However the intraplate garnet pyroxenite from Kakanui has lower Al than the bulk of continental eclogites and the Malaita garnet pyroxenite has a higher Mg content. Eclogites do not have the low Al and high Mg characteristics of some garnet pyroxenites, exemplified by the garnet pyroxenite from Bultfontein which has much lower Al than published ...
Pyroxenite is denser than eclogite but also has higher bulk and shear moduli, which make it seismically faster. The impedance contrast across a possible pyroxenite-eclogite …
Examination of 344 clinopyroxene analyses with Fe 2 O 3 content quoted suggests that for certain parageneses the sum of cations based on 6 oxygens approaches the ideal value of 4.00.However, for sub-calcic and jadeitic pyroxenes, deviations from ideality become significant.Hence, calculation of ferric and ferrous iron proportions, on the ...
pyroxenite, dark-coloured, intrusive igneous rock that consists chiefly of pyroxene.Pyroxenites are not abundant; they occur in discrete inclusions, in layered sills (tabular bodies inserted between other rocks) and lopoliths (laccoliths with basin-shaped bases), in branching veins, in narrow dikes (tabular bodies injected in fissures), and at the edges of silica-poor plutons …
Pyroxenites are ultramafic intrusive igneous rocks composed almost entirely of dark Pyroxene group minerals rich in iron and magnesium, e.g., Augite, Diopside, Hypersthene, Diallage, …
Pyroxenite—recycled, subducted material—beneath mid-ocean ridges cools the mantle, suppressing melt extraction and crust formation, according to geochemical analyses of samples taken from the ...
Pyroxenite is an ultramafic igneous rock consisting essentially of minerals of the pyroxene group, such as augite, diopside, hypersthene, bronzite or enstatite. Pyroxenites are classified into clinopyroxenites, orthopyroxenites, and the websterites which contain both types of pyroxenes (see diagram below). Closely allied to this group are the ...
The mineralogy of pyroxenite rock revealed lizardite, olivine, enstatite, grunerite, clinoferrosilite, and chromite. The study of melting behavior showed that the melting of pyroxenite samples starts at 1491.5 °C, and complete melting occurs at 1514.7 °C. The plant performance during the pyroxenite trial period was improved compared to the ...
Olivine-hosted melt inclusions within the Xinkailing HMAs are alkaline and record a much lower SiO 2 content and higher Al 2 O 3 and CaO contents than the sub-alkaline bulk rock ... Pyroxenite and peridotite are the two main source lithologies of mantle-derived melts, which differ in their olivine chemistry and major element compositions ...
The Na 2 O content of liquid increases until the disappearance of feldspar, then Na 2 O behaves as an incompatible element. Moreover, at P > 3 GPa, the Na 2 O content in melts does not change significantly due to the increase of the relative compatibility of Na 2 O in residual Cpx (e.g., Pertermann and Hirschmann, 2003, Spandler et al., 2008).
The mineralogy of pyroxenite rock revealed lizardite, olivine, enstatite, grunerite, clinoferrosilite, and chromite. The study of melting behavior showed that the melting of pyroxenite samples starts at 1491.5 °C, and complete melting occurs at 1514.7 °C.
Previous work suggested that the fractionation of a pyroxenite assemblage with 30 modal % garnet from a hydrous primitive magma can remove up to 60% of the Fe from the melt while increasing its fO 2 by as much as six …
Pyroxenite, dark-coloured, intrusive igneous rock that consists chiefly of pyroxene. Pyroxenites are not abundant; they occur in discrete inclusions, in layered sills (tabular bodies inserted …
Carbon mineralization in mafic-ultramafic rocks is not only a natural process that can form significant carbon sinks in the lithosphere, but also a promising procedure for artificial CO 2 storage. In this study, we report unique records of in situ carbon mineralization within fluid inclusions in postcollisional pyroxenite from the Dabie orogen, central China.
A classification diagram of ultramafic rocks. Pyroxenite is yellow, peridotite white.
The determination of ferrous-ferric ratios was achieved by a wet chemical microcolorimetric method as proposed in Schuessler et al. and Vetere et al. . A rotational Anton Paar RheolabQC viscometer head, equipped with a …
Partial melts of hybrid peridotite-pyroxenite sources have higher NiO and SiO 2 and lower CaO and MgO than melts of pure peridotite, on this basis it was suggested that pyroxenite contributes ~30% ...
