Petrology最新文献

{"title":"Crystal Size Distributions, Crystal Zoning, and Bulk Rock Geochemistry Correlation in Olivine Cumulates from the Yoko-Dovyren and Monchepluton Layered Intrusions","authors":"S. N. Sobolev, A. A. Ariskin","doi":"10.1134/S0869591126700013","DOIUrl":"10.1134/S0869591126700013","url":null,"abstract":"<p>The central point of this work is the crystal size distribution (CSD) data on primitive olivine cumulates from two large layered intrusions located in Russia: the Yoko-Dovyren massif (Northern Baikal region) and Monchepluton (Murmansk region, Kola Peninsula). Dunites, troctolites, harzburgites, and chromitites have been studied. Ninety-one crystal size distributions of olivine and chromite, acquired mostly manually in thin sections, are presented. The CSD shape tends to be loglinear, bimodal (kinked), or lognormal. Number of CSDs for the selected zone or the part of stratigraphic cumulate succession in the intrusion is enough to reveal sustainably repeating CSD patterns, which provide a clear kinetic fingerprint of a some point in the dynamic evolution of crystallizing magma bodies and protocumulate crystal mushes. The CSDs kinetic record in turn may be partly deciphered by comparing the natural CSD forms with mathematical or qualitative models of distribution formation. We used previously published models for explanation of different CSD shapes and also proposed a modified model with nonequilibrium <i>T</i>-<i>t</i> path for the origin of the primary loglinear distribution widely known in magmatic rocks. The first idea of proposed modification is simultaneous accounting in a single model experimentally known bell-shaped dependence of nucleation and growth rates on supercooling and also experimentally proved dependence of the growth rate on the grain size (proportional growth). Previous models include this effect only separately. The second idea is the dependence of the intensity of the proportional growth effect also on supercooling. To this stage of calculation the original equation is proposed. The selected model for the natural CSD pattern formation is additionally verified by studying the growth and dissolution history of individual grains, which is recorded in chemical or morphological zoning of crystals. Phosphorus and other trace element zoning of olivine was analyzed using electron microprobe mapping. Contrast BSE images were used for the observation of zonal inclusion distribution in chromite. To take into account that the most common case is the open-system behavior of magma meaning that crystals move relative to the mother liquid during crystal population formation, the additional element is required to prove the dynamic process suggested by kinetics. This element is the study of bulk geochemistry and its correlation with CSD types, which reflects how the particular area of crystal mush with specific CSD differs from its previous state and how step by step it evolves away from the initial magma. Following this, CSD and zoning data for a number of olivine-rich rock samples were correlated with the bulk chemical composition of the rocks. The last aspect of the approach described in the paper involves assessing the thermodynamic state of the initial magma and crystalline mush of the studied region of a chamber at the time of local sub","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 1","pages":"S1 - S105"},"PeriodicalIF":1.0,"publicationDate":"2026-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148552869","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":"Petrology, Geodynamics and Application of 3D Numerical Modeling for the Kara (Taimyr–Severnaya Zemlya) Orogen","authors":"V. A. Vernikovsky,&nbsp;A. E. Vernikovskaya,&nbsp;V. F. Proskurnin,&nbsp;N. Yu. Matushkin,&nbsp;O. P. Polyansky,&nbsp;A. N. Semenov","doi":"10.1134/S0869591126700104","DOIUrl":"10.1134/S0869591126700104","url":null,"abstract":"<p>We show that the Kara orogen formed due to oblique collision as evidenced by geological and paleomagnetic data. A distinct zoning in the emplacement of granitoids is noticeable – the syncollisional plutons are located in the western and central parts of the orogen, and the postcollisional ones – in the eastern part. The syncollisional granites were formed in zones of anatectic melting of crustal rocks and are located mainly in zones of amphibolite metamorphism and migmatization. The postcollisional granites form small stocks intruding the metamorphic rocks, the syncollisional granites, as well as unmetamorphosed Paleozoic cover deposits of the Central Taimyr accretionary belt. The main tectonothermal processes are explained, as well as the stages of crustal heating and the patterns in melt formation and emplacement of syncollisional and postcollisional granitoids. The transition from 2D to 3D modeling and the connection of the collision to the formation of the Siberian LIP are described.