Petrology最新文献

{"title":"The Evolution of Sulfide Melts as a Key Factor in the Distribution and Concentration of Platinum-Group Elements in Norilsk Ores","authors":"V. D. Brovchenko","doi":"10.1134/S0869591124700322","DOIUrl":"10.1134/S0869591124700322","url":null,"abstract":"<p>The Norilsk–Talnakh magmatic sulfide Cu–Ni–PGE (platinum-group elements) deposits were formed by the accumulation of metals in immiscible sulfide melt comagmatic with the parental mafic–ultramafic magma. In this study, the main types of magmatic sulfide ores of the Norilsk–Talnakh deposits are considered as manifestations of different stages in the evolution of the initial sulfide melts. In the context of the overall evolution of Norilsk sulfide melts, the earliest ores are Cu-poor pyrrhotite ores with high concentrations of Rh and IPGE (Os, Ir, and Ru), which were discovered at the Talnakh deposit. The second stage of sulfide melt evolution was marked by the formation of most disseminated ores and Cu- and PGE-poor massive pyrrhotite ores. The massive and disseminated ores were formed independently from each other, but generally correspond to the melts with identical compositions. The only exception is low-sulfur PGE-rich ores from the Upper Gabbroid rocks of the differentiated intrusions, which were affected by wall rock assimilation and early magmatic degassing. It has been shown that the concentrations of ore components in the disseminated sulfides, which are examples of in-situ crystallized droplets of immiscible sulfide melt, vary depending on the composition and degree of fractionation of the parental silicate magma. During the final stage, the crystallization of the residual sulfide melts led to the formation of Cu-rich ores with high Pt and Pd contents. The compositions of these main ore types are compared with the compositions (including trace elements) of their base metal sulfides (BMS). All element dependencies in the massive ores follow the fractional crystallization trend of the sulfide melt. PGE in Norilsk ores are concentrated in distinct platinum-group minerals (PGM) and occur as trace elements in BMS. Rhodium and IPGE are concentrated in pyrrhotite, pentlandite, and pyrite; Pt is occasionally found in pyrite; whereas Pd is found predominantly in pentlandite. The concentration of Pd in pentlandite increases from the Cu-poor to Cu-rich ores. Based on a detailed analysis with the application of several methods, the Pd-rich pentlandite (containing 4.84 wt % Pd) from massive primary magmatic Cu-rich <i>MSS–ISS</i> ores is thought to have been formed by a high-temperature mechanism involving a reaction with sulfide melt. Using <i>X</i>-ray absorption spectroscopy (XAS), the oxidation state of Pd in pentlandite (2⁺) and its occurrence in the form of a solid solution, in which Pd apparently replaces Ni in the pentlandite structure, were identified for the first time.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 1 supplement","pages":"S1 - S75"},"PeriodicalIF":1.0,"publicationDate":"2025-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143865569","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":"Minerals of the Тochilinite–Ferrotochilinite Series from Rocks of the Urals and Trans-Urals: Мineral Аssociations, Сhemical Сomposition, and Genesis","authors":"S. V. Pribavkin,&nbsp;E. V. Pushkarev,&nbsp;I. S. Chashchukhin,&nbsp;Yu. V. Erokhin,&nbsp;A. V. Korovko","doi":"10.1134/S0869591124700358","DOIUrl":"10.1134/S0869591124700358","url":null,"abstract":"<div><p>The paper presents the results of studying the scarce iron–magnesium sulfide–hydroxides of the tochilinite–ferrotochilinite series with the ideal formula 6FeS·5Mg(OH)₂. These minerals are formed during serpentinization of ultrabasites of different nature and were described in peridotites of the Kempirsai, Khabarny, Kytlym and Uktus massifs in the Urals and the Verkhne-Iusskaya area of the Shaim petroleum region of Western Siberia. The aim of this work is to examine the poorly studied chemical composition of tochilinite, to determine its mineral associations and conditions of formation. The minerals were analyzed by optical and electron scanning microscopy, Raman and IR spectroscopy. Based on the magnesium number (<i>Х</i>_Mg), the minerals could be divided into tochilinite and ferrotochilinite. High-Mg minerals (<i>Х</i>_Mg = 0.73–0.79) are found in the Uktus massif and in the Verkhne-Iusskaya area, and low-Mg varieties (<i>Х</i>_Mg = 0.15–0.38) occur in the Khabarny and Kytlym massifs. The presence of mixed-layer phases represented by the alternation of nano-scale layers of tochilinite or ferrotochilinite with serpentine is assumed. The chromium-bearing varieties of tochilinite are noted. Mechanisms and chemical reactions leading to the formation of tochilinites during the low-temperature transformation of peridotite in the presence of water are discussed. In most cases, this is the interaction of metamorphic water with magmatic sulfides during the serpentinization of peridotite, or the influence of sedimentary or another waters containing dissolved sulfur on them. It is concluded that tochilinite served as a sulfur absorbent during early reticulate serpentinization of ultramafic rocks. Tochilinite could be used as a promising geothermometer for low-temperature ultramafic mineral assemblages.