Petrology最新文献

{"title":"The Origin of Olivine Basalts from Medvezhya Mount (Avachinsky Group of Volcanoes, Kamchatka): The Evidence for Assimilation of Sulfide-Bearing Cumulates","authors":"D. P. Savelyev,&nbsp;N. V. Gorbach,&nbsp;M. V. Portnyagin,&nbsp;V. D. Shcherbakov","doi":"10.1134/S0869591123030074","DOIUrl":"10.1134/S0869591123030074","url":null,"abstract":"<div><p>The role and conditions of liquid immiscibility or crystallization of sulfide phase during evolution of subduction-related magmas remains a debated topic, which bears relevance to the genesis of porphyry copper deposits and evolution of the continental crust. We studied rare volcanic rocks with inclusions of magmatic sulfides in olivine—the basalts of Medvezhya Mount in the Avachinsky group of volcanoes. The rocks belong to primitive (Mg# = 66 mol %) middle-K island-arc olivine basalts. Olivine with normal zoning predominates (~98%) among phenocrysts. The olivine compositions are typical for Kamchatka basalts, except for an unusual trend of increase of MnO content from 0.20 to 0.55 wt % and decrease of Fe/Mn from 60 to 35 with a change of olivine composition from <i>Fo</i>_87.8 to <i>Fo</i>_78.2. Olivine of this group contains numerous inclusions of spinel-group minerals varying in composition from chromium spinel to magnesian magnetite. Olivine phenocrysts with sulfide inclusions are characterized by the absence of or weak reverse zoning and reduced contents of Ca, Ni, Mn, Cr, and Al. The estimated crystallization temperatures are 1036–1241°C for olivine of the prevailing type and 1010–1062°C for sulfide-bearing olivine. The data suggest that crystallization of the main olivine population occurred under relatively shallow conditions and was accompanied by strong magma oxidation. On the contrary, the zoning pattern and compositional features of sulfide-bearing olivine suggest its xenogenic origin and the probable crystallization under deep-crustal conditions from low-temperature water-rich and/or low-Ca magmas. The results obtained confirm the possibility of saturation of oxidized island-arc magmas with sulfide phase at lower crustal conditions, but show that this process is rare and not typical for low-pressure crystallization stage.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5086054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Conditions and Magmas Sources of the Summit and Flank Eruptions of Klyuchevskoy Volcano in 2020–2021: Isotope (Sr–Nd–Pb–O)-geochemical data","authors":"R. I. Cherkashin,&nbsp;O. V. Bergal-Kuvikas,&nbsp;A. V. Chugaev,&nbsp;Yu. O. Larionova,&nbsp;I. N. Bindeman,&nbsp;A. L. Khomchanovsky,&nbsp;E. Yu. Plutakhina","doi":"10.1134/S0869591123030037","DOIUrl":"10.1134/S0869591123030037","url":null,"abstract":"<div><p>In 2021, a unique event occurred on Klyuchevskoy volcano (Kamchatka). After over 30-year prevalence of summit eruptions, a flank vent was formed. It was named after the Corresponding Member of the USSR Academy of Sciences G.S. Gorshkov. The eruption began immediately after the end of the summit crater activation in 2020–2021 at an altitude of 2850 m in the northwestern part of the volcano, where manifestations of flank volcanism were not observed earlier. This paper presents geochemical and isotopic Sr–Nd–Pb–O data on lavas of the summit and flank eruptions of Klyuchevskoy volcano in 2020–2021. A comparative petrographic analysis was carried out and the chemical composition of the <i>Ol</i>, <i>Cpx</i>, and <i>Pl</i> phenocrysts in these lavas was analyzed. The lavas of both eruptions are alumina andesitic basalts of normal alkalinity. Variations of major oxides in the lavas of the summit eruption and G.S. Gorshkov vent are SiO₂ 53.1–53.2 wt % and 51.6–53.2 wt %, MgO 5.6 wt % and 5.5–6.0 wt %; respectively. Temperature and pressure estimates showed that plagioclase crystallization occurred at 1210–1118°С and 12.3–3.6 kbar in lavas of the summit eruption and at 1203–1119°С and 9.0–3.3 kbar in lavas of the flank vent. The contents of major elements, similar conditions of plagioclase generations and compositional variations of <i>Ol</i>, <i>Cpx</i>, and <i>Pl</i> phenocrysts in the lavas of both eruptions indicate a genetic relationship of the magmas that fed the summit and flank eruptions. The lavas of the 2016 and 2020–2021 summit eruptions, as well as the lavas of the previous