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"390 - 393"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532374","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":"The Sources of Cretaceous Magmatism in the Uda Sector of the Western Transbaikalian Rift Region Based on Geochemical and Isotopic (Sr, Nd, O, Pb) Data","authors":"A. A. Vorontsov,&nbsp;V. V. Yarmolyuk,&nbsp;S. I. Dril,&nbsp;V. M. Savatenkov,&nbsp;D. A. Lykhin,&nbsp;E. N. Federyagina,&nbsp;S. A. Sasim","doi":"10.1134/S086959112670030X","DOIUrl":"10.1134/S086959112670030X","url":null,"abstract":"<p>The Uda, Yeravna, and Zaza riftogenic depressions belong to the Uda sector, which serves as the central fragment of the Western Trans-Baikal rift zone. New Sr–Nd–Pb–O isotopic data on the Cretaceous basaltic rocks from each depression in combination with geochemical data made it possible to estimate the compositions of mantle and crustal magmas and to propose a model for their mixing.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"453 - 455"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532390","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":"Interaction of Mafic Magma and Carbon‑Bearing Sediments: Evidence from the Paleoproterozoic Onega Basin and Implications for Carbon Migration","authors":"S. Y. Chazhengina,&nbsp;V. V. Ustinova,&nbsp;A. V. Stepanova","doi":"10.1134/S0869591126700396","DOIUrl":"10.1134/S0869591126700396","url":null,"abstract":"<p>The impact of mafic magmatism on hydrocarbon systems remains debated, particularly in Precambrian settings. The results of combined field and petrological studies, carbon isotope analysis, and Raman spectroscopy for mafic sills intruded into carbon-bearing sedimentary successions in the Paleoproterozoic Onega Basin (NW Russia) provide new insights into mechanisms of carbonaceous matter (CM) migration and deposition. Greenschist facies metamorphism has negligible impact on large‑scale CM redistribution, as evidenced by the occurrence of CM‑bearing and CM‑free sills at contacts with carbon‑rich sediments under similar metamorphic conditions. Raman data indicate CM precipitation at ~400°C suggesting a hydrocarbon fluid migration during sill cooling. The carbon isotopic composition in the CM-bearing dolerites (δ¹³C = –26...–29‰) is the same as in host sediments indicating them as the main source of CM. The thin zones of the dolerites enriched in CM at the upper contact of the sills are a result of near-contact transfer during magma emplacement. The concentration of CM in the interstices in dolerites and enhance of CM content from medium-grained dolerites to gabbro-pegmatites in the central parts of the sills suggest the low miscibility of CM‑rich fluids and their affinity to residual melts. Notably, the low permeability of sills limits fluid flow mostly to cooling joint fractures at roofs and base of the sills therefore sills acted as barriers rather than pathways for hydrocarbon fluid migration.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"468 - 485"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532416","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":"Solubility of Pt and Pd in Two-Phase Water-Poor Fluid of the NaCl–CO2–CO–(H2O) Composition at Low fO2 and High fCl2 (T = 950°C, P = 200 MPa)","authors":"A. G. Simakin,&nbsp;V. N. Devyatova,&nbsp;O. Yu. Shaposhnikova,&nbsp;O. A. Tyutyunnik","doi":"10.1134/S0869591126700402","DOIUrl":"10.1134/S0869591126700402","url":null,"abstract":"<p>The solubility of platinum and palladium in two phases of low-water fluid (NaCl melt and CO₂–CO–Cl₂(H₂O)) was experimentally studied at <i>P–T</i> parameters of the cumulus of ultramafic–mafic intrusions and low oxygen fugacity, <i>f</i>O₂ = CCO. The solubility of platinum as chloride in NaCl melt with several percent of dissolved carbon dioxide at <i>T</i> = 950°C and <i>P</i> = 200 MPa and increased chlorine fugacity maintained by the Ag–AgCl buffer is 23 ± 4 ppm, and that of palladium is 74 ± 26 ppm. At the same <i>P–T</i> parameters and chlorine fugacity at the FeCl₂–FeCl₃ buffer, the solubility of native platinum in CO₂–CO–Cl₂ fluid in the form of carbonyl and possibly mixed chloride–carbonyl complexes is 341 ± 110 ppm, and that of palladium was determined less accurately as 335 ppm. At high oxygen fugacity, the solubility of palladium in silicate melt, hydrothermal solution, and supercritical fluid is several orders of magnitude (2 to 4.5) higher than that of platinum. The solubility of native palladium in reduced fluid similar to or slightly lower than that of platinum may explain the elevated Pt/Pd ratios in some PGE ores, despite the similar mean contents of these elements in the primitive mantle and parent magmas of ultramafic–mafic intrusions. Estimates of the reduced fluid–sulfide melt partition coefficients based on the obtained solubility values give at the maximum CO content <span>({text{Kd}}_{{fl - slf}}^{{{text{Pt}}}})</span> = 0.47–6.5 and <span>({text{Kd}}_{{fl - slf}}^{{{text{Pd}}}})</span> = 0.02–0.13, which suggests a possible mechanism for the separation of platinum and palladium in the early postmagmatic process in sulfide-bearing cumulus with the participation of reduced carbon dioxide fluid at high chlorine fugacity.