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 2","pages":"112 - 129"},"PeriodicalIF":1.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856529","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":"Evidence for Partial Melting in Mantle Xenoliths of Spinel Lherzolites of Zhokhov Island, De Long Archipelago, Eastern Arctic","authors":"S. A. Silantyev,&nbsp;D. D. Badyukov,&nbsp;A. G. Akhmetshin,&nbsp;E. A. Krasnova","doi":"10.1134/S086959112470036X","DOIUrl":"10.1134/S086959112470036X","url":null,"abstract":"<div><p>Zhokhov Island belongs to the De Long Archipelago located in the Eastern sector of the Russian continental shelf within the Arctic Basin. The island is a young volcanic center and is composed of lava flows of alkaline olivine-porphyry basalts and subordinate limburgites. The study was aimed at identifying the possible regional and geodynamic factors influencing the specifics of the partial melting and mineral transformations in mantle xenoliths of Zhokhov Island. Five xenoliths selected from alkali basalt samples on Zhokhov Island were studied using a scanning electron microscope. The data obtained allowed us to conclude that the formation of high-sodium glasses in the mantle xenoliths of Zhokhov Island is associated with the interaction between spinel lherzolites and parental melts of host olivine basalts. At the same time, high-potassium glasses inside mantle xenoliths were formed in situ during the melting of a primary potassium-bearing phase, likely phlogopite. The formation of two distinct compositionally contrasting recrystallization zones in contact between the mantle xenoliths and the host basalt is caused by the evolution of host alkaline silicate melt from sodic to potassic composition. Signs of activation of young intraplate magmatism that brought up the fragments of metasomatized shallow mantle to the surface are established over a large area of the Arctic Basin within the HALIP large igneous province.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 2","pages":"81 - 93"},"PeriodicalIF":1.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856530","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":"Experimental Study of Chemical Counterdiffusion of Major Components (SiO2, Al2O3, Na2O, CaO, MgO, and FeO) and ({text{CO}}_{3}^{{2 - }}) Anion during Interaction of Basalt and Kimberlite Melts under Upper Mantle P–T Conditions","authors":"E. S. Persikov,&nbsp;P. G. Bukhtiyarov,&nbsp;A. G. Sokol,&nbsp;A. N. Nekrasov,&nbsp;D. M. Sultanov","doi":"10.1134/S0869591124700346","DOIUrl":"10.1134/S0869591124700346","url":null,"abstract":"<p>This paper reports new experimental results on the chemical counterdiffusion of major components (SiO₂, Al₂O₃, Na₂O, CaO, MgO, and FeO) and the <span>({text{CO}}_{3}^{{2 - }})</span> anion during interaction of basalt and kimberlite melts under upper-mantle pressure. The method of diffusion couples was employed on a BARS split-sphere apparatus at 5.5 GPa and 1850°C. It was shown that the rates of chemical counterdiffusion of all major melt species (SiO₂, Al₂O₃, Na₂O, CaO, MgO, and FeO) and the <span>({text{CO}}_{3}^{{2 - }})</span> anion are almost identical during interaction of model basalt and carbonate-bearing kimberlite melts and approximately an order of magnitude higher than the diffusion rates of these components during melt interaction under moderate pressures (100 MPa). The equal diffusion rates of CaO and <span>({text{CO}}_{3}^{{2 - }})</span> indicate that molecular CaCO₃ diffusion from the kimberlitic to basaltic melt (model and natural) occurs also at the high pressure. The diffusion patterns are dramatically different during interaction of natural magnesian basalt and model kimberlite, which was observed for the interaction of these melts at moderate pressure. In addition to the molecular diffusion of CaCO₃ into the magnesian basalt, the diffusion rates of other melt species increase significantly. All diffusing components show weak exponential dependence on concentrations approaching <i>D</i>_<i>i</i> = const, similar to that observed during interaction of such melts at moderate pressures.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 2","pages":"130 - 138"},"PeriodicalIF":1.