The pyroxenite spectra have strong narrow absorption at 700 nm due to the presence of ferrous iron (Fe 2+), and ferric iron (Fe 3+) intervalence charge transfer, moderate symmetrical absorption observed at 1010 nm due to clinopyroxene (Cpx), a moderate narrow symmetrical absorption observed at 1400 nm due to the OH/Mn 3+ crystal transition, a ...
Perlite is an extrusive rock that forms when a high-silica lava has a high water content. It is an important industrial material. This type of igneous rock forms when a body of rhyolite or obsidian, for one reason or another, has a …
In fact, the low silica content of OIB from recycled sources could be explained by partial melting of a range of peridotite compositions. However, experimentally ... Thus, a pyroxenite with less SiO 2 than MIX1G can produce partial melts with less SiO 2 and less Al 2 O 3 contents, that is, liquids more similar to OIB parental liquids at similar ...
Pyroxenites are diffuse in fertile mantle peridotites and considered an important component in the mantle source of oceanic basalts. They are rarely documented in abyssal and ophiolitic peridotites representing residual mantle after melt generation, and few studies defining their origin are to date available. We present a field-based microstructural and geochemical …
Field and petrographic evidence indicate that pyroxenite formation preceded the melt–rock interaction history that affected this mantle sector during Jurassic exhumation, …
A pyroxenite is an ultramafic plutonic rock consisting of ≫60% pyroxene (either clino- or orthopyroxene, or both). Other phases include olivine, hornblende, micas, garnet, feldspar, spinel, ilmenite, and sulfides. They have a gradational relationship with peridotites.
Analyses of these minerals from peridotite xenoliths and less abundant mantle pyroxenites using Möss spectroscopy indicate that the Fe 3+ content of fertile upper …
Rudolph et al. [] analyzed the long-wavelength nonhydrostatic geoid, allowing the depths of possible viscosity jumps to vary, and found that the best fitting models require significant viscosity increase in the 800–1200 km …
Garnet pyroxenite xenoliths from Hawaii have 256–467 ppm bulk H 2 O.. These H 2 O concentrations are 2 to 4 times higher than the MORB source.. The pyroxenite H 2 O/Ce ratios (35–115) are lower than the MORB source.. The high H 2 O, low H 2 O/Ce suggests a link between pyroxenites and EM-type OIB.. We suggest a link between mineralogy and water …
The chemical composition of pyroxenite (sample 308-g) corresponds to the rock-forming mineral of the Ca(Mg, Fe, Al) pyroxene group [(Si, Al) 2 O 6] with heightened weight content of Cr 2 O 3 (up to 2.8%). The presented sample is characterized by a high content of magnesium and calcium oxides.
We present high-precision iron and magnesium isotopic data for diverse mantle pyroxenite xenoliths collected from Hannuoba, North China Craton and provide the first combined iron and magnesium isotopic study of such rocks. Compositionally, these xenoliths range from Cr-diopside pyroxenites and Al-augite pyroxenites to garnet-bearing pyroxenites …
In this paper, we evaluate the contribution of peridotiteversus pyroxenite-derived melts to arc magmatism as a function of the crustal thickness of the overriding plate.
Majoritic garnet is one of the main constituents of the lowermost upper mantle and the mantle transition zone, comprising up to 35 vol% in peridotitic and up to 95 vol% in eclogitic lithologies (Wood et al. 2013).Despite having a wide stability field (~7–26 GPa) and being one of the most common minerals in Earth's mantle, the compositions of natural majoritic garnets are …
Pyroxenite samples are comprised primarily of pyroxene, olivine, magnesium-rich amphibole (anthophyllite) and chromite. Peridotite samples observed to have olivine, pyroxene, ... The ferrous iron content in the ultramafic rocks is dominant and complies with the deeper absorption band around 1.03 µm. For dunite, ...
Pyroxenite composition is contain at least 90 percentpyroxene group minerals, such as as augite, diopside, hypersthene, bronzite orenstatite.Pyroxenite also contain olivine and oxide minerals. Pyroxenite hasless olivine than peridotites. The principal minerals usually foundaccompanying …
Pyroxene, any of a group of important rock-forming silicate minerals of variable composition, among which calcium-, magnesium-, and iron-rich varieties predominate. Pyroxenes are the most significant and abundant group of rock …