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"510 - 527"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532417","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":"Paleoproterozoic Andesite−Dacite−Rhyolite Volcanism in the Tim Backarc Basin of Sarmatia: Sources of the Melts, Crustal Evolution, and Geodynamic Scenarios","authors":"K. A. Savko,&nbsp;A. V. Samsonov,&nbsp;S. V. Tsybulyaev,&nbsp;E. Kh. Korish","doi":"10.1134/S0869591126700189","DOIUrl":"10.1134/S0869591126700189","url":null,"abstract":"<p>The study is focused on the petrogenesis of Paleoproterozoic volcanic rocks in the active continental margin of the Archean Kursk block. The largest Paleoproterozoic syncline of eastern Sarmatia is the Tim backarc basin (terrane), which hosts metamorphosed rocks of the calc-alkaline andesite−dacite−rhyolite (ADR) rock association, dated at 2.07–2.08 Ga. The ADR rocks formed via the differentiation of parental basaltic melt. The enriched mafic melts of the ADR association might have been derived from a mantle wedge metasomatized by fluids during the descent of the lower oceanic slab in the course of low-angle subduction. These enriched basaltic andesite melts entered the crust and continued differentiating in crustal intermediate chambers to give rise to the dacites and rhyolites.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"415 - 416"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532383","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":"Structure and Metamorphic History of the Lower and Middle Crust of the Anabar Province of the Siberian Craton Based on Data for Xenoliths from the Nurbinskaya Diatreme","authors":"M. Yu. Koreshkova,&nbsp;H. Downes,&nbsp;E. Yu. Akimova,&nbsp;M. V. Stifeeva,&nbsp;I. Peytcheva,&nbsp;D. Dimitrova,&nbsp;L. Macheva,&nbsp;A. N. Larionov,&nbsp;S. A. Sergeev,&nbsp;G. A. Lisovski,&nbsp;O. G. Safonov","doi":"10.1134/S0869591126700256","DOIUrl":"10.1134/S0869591126700256","url":null,"abstract":"<p>Felsic xenoliths from the Nyurbinskaya pipe in the Anabar province are represented by Grt-granulites and Grt-gneisses. A consideration of the metamorphic sequence and U–Pb zircon dating revealed that the crustal section contains rocks with different thermal histories. Lower crustal rocks were heated to 900°C 1.88–1.84 Byr ago. Upper-middle crustal rocks were not affected by post-collisional events. We believe this section is the juxtaposition of tectonic slices consisting of metamorphic complexes of different ages.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"403 - 405"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532403","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":"U–Pb Age of Zircons from Gneisses of the Mariinskaya Formation, Southern Urals, and Problems Related to the Precambrian in the Trans-Urals","authors":"T. A. Osipova,&nbsp;A. A. Krasnobaev,&nbsp;S. V. Busharina","doi":"10.1134/S0869591126700153","DOIUrl":"10.1134/S0869591126700153","url":null,"abstract":"<p>The paper presents results of U–Pb SHRIMP-II dating and describes some features of zircon grains from unmigmatized plagiogneisses of the Mariinsky Formation, Trans-Urals. It is shown that the zircon consists of rims, which grew as a result of granulite-facies metamorphism no older than the Late Riphean, and cores of detrital origin, dated within the range from the Archean–Proterozoic boundary to Late Riphean. The data suggest that before the onset of migmatization, the Mariinsky gneisses were formed independently of the Paleozoic Ural formations.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"408 - 409"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532405","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":"Crustal Ore-Bearing Carbonatites-Kuldimites of the Byrranga Mountains, Taimyr Peninsula: A Model for Mantle-Crust Interaction","authors":"V. F. Proskurnin,&nbsp;V. A. Saltanov","doi":"10.1134/S0869591126700268","DOIUrl":"10.1134/S0869591126700268","url":null,"abstract":"<p>During small-scale geological survey (2004–2017) and the preparation of the State Geological Maps at a scale of 1 : 1 000 000 (third generation) in the Byrranga Mountains of the Taimyr fold system, areas of the distribution of Middle–Late Triassic crustal carbonatites-kuldimites were identified. Patterns of their distribution, petrographic, mineralogical, isotope-geochronological, and isotope-geochemical features allow us to outline a model for the origin of ore-bearing carbonatites and fluidolites during the interaction of plumogenic mantle magmas and salt- and water-saturated upper crustal carbonate rocks in intermediate chambers.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"422 - 425"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532386","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":"Geodynamic Evolution of the Sarma Segment (Akitkan Orogenic Belt, Siberian Craton) in the Archean–Proterozoic","authors":"U. S. Efremova,&nbsp;T. V. Donskaya,&nbsp;D. P. Gladkochub,&nbsp;A. M. Mazukabzov,&nbsp;A. V. Ivanov,&nbsp;N. V. Bryansky","doi":"10.1134/S0869591126700128","DOIUrl":"10.1134/S0869591126700128","url":null,"abstract":"<p>Based on the study of metaterrigenous rocks of the Sarma segment of the Akitkan orogenic belt, it has been established that the Khargitui Formation combines three units of different age (2.7–2.5, 2.15–1.95, and 1.00–0.72 Ga). The rocks of the Ilikta Formation represent molasse deposited during the orogenic collapse stage (1.95–1.91 Ga). The Anai Formation was accumulated in the Tonian within intracontinental basins. The obtained data supplement the geodynamic model of the Sarma segment in the Archean–Proterozoic.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"34 4","pages":"397 - 399"},"PeriodicalIF":1.0,"publicationDate":"2026-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148532387","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}