Sulfide-melt inclusions in mantle xenoliths of Hannuoba, China

1999 ◽  
Vol 44 (2) ◽  
pp. 166-170 ◽  
Author(s):  
Jiuhua Xu ◽  
Xuelei Chu ◽  
Yiming Zhou ◽  
Yuanfu Du
Keyword(s):  
Melt Inclusions ◽  
Mantle Xenoliths ◽  
Sulfide Melt

NI-RICH SULFIDE MELT INCLUSIONS IN YAKUTIAN DIAMONDS

2019 ◽  
Author(s):  
Alla M. Logvinova ◽  
◽  
Richard Wirth ◽  
Alexey O. Serebriannikov ◽  
Nikolay V. Sobolev
Keyword(s):  
Melt Inclusions ◽  
Sulfide Melt

Mineral assemblage within secondary crystallized melt inclusions in olivine of mantle xenoliths from the Bultfontein kimberlite pipe (Kaapvaal craton, South Africa)

2021 ◽  
Author(s):  
Alexey Tarasov ◽  
Igor Sharygin ◽  
Alexander Golovin ◽  
Anna Dymshits ◽  
Dmitriy Rezvukhin
Keyword(s):  
Melt Inclusions ◽  
Basic Research ◽  
Kimberlite Pipe ◽  
Mantle Xenoliths ◽  
Mantle Minerals ◽  
Source Regions ◽  
Basic Research Grant ◽  
Carbonate Composition ◽  
First Time ◽  
Ca Carbonate

<p>For the first time, snapshots of crystallized melts in olivine of sheared garnet peridotite xenoliths from the Bultfontein kimberlite pipe have been studied. This type of xenoliths represents the deepest mantle rocks derived from the base of lithosphere (at depths from 110 to 230 km for various ancient cratons). According to different models, such type of inclusions (secondary) in mantle minerals can be interpreted as relics of the most primitive (i.e., close-to-primary) kimberlite melt that infiltrated into sheared garnet peridotites. In general, these secondary inclusions are directly related to kimberlite magmatism that finally formed the Bultfontein diamond deposits. The primary/primitive composition of kimberlite melt is poorly constrained because kimberlites are ubiquitously contaminated by xenogenic material and altered by syn/post-emplacement hydrothermal processes. Thus, the study of these inclusions helps to significantly advance in solving numerous problems related to the kimberlite petrogenesis.</p><p>The unexposed melt inclusions were studied by using a confocal Raman spectroscopy. In total, fifteen daughter minerals within the inclusions were identified by this method. Several more phases give distinct Raman spectra, but their determination is difficult due to the lack of similar spectra in the databases. Various carbonates and carbonates with additional anions, alkali sulphates, phosphates and silicates were determined among daughter minerals in the melt inclusions: calcite CaCO<sub>3</sub>, magnesite MgCO<sub>3</sub>, dolomite CaMg(CO<sub>3</sub>)<sub>2</sub>, eitelite Na<sub>2</sub>Mg(CO<sub>3</sub>)<sub>2</sub>, nyerereite (Na,K)<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub>, gregoryite (Na,K,Ca)<sub>2</sub>CO<sub>3</sub>, K-Na-Ca-carbonate (K,Na)<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub>, northupite Na<sub>3</sub>Mg(CO<sub>3</sub>)<sub>2</sub>Cl, bradleyite Na<sub>3</sub>Mg(PO<sub>4</sub>)(CO<sub>3</sub>), burkeite Na<sub>6</sub>(CO<sub>3</sub>)(SO<sub>4</sub>)<sub>2</sub>, glauberite Na<sub>2</sub>Ca(SO<sub>4</sub>)<sub>2</sub>, thenardite Na<sub>2</sub>SO<sub>4</sub>, aphthitalite K<sub>3</sub>Na(SO<sub>4</sub>)<sub>2</sub>, apatite Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>(OH,Cl,F) and tetraferriphlogopite KMg<sub>3</sub>FeSi<sub>3</sub>O<sub>10</sub>(F,Cl,OH). Note that carbonates are predominant among the daughter minerals in the melt inclusions. Moreover, there are quite a lot of alkali-rich daughter minerals within the inclusions as well. During the last decade, some research groups using different approaches proposed a model of carbonate/alkali‑carbonate composition of kimberlite melts in their source regions. This model contradicts to the generally accepted ultramafic silicate nature of parental kimberlite liquids. This study is a direct support of a new model of carbonatitic composition of kimberlite melts and also shows that alkali contents in kimberlite petrogenesis are usually underestimated.</p><p>This work was supported by the Russian Foundation for Basic Research (grant No. 20-35-70058).</p>

Primary carbonatite melt inclusions in apatite and in K-feldspar of clinopyroxene-rich mantle xenoliths hosted in lamprophyre dikes (Hungary)

2008 ◽  
Vol 94 (3-4) ◽  
pp. 225-242 ◽  
Author(s):  
Tibor Guzmics ◽  
János Kodolányi ◽  
István Kovács ◽  
Csaba Szabó ◽  
Enikő Bali ◽  
...  
Keyword(s):  
Melt Inclusions ◽  
Mantle Xenoliths

Origin of noble-metal nuggets in sulfide-saturated arc magmas: A case study of olivine-hosted sulfide melt inclusions from the Tolbachik volcano (Kamchatka, Russia)