summit eruptions of Klyuchevskoy volcano are characterized by the persistent Sr–Nd–Pb isotopic characteristics: ⁸⁷Sr/⁸⁶Sr = 0.703625–0.703626, ¹⁴³Nd/¹⁴⁴Nd = 0.513085–0.513102, ²⁰⁶Pb/²⁰⁴Pb = 18.3148–18.3179. Isotopic ratios ²⁰⁷Pb/²⁰⁴Pb (15.5022–15.5107) and ²⁰⁸Pb/²⁰⁴Pb (37.9597–38.0143) are significantly higher for the lavas of the last summit and flank eruptions than for all Klyuchevskoy lavas of the past eruptions, which indicates more complex magma evolution at crustal levels. The values of δ¹⁸O = 6.49–7.39‰ (SMOW)-in the lavas of the considered eruptions are consistent with previously published data on Klyuchevskoy volcano. The lavas of the Gorshkov vent are enriched with Ba, Zr, Sr and other incompatible elements at constant MgO values in comparison with the lavas of the last summit eruptions, which points to the different evolutionary paths of their magmas. Sharply increased values of the ⁸⁷Sr/⁸⁶Sr ratio (0.703673–0.703743) in the lavas of the G.S. Gorshkov vent, which were not previously observed in the lavas of Klyuchevskoy volcano, testify to the intense crustal assimilation of initial melts in the northwestern part of the volcano.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5088123","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sulfide Mineralization in Pyrometamorphosed Upper Crustal Xenoliths, Bezymianny Volcano, Kamchatka","authors":"V. O. Davydova,&nbsp;V. D. Shcherbakov,&nbsp;N. A. Nekrylov,&nbsp;P. Yu. Plechov,&nbsp;V. O. Yapaskurt","doi":"10.1134/S0869591123030049","DOIUrl":"10.1134/S0869591123030049","url":null,"abstract":"<div><p>Bezymianny volcano eruptions transport numerous xenoliths to the surface. Crustal xenoliths contain unique information about the crust structure and composition of crustal rocks located around the active magmatic system. We describe the chemical and mineral composition of upper crustal xenoliths that pyrometamorphosed (recrystallized and partially melted) in the Bezymianny shallow chamber. We reconstructed protoliths and hydrothermal processes for several rocks, which were previously altered, based on pre-pyrometamorhic relics (primary igneous associations in some xenoliths and rare hydrothermal relics). Moderate-K andesites, basaltic andesites, and basalts of Kamen and Bezymianny volcanoes dominate among the xenoliths. During pyrometamorphism, a microgranoblastic assemblage composed of homogenous pyroxenes, plagioclase, Fe-Ti oxides, and interstitial glass is formed in these xenoliths. Less common xenoliths are presented by high-K basaltic trachyandesite (plateau basalt from the basement of the Klyuchevskaya group of volcanoes). Quartz–carbonate–sulfide mineralization is present in some of them, which formed prior to xenolith entrapment and pyrometamorphism. When xenoliths were entrapped by magma, recrystallization of hydrothermally altered rock produced Fe-wollastonite–hedenbergite association (in some cases with garnet), untypical for Bezymianny. Some of these xenoliths have extremely high copper content (up to 1500 ppm).</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5088124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Subduction and Oceanic Magmatism Records in Plutonic Rocks of the Kamchatsky Mys Ophiolite, Eastern Kamchatka","authors":"B. A. Bazylev,&nbsp;M. V. Portnyagin,&nbsp;D. P. Savelyev,&nbsp;G. V. Ledneva,&nbsp;N. N. Kononkova","doi":"10.1134/S0869591123030025","DOIUrl":"10.1134/S0869591123030025","url":null,"abstract":"<p>The paper presents petrographic, mineralogical, and geochemical data on dunites, pyroxenites, peridotites, and gabbroids of the Kamchatsky Mys ophiolite. These data were acquired to distinguish cogenetic assemblages of igneous rocks, gain an insight into their geodynamic settings, and test various criteria of genetic links between the different magmatic rocks of ophiolites. The ultramafic and mafic rocks are shown to belong to two series, which differ in the compositions of the primary minerals, bulk rocks, and estimated trapped melts. The rocks of these series are found out to have been produced by geochemically different melts in different geodynamic settings, and during different episodes of mantle magmatism. The rocks of the high-Ti series (gabbro of the Olenegorsk massif, dunite and melanogabbro xenoliths in them, and vein gabbro in these xenoliths) crystallized from N-MORB