral phases that formed during the fractional crystallization process of the Jeju low-alumina alkaline magma include olivine, clinopyroxene, plagioclase and magnetite (Tatsumi et al., 2005). Hence, the absence of olivine from 2.0 GPa to 1.4 GPa is incompatible with the mineral assemblage of the Jeju alkaline rocks.
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However, the conventional fractional crystallization model suggests that magnetite starts to crystallize at 1151 °C at around 10% fractional crystallization and continues to crystallize until the appearance of apatite (Song et al., 2013). Therefore, the duration of magnetite fractionation constrained by V isotopic compositions in the lower ...
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Here we address the origins of the Main Magnetite Layer, a globally important resource of Fe-Ti-V-rich magnetite. Previous models of in situ fractional magnetite …
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fractional crystallization, postcumulus evolution ... magnetite with stratigraphic height, from 0 to ca. 3 wt%, results from differentiation of the trapped li-quid towards magnetite saturation. The MgO content of ilmenite (1.4–4.4 wt%) is much lower than the ex-
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While fractional crystallization has been shown to influence the chemistry of igneous magnetite, the extent to which this process regulates the trace element composition of hydrothermal...
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The Baima layered intrusion is located in the central part of the Emeishan Large Igneous Province (ELIP). The N–S striking intrusion is ~ 24 km long and ~ 2 km thick and dips to the west. Based on variations in modal proportions and cumulus mineral assemblages, the intrusion from the base to the top is simply subdivided into a lower zone (LZ) with most of the …
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