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856531","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":"Melts of Ocean Island Basalts (OIB) and Their Sources: Evidence from Melt Inclusions and Quenched Glasses of Rocks","authors":"V. B. Naumov,&nbsp;A. V. Girnis,&nbsp;V. A. Dorofeeva","doi":"10.1134/S0869591124700334","DOIUrl":"10.1134/S0869591124700334","url":null,"abstract":"<p>In this paper, we examine the compositions of basaltic melts from ocean islands using our regularly updated database of analyses of melt inclusions in minerals and glasses of igneous rocks. Mean concentrations of major, trace, and volatile components in melts were calculated for the global dataset (22 550 analyses from 33 island systems) and for the most extensively studied complexes (Iceland, Hawaii, Canaries, Galapagos, and Reunion). It was found that the mean contents of most elements fall between the mean compositions of magmas from mid-ocean ridges (most depleted) and intraplate continental complexes (most enriched). Variations of element ratios in particular complexes were considered in detail, and it was found that they can be described by mixing magmas from a depleted source and variably enriched materials. The abundances of trace elements in the supposed mantle sources were estimated. The depleted source is most clearly manifested in Iceland and is almost identical to the depleted mantle the melting of which produces mid-ocean ridge basalts.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 2","pages":"94 - 111"},"PeriodicalIF":1.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856528","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":"Geochemical Characterization, Tectonic Setting, and Metamorphic History of Metabasites from Jandaq Metamorphic Complex, Iran","authors":"Arefeh Heidarianmanesh,&nbsp;Seyed Mohsen Tabatabaei Manesh,&nbsp;Nargess Shirdashtzadeh,&nbsp;Farid Chemale Junior,&nbsp;O. V. Parfenova","doi":"10.1134/S0869591124700371","DOIUrl":"10.1134/S0869591124700371","url":null,"abstract":"<p>Metabasites within the Jandaq Metamorphic Complex (JMC), Iran, offer valuable insights into the region’s magmatic and metamorphic history. Whole-rock geochemical data (major, trace, and rare earth elements) coupled with Sm-Nd isotopes were used to decipher the protolith origin and tectonic setting of formation of these metabasites. Our results demonstrate a predominantly ortho-amphibolitic nature for the JMC metabasites, with igneous protoliths ranging from basalt to andesite based on geochemical discrimination diagrams (Zr versus MgO and Sm/Nd). They exhibit geochemical affinities closer to enriched mid-oceanic ridge basalts (E-MORB) rather than normal MORB, implying a nascent oceanic basin within an intracontinental extensional setting. Trace element signatures (LILE enrichment, HFSE depletion) suggest a metasomatized subcontinental lithospheric mantle (SCLM) or a metasomatized lithospheric mantle beneath the oceanic crust as the parental magma source. Sm-Nd isotopic data suggest a potential plume source for the protoliths. These rocks were metamorphosed further by at least three metamorphic events: M1 (regional metamorphism, Barrovian-type; 616–687°C, 8–11 kbar), M2 (a brittle deformation event), and a later retrograde metamorphism (M3). These findings provide a comprehensive understanding of the geochemical characteristics, tectonic setting, and metamorphic evolution of JMC metabasites, shedding light on the geological history of the Jandaq region as a Paleo-Tethyan remnant.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 2","pages":"139 - 161"},"PeriodicalIF":1.0,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856581","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":"Petrogenesis and Sources for Rocks of the Rare-Metal Alkaline Burpalа Intrusion (Northern Baikal Region)","authors":"A. G. Doroshkevich,&nbsp;V. M. Savatenkov,&nbsp;A. V. Malyutina,&nbsp;I. A. Izbrodin,&nbsp;I. R. Prokopiev,&nbsp;A. E. Starikova,&nbsp;T. A. Radomskaya","doi":"10.1134/S0869591124700280","DOIUrl":"10.1134/S0869591124700280","url":null,"abstract":"<div><p>The paper reports the results of petrologic and geochemical study of the Burpala alkaline intrusion composed of quartz syenites, alkaline and nepheline syenites, including ore-bearing varieties, which is a part of the Late Paleozoic North Baikal Alkaline Province. Chemically, the studied rocks belong to foid monzosyenites, foid syenites and syenites, ranging from agpaitic to miascitic varieties. Close Sr-Nd isotopic characteristics and geochemical patterns confirm the syngenetic nature of magmas that produced nepheline, alkaline, and quartz syenites. A negative Eu anomaly in the REE patterns and sufficiently low Mg# of rocks testify in favor of a prolonged fractional crystallization of rocks from an alkaline-basic melt. Sr-Nd-Pb isotopic and geochemical characteristics of rocks of the Burpala intrusion reflect the predominance of metasomatized lithospheric mantle in their source. The formation of the rocks of the intrusion, according to the trace element and isotopic data, was complicated by the upper crustal assimilation, which likely determined the genetic relationship between nepheline and quartz syenites within the intrusion.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 1","pages":"40 - 61"},"PeriodicalIF":1.