melts in an oceanic spreading center. The rocks of the low-Ti series (dunite, pyroxenite, and gabbro veins in the residual spinel peridotites of the Mount Soldatskaya massif, as well as pyroxenite, peridotite, and gabbro alluvium and diluvium in the central and western parts of the peninsula) crystallized from water-rich boninite melts in relation to initial subduction magmatism. Taken into account the absence of boninite lavas from the Kamchatsky Mys ophiolite, the plutonic ultramafic rocks (including the rocks of the veins) might be the only evidence of subduction boninitic magmatism in the ophiolites. It was demonstrated that conclusions about the geodynamic settings of plutonic ultramafic and mafic rocks and recognition of cogenetic relations of these rocks with spatially associated basalts are more reliable when derived from the compositions of the trapped melts, which are estimated from their bulk geochemistry and primary mineral compositions, than when they are based on the mineral compositions only.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5087076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Magmatism in Kamchatka and the Kurile Islands","authors":"","doi":"10.1134/S0869591123030086","DOIUrl":"10.1134/S0869591123030086","url":null,"abstract":"","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"5088963","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Compositions of Kimberlite Melts: A Review of Melt Inclusions in Kimberlite Minerals","authors":"A. V. Golovin,&nbsp;V. S. Kamenetsky","doi":"10.1134/S0869591123020030","DOIUrl":"10.1134/S0869591123020030","url":null,"abstract":"<p>The paper presents a comprehensive review of currently available data on melt inclusions entrapped in minerals of kimberlites of different age and different provenance in ancient cratons. The crystallized melt inclusions represent snapshots of kimberlite melts at different stages of their evolution. All of the inclusions are completely crystallized and consist of daughter minerals and shrinkage bubbles, which sometimes contain low-density CO₂, but no aqueous fluids and quenched silicate glasses have been found so far. Although more than 60 mineral species have been identified among the daughter phases in the inclusions, all inclusions hosted in various minerals from different kimberlites have closely similar or even identical composition. The daughter minerals are various Na–K–Ca, Na–Ca, Na–Mg, K–Ca, Ca–Mg, Ca, Mg, and Na carbonates; Na–Mg and Na carbonates with additional anions Cl^–, <span>({text{SO}}_{4}^{{2 - }})</span>, and <span>(text{PO}_{4}^{3 - })</span>; and alkali sulfates, chlorides, phosphates, sulfides, oxides, and silicates. Alkali carbonates, sulfates, and chlorides are usually absent from among the groundmass phases of most kimberlites sampled worldwide, except the Udachnaya-East kimberlite in Siberia. However, this mineral assemblage, in association with such widespread kimberlite minerals as olivine, micas, monticellite, spinel-group minerals, perovskite, rutile, ilmenite, calcite, and dolomite, is common in the crystallized melt inclusions in all studied kimberlites. Carbonates (~30 to 85 vol %) always dominate over silicates (no more than 18 vol %) in all inclusions. All inclusions also contain variable (2 to 55 vol %.) amounts of chlorides (halite and sylvite). In cases where the abundance of carbonates is relatively low (30–50 vol %), the other major phases within inclusions are chlorides (18–55 vol %) rather than daughter silicates, as could be expected based on the traditional paradigm of the silicate composition of kimberlite melts. Published data on melt inclusions in the kimberlite minerals strongly imply that parental kimberlite melts were generated and further evolved within the Na₂O–K₂O–CaO–MgO–CO₂–Cl system, that is, they were alkali-rich carbonate/carbonate–chloride liquids. According to various estimates, SiO₂ content in kimberlite melts could have varied during different stages of their evolution from a few to 19 wt %. Clearly, kimberlite bodies are altered in the crust via interaction with meteoric and/or connate waters, resulting in serpentinization of kimberlite olivine and dissolution of many bona fide magmatic minerals, such as alkali carbonates, sulfates, and chlorides. In the traditional approach to studying kimberlites, the role of such