Petrology最新文献

{"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}

{"title":"Late Pleistocene Mafic Magmatism and Its Relation to Large Caldera-Forming Eruptions on Iturup Island: An Example of Klumba Volcano, Kuril Islands","authors":"T. Yu. Timina,&nbsp;S. Z. Smirnov,&nbsp;D. V. Kuzmin,&nbsp;A. A. Kotov,&nbsp;A. V. Rybin,&nbsp;V. A. Danilovsky,&nbsp;A. E. Izokh","doi":"10.1134/S0869591124700309","DOIUrl":"10.1134/S0869591124700309","url":null,"abstract":"<p>Klumba basaltic andesite volcano is the only postcaldera volcano in the eruptive center of one of the most powerful explosive eruptions that occurred at the end of the Late Pleistocene in the Great Kuril Arc (GKA) and formed a thick sequence of dacitic pumice tuffs on the Vetrovoy Isthmus on Iturup Island. A detailed study of the mineralogy of the basaltic andesites of Klumba volcano and olivine-hosted fluid and melt inclusions showed that the feeding magma evolved within the arc crust at depths between 15.5 and 7 km and was related to Mg-rich (up to 9.8 wt % MgO), low-K and low-Al basaltic andesite melts that initially contained about 5–6 wt % H₂O. Olivine and Cr–Al spinel were the first to crystallize in the magma and later were joined by plagioclase and pyroxenes. The phenocrysts crystallized at temperatures of about ~1000–1200°C. The melt was saturated with CO₂ fluid with minor amounts of SO₂. Pleistocene basaltic andesitic magmatism in the central part of Iturup Island was predominantly intrusive and resulted in the formation of a large transcrustal magmatic system (TCMS), which could include the dacitic chamber that fed the explosive eruption of the Vetrovoy Isthmus. The plumbing system of Klumba volcano is considered to be a part of this TCMS, which was intermittently recharged by variously differentiated basaltic andesite magmas. It is assumed that such systems may have developed on the scale of the whole island. The duration of the processes and the amount of intruded magma may have been sufficient to cause partial melting in the upper parts of the island-arc crust and to form magma reservoirs of powerful explosive caldera-forming eruptions.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"33 1","pages":"1 - 22"},"PeriodicalIF":1.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143769907","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":"Granitoid Intrusions at the Periphery of the Kursk Block as Part of a Paleoproterozoic Silicic Large Igneous Province in Eastern Sarmatia","authors":"K. A. Savko,&nbsp;A. V. Samsonov,&nbsp;E. Kh. Korish,&nbsp;A. N. Larionov,&nbsp;E. B. Salnikova,&nbsp;A. A. Ivanova,&nbsp;N. S. Bazikov,&nbsp;S. V. Tsybulyaev,&nbsp;M. V. Chervyakovskaya","doi":"10.1134/S0869591124700218","DOIUrl":"10.1134/S0869591124700218","url":null,"abstract":"<p>Paleoproterozoic diorite–granodiorite magmatic rocks dated at 2.04–2.08 Ga are widespread at the eastern border of the Archean Kursk block of Sarmatia. The granitoids of the intrusive massifs are metaluminous calc-alkaline I-type rocks enriched in incompatible elements (LILE and LREE), with negative Ti, P, and Nb anomalies. The rocks show widely varying negative ε_NdT values, their zircons have broadly ranging ε_HfT values, and the melts were derived within a broad range of depths from heterogeneous Archean lower crustal mafic sources. The diorites were melted from the least radiogenic ancient crustal sources. The granodiorites were derived from Paleo- and Mesoarchean and more juvenile Neoarchean sources. The intense 2.06-Ga magmatism was triggered by the upwelling of the asthenospheric mantle during the break-up of subducted oceanic slab due to low-angle subduction. The break of the slab and the mafic underplating led to the crustal melting of the upper slab, which consisted of Archean and Paleoproterozoic crustal fragments of different age that had been welded as a result of earlier accretion. Diorite−granodiorite magmas were generated in chambers at different depth in the ancient Archean crust at the periphery of Kursk block, with the incorporation of Paleoproterozoic lithospheric fragments of the Eastern Sarmatian orogen into the melting sources.