Geology ◽  
2020 ◽  
Vol 48 (6) ◽  
pp. 620-624
Author(s):  
Vadim S. Kamenetsky ◽  
Michael Zelenski
Keyword(s):  
Noble Metals ◽  
Melt Inclusions ◽  
Basaltic Magma ◽  
Sulfide Liquid ◽  
Direct Crystallization ◽  
Arc Magmas ◽  
Tolbachik Volcano ◽  
Sulfide Melt ◽  
Significant Uptake

Abstract Minerals that contain platinum-group elements (PGEs) and occur in some magmatic Cu-Ni sulfide deposits have been ascribed to crystallization from an originally PGE-rich sulfide liquid. The occurrence of PGE-bearing minerals (PGMs) in some sulfide-undersaturated primitive melts has been envisaged and recently reported, whereas direct crystallization of PGMs in sulfide-saturated silicate magmas is seemingly hindered by strong partitioning of PGE into immiscible sulfide melts. In this study, we discovered abundant nanoparticles containing noble metals in association with sulfide melt inclusions entrapped inside primitive olivine phenocrysts (Fo85–92) from the recent basaltic magma of the Tolbachik volcano (Kamchatka arc, Russia). These nuggets occur in swarms on the surface of the sulfide globules and are represented by native metals, sulfides, and alloys of Pd, Pt, Au, Pb, and Bi. The nuggets on different globules can be either Pd- or Pt-rich nuggets, and the compositions are highly variable, even among adjacent nuggets. We argue that the diffusive supply of Pd from the external nuggets can be responsible for significant uptake of Pd (up to 2 wt%) in the sulfide melt. We consider direct crystallization of PGMs in a primitive basaltic melt undergoing sulfide unmixing, and possibly sulfide breakdown due to oxidation, as another mechanism additional to their “classic” origin from the PGE-rich sulfide melt in response to solidification.

Features of heat and mass transfer processes under the Avachinsky volcano (Kamchatka)

2020 ◽  
Author(s):  
Grigory Kuznetsov ◽  
Victor Sharapov
Keyword(s):  
Mass Transfer ◽  
Mantle Wedge ◽  
Melt Inclusions ◽  
Publishing House ◽  
Mantle Xenoliths ◽  
Convective Heating ◽  
Fluid Filtration ◽  
Crust And Upper Mantle ◽  
Peridotite Xenoliths ◽  
Melt And Fluid Inclusions

<p>We investigated the processes beneath the Avacha volcano using mantle peridotite xenoliths  the with the EPMA, electronic microscope and ICP methods and  numeric modeling of the mass transfer accounting the melt fluid reactions with peridotites</p><p>The decompression melting processes  in peridotites beneath Avachinsky volcano (Kamchatka) are associated with seismic events. After the reactions with the Si, Ca, Na, K  from partial  melts associated  with  the  subduction related fluids the spinel and orthopyroxene were melted and essentially clinopyroxene veins were formed. Secondary crystals growth in the mantle xenoliths (with melt and fluid inclusions) are associated possibly with  the fluids appeared  due to retrograde boiling of the magma chamber beneath the volcano.</p><p>The processes of sublimation and recrystallization of  Avacha harzburgites was investigated at the facility in the Institute of  Nuclear Physics (Novosibirsk, Russia), which generates high-density electron beams and makes it possible to obtain boiling ultrabasic and basic liquids and condensates of magmatic gas on the surface of  harzburgite.</p><p>Results of  experiments provides a satisfactory explanation for the observed local heterophase alterations within ultramafic rocks that have experienced multistage deformation beneath volcanoes of the Kamchatka volcanic front.</p><p>Mathematical model of convective heating and metasomatic reactions in harzburgites were modeled using the  Selector PC thermodynamic software. The obtained virtual dynamic patterns of metasomatic zoning across the mantle wedge show   how   composition   variations   of   fluids   and  PT  conditions   at   their   sources   influence   the   facies   of   metasomatized   mantle   wedge harzburgite.   Such processes are apparently common to seismically  deformed   permeable   lithosphere   above   magma   reservoirs.  </p><p>There are two regions fluid filtration conditions under the Avachinsky volcano which are regulated by the tectonic conditions. The lower field where compression conditions prevail. And the upper field, where the prevailing tensile conditions and intense seismic destruction of the rocks of the crust and upper mantle. The heat flux distribution shows the manifestation of the convective heating mechanism in the earth's crust over the most permeable fault zones.</p><p>The study of the composition of the gas phases and melt inclusions suggests that the partial melting of metasomatized ultrabasites occurs in the range of 1150 ° C <T <1200 ° C.</p><p>In accord with the composition of the glassy phase in the melt inclusions of spinel crystals, the harzburgite metasomatism in the local melting sites is associated with brine melts that bringing Ca, K, Na, Si. C. The work was financially supported by the Russian Foundation for Basic Research, Grants No. 16-29-15131, 16-01-00729.</p><p>References</p><p>Arai S., Ishimaru S. Insights into Petrologycal Characteristics of the Lithosphere Mantle Wedge beneath Arcs through Peridotite Xenoliths: a Review.// J. Petrol., 2008. V.49(4), 359-395.</p><p>Tomilenko A.A., Kovyazin S.V., Sharapov V.N., Timina T.Yu., Kuzmin D.V. Metasomatic recrystallization and melting of ultrabasic rocks of mantle wedge beneath Avacha Volcano, Kamchatka // ACROFI III and TBG XIV Abstracts Volume / SB RAS IGM, Novosibirsk: Publishing House of SB RAS, 2010, p. 248-249.</p>

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