components as Na₂O, CO₂, Cl, and to a lesser extent K₂O, S, and F in the petrogenesis of kimberlite magmas and rocks have been largely underestimated, while the roles of o","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4618789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Variations in Trace Element and Isotope Composition of Neoarchean Mafic Granulites of the Southwest Siberian Craton: a Consequence of Various Mantle Sources or Crustal Contamination","authors":"O. M. Turkina","doi":"10.1134/S0869591123020066","DOIUrl":"10.1134/S0869591123020066","url":null,"abstract":"<div><p>The paper presents geochemical and isotopic characteristics of Neoarchean (2.7–2.66 Ga) mafic granulites of the Sharyzhalgay uplift in the southwestern Siberian craton. Mafic and predominant felsic granulites compose fragments of the metamorphic complex among the Neoarchean and Paleoproterozoic granitoids. The mafic granulites are characterized by the mineral association <i>Cpx + Pl ± Hbl ± Opx ± Qz</i> and include two types with different major and immobile trace element contents. The dominant rocks of the first type have a wide range of Mg# and concentrations of TiO₂ and immobile trace elements (REE, Zr, Nb), and mainly positive ε_Nd(Т) values. The first type of mafic granulites show elevated (La/Sm)_n and enrichment in Th and LREE relative to Nb, which is typical of subduction-related or crustally contaminated basalts. The absence of negative correlation between (La/Sm)_n and ε_Nd(Т) and a clear positive correlation of TiO₂ with Nb testify against the effect of crustal contamination on the composition of the mafic granulites. The magmatic protoliths of the first type of mafic granulites are suggested to form by the melting of depleted peridotites of the subcontinental lithospheric mantle modified by melts derived from basalts or terrigenous sediments of the subducting plate. Mafic granulites of the second type have a narrower range of Mg#, TiO₂ content, positive ε_Nd(Т), flat rare earth patterns and no subduction signatures, which indicates an asthenospheric depleted mantle source. Mafic granulites contaminated by the Paleoarchean crust are characterized by increased (La/Sm)_n, depletion in Nb relative to Th and LREE, and negative ε_Nd(Т) values. Post-magmatic influence of granitoids leads to the enrichment of mafic granulites in biotite and apatite, an increase in concentrations of K₂O, P₂O₅, a significant enrichment in Zr, Nb, Th, LREE, and negative ε_Nd(Т) values. The difference between mafic granulites of the first and second types is not related to crustal contamination, but is caused by melting of two types of sources: asthenospheric and subcontinental lithospheric mantle. The subcontinental lithospheric mantle of the Irkut block was isotopically depleted at the Neoarchean time (∼2.7 Ga), and its enrichment in incompatible trace elements was likely caused by felsic melts generated from the rocks of subducting plate immediately prior to mafic magmatism.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4615613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Highly Fractionated Granites of the Raumid Massif (S. Pamir): Oxygen Isotope and Geochemical Study","authors":"E. O. Dubinina,&nbsp;A. S. Avdeenko,&nbsp;V. N. Volkov,&nbsp;S. A. Kossova,&nbsp;E. V. Kovalchuk","doi":"10.1134/S0869591123020029","DOIUrl":"10.1134/S0869591123020029","url":null,"abstract":"<div><p>The processes of crystallization differentiation, retrograde isotopic exchange, and autometamorphism are considered with reference to the Eocene granites of the Raumid massif, which consists of eight intrusive phases and serves as an example of a “natural laboratory”. The work is based on oxygen isotope, petrographic, and geochemical study of representative samples from each intrusive phase of the massif. The isotopic and geochemical studies were carried out for all rock-forming minerals (<i>Qz</i>, <i>Pl</i>, <i>Kfs</i>, <i>Bt</i>) and their altered varieties. Based on geochemical features, the Raumid granites correspond both to A-type granites and to highly fractionated I-type granites. Our results show that the rocks of the Raumid massif are not the geochemical analog of the Eocene granitoids from the Qiangtang terrane of the Central Tibet or the Vanj complex, as it previously assumed (Chapman et al., 2018). We estimated that