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769906","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":"Possibility of Discriminating between Postcollisional and Intraplate A-Type Granitoids Based on Geochemical Data","authors":"S. D. Velikoslavinskii,&nbsp;A. B. Kotov,&nbsp;E. V. Tolmacheva,&nbsp;D. P. Krylov,&nbsp;T. M. Skovitina","doi":"10.1134/S0869591124700310","DOIUrl":"10.1134/S0869591124700310","url":null,"abstract":"<p>A diagram is proposed for discriminating between at least some A-type intraplate and postcollisional granitoids. The diagram is based on data of the discriminant analysis of geochemically similar Phanerozoic A-type granitoids and is demonstrated to be able to identify the types not only of Phanerozoic but also of Precambrian A-type granitoids.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 1","pages":"72 - 80"},"PeriodicalIF":1.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769874","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":"Origin of the Earth’s First Felsic Crust: A Hydrogen Perspective?","authors":"L. Y. Aranovich,&nbsp;E. S. Persikov,&nbsp;P. G. Bukhtiyarov,&nbsp;A. N. Koshlyakova,&nbsp;N. M. Lebedeva","doi":"10.1134/S0869591124700279","DOIUrl":"10.1134/S0869591124700279","url":null,"abstract":"<p>The paper presents experimental data on melting model compositions of basaltic komatiite (<i>BK</i>) and enstatite chondrite (<i>ECH</i>) at a temperature of <i>T</i> = 1300°C and hydrogen pressure <span>({{P}_{{{{{text{H}}}_{{text{2}}}}}}})</span> = 100 MPa. The experiments modeled interaction between the magma ocean and the early Earth’s hydrogen atmosphere. The experimental products consist of silicate glass (quenched melts), which is notably depleted in FeO but enriched in lithophile oxides and H₂O, and iron with minor Si and O admixtures. The equilibrium oxygen fugacity in the experimental runs was approximately two logarithmic units below the Fe−FeO buffer. Calculation of the fractional crystallization of the melts indicates that the complete crystallization products are granodiorite, which consists of two feldspars, clinopyroxene, and quartz with a minor amount of black mica (for the starting composition obtained in the run with <i>BK</i>), or quartz−two feldspars granite with minor amounts of biotite and muscovite (for the starting composition obtained in the run with <i>ECH</i>). Crystallization of zircon from the <i>ECH</i> melt might occur at <i>T</i> = 730−750°C. Our proposed model is the first that explains generation of melts enriched in SiO₂ and H₂O by internal processes of planetary evolution and does not invoke pre-hydrated upper crust for generating the Earth’s first felsic material.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 1","pages":"62 - 71"},"PeriodicalIF":1.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769875","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":"Carbonation of Serpentinites of the Mid-Atlantic Ridge: 2. Evolution of Chemical and Isotopic (δ18O, δ13С, Rb, Sr, Sm, Nd) Compositions during Exhumation of Abyssal Peridotites","authors":"E. A. Krasnova,&nbsp;S. A. Silantyev,&nbsp;V. V. Shabykova,&nbsp;A. S. Gryaznova","doi":"10.1134/S0869591124700292","DOIUrl":"10.1134/S0869591124700292","url":null,"abstract":"<div><p>Carbonate minerals in oceanic crust are formed through CO₂ interaction with silicate minerals of ultramafic and mafic rocks. Carbonation leads to the generation of numerous carbonate veins, filling interstices in the rock matrix and producing partially and/or completely carbonated rocks that compose the protolith of slow-spreading mid-ocean ridges and are present in ophiolite complexes. Silantyev et al. (2023) proposed a conceptual model of the main stages in the formation of carbonated serpentinites in different segments of the Mid-Atlantic Ridge. In this study, we examined isotope variations (δ¹⁸O, δ¹³С, Rb, Sr, Sm, Nd) in the previously studied carbonated ultramafic rocks from oceanic core complexes of the slow-spreading mid-oceanic ridge. The carbon and oxygen isotope compositions obtained in our study are well consistent with results of our previous studies and make it possible to quantify the duration and spatial position of sea fluid interaction with serpentinites of different segments of the Mid-Atlatnic Ridge in the oceanic crust sequence. Peridotite groups previously distinguished based on the mineral and petrographic features are well consistent with relations of obtained parameters or with water/rock ratio calculated using Sr-Nd isotope systematics, and reflect the sequence of carbonation stages in the ultramafic protolith of oceanic crust and duration of its residence on the seafloor. Our results indicate that the oceanic core complexes containing the studied rocks were exhumed to the seafloor surface during different time periods.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 1","pages":"23 - 39"},"PeriodicalIF":1.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769876","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}