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"32 6","pages":"719 - 771"},"PeriodicalIF":1.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778119","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":"Potassium Alkaline Volcanism of Alaid Volcano, Kuril Islands: the Role of Subduction Melange in Magma Genesis","authors":"Yu. A. Martynov,&nbsp;V. A. Rashidov,&nbsp;S. I. Dril","doi":"10.1134/S0869591124700231","DOIUrl":"10.1134/S0869591124700231","url":null,"abstract":"<div><p>New major-, trace-element and Sr-Nd-Pb isotope data are presented on the Holocene high-potassium basic lavas of Alaid volcano, which is located in the north of the Kuril island arc, in the junction zone with the Kamchatka volcanic segment. According to the petrochemical criteria, two groups of coeval rocks are distinguished: Ne-normative shoshonites and high-potassium subalkaline basalts, which have many similar geochemical characteristics. Chondrite-normalized REE distribution patterns show LREE enrichment, with flat HREE pattern, and the absence of Eu and Ce anomalies. MORB-normalized incompatible element patterns show LILE enrichment and a well-defined negative Ta–Nb–Ti anomaly typical of suprasubduction volcanics. The high K₂O/Rb and Rb/Sr ratios indicate the presence of biotite and amphibole in the magmatic source, while the low Sr/Y ratios and flat MREE and HREE distribution patterns indicate the absence of residual garnet. Significant variations in the contents of major- and trace elements at similar MgO concentrations indicate a heterogeneous magma source, while linear mixing trends in isotope and discrimination diagrams, as well as experimental data, suggest the involvement in magmogenesis of not only peridotite mantle, but also amphibole–clinopyroxene mineral paragenesis. An analysis of literature data shows that the manifestations of potassium alkaline magmatism in “cold” island arcs are frequently, if not always, confined to local extension zones. Since such zones are associated with the adiabatic rise of a hot and ductile asthenosphere, it can be assumed that melting involved subduction mélange, which is formed along the boundary of the slab and supra-subduction mantle and consists of hydrated fragments of ultrabasites and metamorphosed oceanic crust transformed into amphibole-bearing pyroxenites. This mechanism makes it possible to logically explain the geochemical and isotopic features of the anomalous alkaline magmatism of the Kuril island arc and the relation of its northern segment with anomalous tectonics. The results obtained may be important in discussing the genesis of potassium alkaline magmas occurred in subduction geodynamic settings.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"32 6","pages":"828 - 858"},"PeriodicalIF":1.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778258","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":"Oleg A. Bogatikov: December 15, 1934–March 1, 2022","authors":"Editorial Board","doi":"10.1134/S0869591124700267","DOIUrl":"10.1134/S0869591124700267","url":null,"abstract":"","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"32 6","pages":"717 - 718"},"PeriodicalIF":1.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778118","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":"Zircon U-Pb-Hf Isotopes and Geochemistry of Mo-bearing Granite Porphyry in the Lower Urgen Mo Deposit: Implications for the Late Mesozoic Porphyry Mo and Cu Mineralization in the Northern and Central Great Xing’an Range, NE China","authors":"Wei Xie,&nbsp;Guangliang Zhang,&nbsp;Chao Jin,&nbsp;Qingdong Zeng,&nbsp;Shouqin Wen,&nbsp;Lingli Zhou,&nbsp;Tieqiao Tang,&nbsp;Pengcheng Ma,&nbsp;Hui Wang,&nbsp;Kailun Zhang","doi":"10.1134/S0869591124700243","DOIUrl":"10.1134/S0869591124700243","url":null,"abstract":"<p>The Lower Urgen deposit is a newly discovered porphyry Mo deposit in the northern and central Great Xing’an Range. Mineralization predominantly occurs within granite porphyry, yielding a zircon U-Pb age of 142.3 ± 1.5 Ma, thereby endorsing an Early Cretaceous Mo