A new occurrence of yimengite-hawthorneite and crichtonite-group minerals in an orthopyroxenite from kimberlite: Implications for mantle metasomatism

Rezvukhin, Dmitriy I.; Alifirova, Taisia A.; Korsakov, Andrey V.; Golovin, Alexander V.

doi:10.2138/am-2019-6741

Cited by 9 publications

(14 citation statements)

References 54 publications

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“…The orthopyroxenite exhibits a coarse-grained texture and consists essentially of large (1-10 mm) subhedral enstatite crystals (Figure 1, Figure 2, and Figure 3a) with subsidiary clinopyroxene (sodic Cr-diopside), vein-like ("necklace") garnet (Cr-rich pyrope), and Cr-spinel (magnesio-chromite) occurring interstitial to enstatite. The electron microprobe data on the compositions of the rock-forming minerals have been reported elsewhere [27]. Enstatite grains are densely populated by numerous preferentially oriented lamellae of diopside and fine platelets (0.1-5 µm in thickness) of magnesio-chromite ( Figure 1, Figure 2, and Figure 3a), with their compositions being identical to those of intergranular diopside and magnesio-chromite grains.…”

Section: Sample Petrographymentioning

confidence: 65%

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A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

et al. 2020

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More than forty mineral species of epigenetic origin have been identified in an orthopyroxenite from the Udachnaya-East kimberlite pipe, Daldyn kimberlite field, Siberian platform. Epigenetic phases occur as: (1) Mineral inclusions in the rock-forming enstatite, (2) daughter minerals within large (up to 2 mm) crystallized melt inclusions (CMI) in the rock-forming enstatite, and (3) individual grains and intergrowths in the intergranular space of the xenolith. The studied minerals include silicates (olivine, clinopyroxene, phlogopite, tetraferriphlogopite, amphibole-supergroup minerals, serpentine-group minerals, talc), oxides (several generations of ilmenite and spinel, rutile, perovskite, rare titanates of the crichtonite, magnetoplumbite and hollandite groups), carbonates (calcite, dolomite), sulfides (pentlandite, djerfisherite, pyrrhotite), sulfate (barite), phosphates (apatite and phosphate with a suggested crystal-chemical formula Na2BaMg[PO4]2), oxyhydroxide (goethite), and hydroxyhalides (kuliginite, iowaite). The examined epigenetic minerals are interpreted to have crystallized at different time spans after the formation of the host rock. The genesis of minerals is ascribed to a series of processes metasomatically superimposed onto the orthopyroxenite, i.e., deep-seated mantle metasomatism, infiltration of a kimberlite-related melt and late post-emplacement hydrothermal alterations. The reaction of orthopyroxene with the kimberlite-related melt has led to orthopyroxene dissolution and formation of the CMI, the latter being surrounded by complex reaction zones and containing zoned olivine grains with extremely high-Mg# (up to 99) cores. This report highlights the utility of minerals present in minor volume proportions in deciphering the evolution and modification of mantle fragments sampled by kimberlitic and other deep-sourced magmas. The obtained results further imply that the whole-rock geochemical analyses of mantle-derived samples should be treated with care due to possible drastic contaminations from “hiding” minor phases of epigenetic origin.

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Section: Sample Petrographymentioning

confidence: 65%

“…A considerable diversity of epigenetic minerals was established in the orthopyroxenitic part of the xenolith. Using a set of conventional geothermobarometers, the P-T equilibration parameters of the orthopyroxenite have been estimated to be as high as~800 • C and~35 kbar ( [27] and references therein).…”

Section: Sample Petrographymentioning

confidence: 99%

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

et al. 2020

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“…An examination of various inclusions in mantle minerals allows to access the mantle processes responsible for genesis and transformation of deep-seated rocks (e.g., other studies [24,41,42,45,61,64] ). Complex alkali-and large ion lithophile element-bearing titanates of the crichtonite group along with magnetoplumbite group minerals (e.g., other studies [41,62,65] ) are commonly reported as metasomatic oxides from the subcontinental mantle settings, both on-and off-cratonic. The members of both groups are present in xenoliths and/or as xenocrysts sampled by kimberlites, lamprophyres, and alkali basalts.…”

Section: Implications For Mantle Petrologymentioning

confidence: 99%

“…[40,45] Enstatite-hosted CGM inclusions have been recently recognized in an orthopyroxenite from Udachnaya. [41,75] The CGM-bearing samples from Siberia are known to have been equilibrated at pressures of 2.5-4.2 GPa and temperatures of 650 C-850 C. [22,24,[39][40][41]73] Mantle CGM are considered to be a valuable reservoir of a large number of high field strength, large ion lithophile, and REE with their abundance up to 100 chondritic units. [10,16,26,76] This fact together with CGM stability at high pressures and temperatures makes them potentially important repository for rock-forming mantle silicate-incompatible trace elements, together with well-known metasomatic minerals-phlogopite, amphibole, and carbonates-and, thus, provides clues to fluid and magma generation at upper-mantle conditions and metasomatism of the depleted lithospheric mantle.…”