differentiation of felsic melts of the Raumid pluton occurred at <i>T</i> = 750–800°C, and <i>P</i> = 4.5–7.8 kbar and was mainly controlled by Pl crystallization. The melts were intruded into the hypabyssal zone in at least two stages: early (γ1–γ3) and late (γ4–γ8), although it is possible that the rocks of the γ7 and γ8 phases formed an additional separate stage. The closure temperature of the oxygen isotopic system of quartz (<i>T</i>_Qz) ranges from 420 to 610°C. The effect of the multiple intrusions of the melts on the T_Qz and apparent cooling rates is considered. The study of altered and unaltered minerals showed that autometamorphism partially overlapped with the retrograde oxygen isotope exchange in the cooling rock. The modelled δ¹⁸О values during <i>Pl</i> and <i>Kfs</i> alteration describes well the observed isotope data when the crystallization takes place at limited content of water fluid (W/M = 0.3–0.05) which could release during the Raumid’s magmas crystallization.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4903573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Native Iron in Siberian Traps","authors":"M. D. Tomshin,&nbsp;A. G. Kopylova,&nbsp;A. E. Vasilyeva","doi":"10.1134/S0869591123020054","DOIUrl":"10.1134/S0869591123020054","url":null,"abstract":"<p>The study of trap intrusions with a large-scale occurrence of native iron allowed us to identify general features in their composition and origin. Intrusive bodies are weakly differentiated and have similar structure and mineralogical, petrochemical and geochemical composition. Two associations of rock-forming minerals were found in all studied bodies: early deep-seated (pre-chamber) and intra-chamber. Native iron forms nodular segregations, with a subordinate amount of cohenite, troilite and magnetite–wüstite. Metallic iron can accumulate Ni, Co, Au, and PGE. Their content in metal increases by hundreds or even thousands of times compared to host silicate rock. The formation of native iron is based on the fluid-magmatic interaction between magma and reducing components of the fluid, mainly of methane–hydrogen composition. As a result, an initially homogeneous basalt liquid is dispersed into silicate and metallic components. In the course of transportation, finely dispersed iron phases form droplet-liquid segregations with a monomolecular gas layer on their surface, thus preventing enlargement of metallic droplets. In the hypabyssal chamber, magma, including metallic spherules, is degassed, and droplets are merged to form nodular segregations of native iron.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4615614","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Moissanite in Rocks of the Bobruisk Basement Inlier, Belarusian Crystalline Massif, East European Craton","authors":"V. I. Levitskiy,&nbsp;I. V. Levitskiy,&nbsp;L. A. Pavlova,&nbsp;M. V. Lukashova","doi":"10.1134/S0869591123020042","DOIUrl":"10.1134/S0869591123020042","url":null,"abstract":"<p>A large range of minerals, native, intermetallic, and amorphous compounds containing K, Na, Fe, Mn, Ca, Ba, Sr, Cu, Pb, Co, Ni, Sn, Zn, Al, Ce, Nd, La, Pr, Sm, Y, Yb, Nb, Hf, W, Mo, Zr, Cr, V, Ag, Ti, Si, As, P, Bi, O, H, F, Cl, S, Se, C, B, N, and F has been identified in rocks from the Bobruisk basement inlier of the Belarusian crystalline massif in the western part of the East European craton. One of the identified phases was moissanite, which occurs as anhedral and subhedral grains up to 1.5 mm and is the 6H hexagonal polytype. One of the moissanite grains contained mineral inclusions inherent in meteorites: sinoite (Si₂N₂O), xifengite (Si₅Fe₃), and awaruite (Ni₃Fe). The moissanite and native, intermetallic, and amorphous phases associated with it occur as rare disseminated grains of various size in rocks of three rock complexes in the basement of the Bobruisk inlier. This indicates that the mineralization is overprinted. The whole set of crystalline and amorphous phases found in association with moissanite is proposed to be named <i>bobruiskites</i>. The minerals were most probably formed by an meteorite impact on rocks of the East European craton.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":null,"pages":null},"PeriodicalIF":1.5,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"4615615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}