mineralization event. Zircon ε_Hf(T) values (5.5–7.7) and T(DM2-st) (707–844 Ma) suggest that the granite porphyry originated from the partial melting of the Neoproterozoic lower crust. These granite porphyries exhibit coherent geochemical signatures with regional Late Mesozoic Mo-causative granites. Classified as highly fractionated A-type granites, they are enriched in Rb, Th, U, and K, and depleted in Ba, Sr, P, Ti, and Eu. Notably, they possess higher Rb/Sr and Rb/Ba ratios, and lower (La/Yb)_N, Eu/Eu*, LREE/HREE, K/Rb, and Zr/Hf ratios than coeval Cu-causative granites, implying the extent of fractional crystallization plays a pivotal role in determining the mineralization styles (Mo- versus Cu-dominant). Two possible tectonic models are proposed. In one model, Late Jurassic Mo- and Cu-causative granites were formed in an intra-plate extensional setting and compressional setting induced by the flat-slab subduction of the Mongol-Okhotsk Ocean (MOO) plate, respectively, while Early Cretaceous Mo-causative granites were formed in a post-collision extensional setting following the final closure of the MOO. The post-orogenic lithospheric extension model related to the closure of the MOO provides another plausible explanation for the origin of the ore-causative granites. Early Cretaceous highly fractionated A-type granites and Late Jurassic low fractionated adakitic granites represent potential targets for future exploration of Mo- and Cu-dominant porphyry deposits, respectively.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"32 6","pages":"859 - 890"},"PeriodicalIF":1.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778259","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":"Deformation and Metamorphic History of Precambrian High-Grade Rocks of Key Afer Area, Southwestern Ethiopia","authors":"Bishaw Mihret,&nbsp;Ajebush Wuletaw,&nbsp;Tarekegn Tadesse","doi":"10.1134/S0869591124700255","DOIUrl":"10.1134/S0869591124700255","url":null,"abstract":"<p>The deformation and metamorphic history of the Precambrian high-grade rocks in the Key Afer area, southwestern Ethiopia within the Mozambique belt is described. It comprises poly-deformed, metamorphosed, and migmatized rocks with intrusion of granitoids and overlain by Quaternary sediments. A combination of field litho-structural mapping, metamorphic mineral assemblages, and microstructural analysis there are three metamorphic events and four phases of ductile deformation, and one Cenozoic brittle fracture (D5) are recognized. The development of the relatively steep NNW-SSE trending S1 relict gneissic banding and the rise of pyroxene and anhydrous minerals indicate that the peak metamorphism (M1) is synchronous with D1. Subsequently, the hydration of M1 assemblages leads to the formation of amphibolite facies (M2). This is followed by the development of amphibolite facies (M2) caused by the hydration of M1 assemblages synchronous with the D2 deformation. It is defined by the major regional fabric (S2) of the area trending NW-SE, tight to isoclinal upright F2 folds, and local L2 lineation. These D2 upright folds are orthogonally superimposed by another upright F3 folds during D3 resulting in a type-I fold interference pattern. The replacement and breakdown of hornblende to epidote, biotite to chlorite, and plagioclase to sericite give a retrogressive event to greenschist facies (M3) syn-D4. It gave rise to NNE-SSW-oriented S4 mylonitic foliations associated with F4 drag folds. Both sinistral and dextral shear sense is recorded but dextral shear sense appears dominant. The fifth phase of deformation (D5) is characterized by brittle fracture and joint structures of the area with varying orientations. The three metamorphic events with deformational episodes of the study show a clockwise <i>P-T</i> path loop from burial to uplift similar to the collision-parallel shearing orogenic setting.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"32 6","pages":"891 - 909"},"PeriodicalIF":1.0,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142778260","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}