Section: Implications For Mantle Petrologymentioning

confidence: 99%

“…However, the identification of CGM in a mantle material is mainly confined to the measurements of their composition by means of electron microprobe and scanning electron microscope (SEM), whereas the structural data are usually challenging to obtain, especially taking into account a common small size of the grains (e.g., other studies [37,[40][41][42] ). In light of the aforementioned, the micro-Raman spectroscopic technique serves as a helpful tool for the express and accurate diagnostics of CGM, which is highly applicable to a study of inclusions in mantle minerals.…”

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Micro‐Raman study of crichtonite group minerals enclosed into mantle garnet

Alifirova

Rezvukhin

Николенко

et al. 2020

J Raman Spectroscopy

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We report the first comprehensive micro‐Raman study of crichtonite group minerals (CGM) as inclusions in pyropic garnet grains from peridotite and pyroxenite mantle xenoliths of the Yakutian kimberlites as well as in garnet xenocrysts from the Aldan shield lamprophyres (Russia). The CGM form (i) morphologically oriented needles, lamellae, and short prisms and (ii) optically unoriented subhedral to euhedral grains, either single or intergrown with other minerals. We considered common mantle‐derived CGM species (like loveringite, lindsleyite, and their analogues), with Ca, Ba, or Sr dominating in the dodecahedral A site and Zr or Fe in the octahedral B site. The Raman bands at the region of 600–830 cm−1 are indicative of CGM and their crystal‐chemical distinction, although the intensity and shape of the bands appear to be dependent on laser beam power and wavelength. The factor‐group analysis based on the loveringite crystal structure showed the octahedral and tetrahedral cation groups with 18f and 6c Wyckoff positions, namely, dominantly TiO6 and to a lower extent CrO6, MgO4, and FeO4 groups, to be the major contributors to the Raman spectral features. The ionic groups with dodecahedral (M0) and octahedral (M1) coordination are inactive for Raman scattering while active in infrared absorption. A number of observed Raman modes in the CGM spectra are several times lower than that predicted by the factor group analysis. The noticed broadening of modes in the CGM Raman spectra may result from a combining of bands at the narrow frequency shift regions. Solid solution behavior, luminescence, and partial metamictization of the CGM may exert additional influence on the Raman band shape. The Raman spectral features showed CGM to be accurately identified and distinguished from other Ti‐, Fe‐, Cr‐, and Zr‐containing oxides (e.g., ilmenite or those of spinel and magnetoplumbite groups) occurring as accessory mantle minerals.

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Perovskite geochronology and petrogenesis of the Neoproterozoic Mad Gap Yards ultramafic lamprophyre dykes, East Kimberley region, Western Australia

Downes

Jaques

Talavera

et al. 2023

Contrib Mineral Petrol

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The Mad Gap Yards ultramafic lamprophyre (UML) dykes in the East Kimberley region of northern Western Australia form part of a widespread Neoproterozoic (~842-800 Ma) alkaline mafic-ultramafic magmatic province in the north, east and central regions of the Kimberley Craton of Western Australia. The NE-trending Mad Gap Yards dykes lie at the southeastern margin of the Kimberley Basin adjacent to the Greenvale Fault and intrude the Paleoproterozoic Elgee Siltstone. The dykes are classified as alnöite, and contain abundant macrocrystic olivine in a groundmass of phlogopite, perovskite, spinels, diopside, apatite, andradite-hydroandradite, serpentine, calcite, pseudomorphs after melilite and rare gittinsite. Mantle-derived olivine macrocrysts have compositions in the range Mg#91-92, similar to moderately refractory peridotite from other parts of the Kimberley Craton, whereas magmatic olivine phenocrysts have Mg#88-90. Olivine and chromian spinel were the earliest phenocrysts; they record equilibration temperatures of ~1030-920˚C under moderately reducing conditions with fO2 values below the fayalite-magnetite-quartz (FMQ) oxygen buffer (Δ FMQ = mostly -0.8 to -1.7 log units). Magnetite rims and groundmass grains crystallised at ~850-740˚C under more oxidising conditions with Δ FMQ ~+0.6 to -0.75 log units. Perovskite is well preserved in parts of the dykes and indicates crystallisation inside this fO2 range. The perovskite yielded a SHRIMP 206Pb/238U age of 842±8 Ma. The Mad Gap Yards dykes carry rare partially-altered spinel peridotite xenoliths containing olivine (Mg#86.3-90), Cr-diopside, enstatite and Al-Cr spinel, and well as

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A new occurrence of yimengite-hawthorneite and crichtonite-group minerals in an orthopyroxenite from kimberlite: Implications for mantle metasomatism

Cited by 9 publications

References 54 publications

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

A Plethora of Epigenetic Minerals Reveals a Multistage Metasomatic Overprint of a Mantle Orthopyroxenite from the Udachnaya Kimberlite

Micro‐Raman study of crichtonite group minerals enclosed into mantle garnet

Perovskite geochronology and petrogenesis of the Neoproterozoic Mad Gap Yards ultramafic lamprophyre dykes, East Kimberley region, Western Australia

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