Petrology最新文献

{"title":"Geodynamics of a Breakup of Western Part of the Karelian Craton: Data on 2.1 Ga Mafic Magmatism","authors":"A. V. Samsonov,&nbsp;A. V. Stepanova,&nbsp;E. B. Salnikova,&nbsp;Yu. O. Larionova,&nbsp;A. N. Larionov","doi":"10.1134/S0869591123060085","DOIUrl":"10.1134/S0869591123060085","url":null,"abstract":"<p>Mafic intraplate magmatism is the main source of information about the geodynamics of processes that lead to the breakup of continental blocks. The article discusses geodynamics of the breakup of the Archean supercraton Superia in the Middle Paleoproterozoic. The discussion is based on data on 2.1 Ga magmatism in the Karelian Craton, where mafic igneous rocks of this age are represented by tholeiites of two geochemical types: depleted and enriched. Geochemically close to N-MORB, depleted tholeiites were studied in the Northern Ladoga Region where they form dike swarms at ca. 2111 ± 6 Ma (U-Pb, SIMS, zircon) in the Hatunoiya locality, and pillow lavas and sills in the Lake Maloe Jänisjärvi locality. Enriched tholeiites were studied in the Lake Tulos locality where they form a large swarm of doleritic dikes of age 2118 ± 5 Ma (U-Pb, ID-TIMS, baddeleyite). The results of these studies provide deeper insight into 2.1 Ga mafic magmatism. Depleted tholeiites with N-MORB geochemistry have a wide spatial distribution in the Karelian Craton and could be formed via decompression melting of a depleted asthenospheric mantle, raising melts along the extension zones, and minimal contamination by the Archean crust. According to modelling results, enriched tholeiitic melts probably occurred due to differentiation and crustal contamination of rising depleted tholeiitic melts through more rigid Archean crustal blocks. Data on ca. 2.1 Ga mafic magmatism in the Karelian craton are difficult to explain within the mantle plume rise model, but are consistent with the model of lithosphere extension due to a retreat of a subduction zone in the northeastern margin of the craton, in the Lapland-Kola Ocean at 2.0–2.2 Ga. The intensive thinning and rupture of the Archean continental lithosphere and opening of an oceanic basin at the western margin of the Karelian craton were probably controlled by the suture zone of the junction of Neoarchean and Paleoarchean crustal blocks, traced in the western part of the Karelian craton. An additional factor that led to the ca. 2.1 Ga lithospheric breakup could be a rise of a deep-seated mantle plume in the Hearne craton, neighboring to the Karelian craton in the Archean Superia supercraton.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"581 - 603"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473292","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":"Application of Proxy Minerals for Evaluation of the Oxygen Isotope Composition of Felsic Melts","authors":"E. O. Dubinina,&nbsp;L. Ya. Aranovich","doi":"10.1134/S0869591123060073","DOIUrl":"10.1134/S0869591123060073","url":null,"abstract":"<div><p>The problems associated with the use of quartz and zircon as proxy minerals for the reconstruction of δ¹⁸O values in acidic melts are considered. It is shown that the correction values Δ(<i>Qz</i>–R) and Δ(R–<i>Zrn</i>) used for the reconstructions are not strictly constant and depend on the mineral composition of the rock and the closure temperature of the oxygen isotopic system of the proxy mineral (<i>T</i>_q, <i>T</i>_z–closure temperature of quartz and zircon, respectively). The applicability of quartz was estimated using an equation for Δ(<i>Qz</i>–R) calculation, which takes into account <i>T</i>_q and the mineral composition of rocks. Using the leucogranites of the Raumid massif (South Pamirs) as an example, it was shown that this correction can be approximated by constant value only under definite conditions. The value of Δ(R–<i>Zrn</i>) was estimated using approach based on calculating the weighted average fractionation coefficient and independent estimates Tz using a zirconium thermometer. It was shown for leucogranite porphyries of the Omsukchan trough that this correction for identical rocks varies from 1.3 to 1.9 ‰, unlike Δ(R–<i>Zrn</i>) = 2.1 determined by the dependence on the SiO₂ content (Lackey et al., 2008). The advantages and limitations on the application of quartz and zircon as proxy minerals have been analyzed.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"664 - 673"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1134/S0869591123060073.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Crystal Size Distribution as a Key to Understanding Protocumulus Evolution in Layered Intrusions: Experiments, Calculations, and Practice of CSD Extraction","authors":"S. N. Sobolev,&nbsp;A. A. Ariskin,&nbsp;G. S. Nikolaev,&nbsp;I. V. Pshenitsyn","doi":"10.1134/S0869591123060097","DOIUrl":"10.1134/S0869591123060097","url":null,"abstract":"<p>The paper provides a review of calculations and experimental approaches to reproducing three types of crystal size distributions (log-linear, bimodal, lognormal CSD) and systematizes publications on CSD data in rocks of ten known layered massifs. For a more detailed discussion, the results for plagiodunite samples from the Yoko-Dovyren massif, northern Baikal region, Russia, harzburgite from the marginal zone of the Monchegorsk pluton, and urtites from the Lovozero intrusion, Murmansk region, Russia, were selected. Possible causes and scenarios for the formation of three types of CSD established for these intrusive objects are presented.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"648 - 663"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473057","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":"Low Crustal Fluid Reservoirs in Ultramafic Cumulates of Kamchatka","authors":"A. G. Simakin,&nbsp;O. Yu. Shaposhikova","doi":"10.1134/S0869591123060036","DOIUrl":"10.1134/S0869591123060036","url":null,"abstract":"<p>Based on published geophysical and petrological data, lower crustal fluid reservoirs have been proposed below the Klyuchevskoy Volcano, expressed as a low <i>V</i>_<i>p</i>/<i>V</i>_<i>s</i> anomaly. A high <i>V</i>_<i>p</i>/<i>V</i>_<i>s</i> anomaly under the proposed fluid reservoir is interpreted as a zone of magma accumulation. The localization of fluids in these reservoirs in the ductile lower crust can vary from isolated inclusions to filling of microfractures over a time scale of several months. Using a simplified poroelastic model, it is shown that the transition in the topology of pore space filled with fluid or melt can provide the observed changes in <i>V</i>_<i>p</i>/<i>V</i>_<i>s</i> in the anomalies of high and low values at a melt content of several vol % and fluid content less than 1 vol %, respectively. In zones of active volcanism, such as the Klyuchevskaya group of volcanoes (KGV), fluid reservoirs are localized in ultramafic cumulates formed during the early high-temperature stage of magma fractionation. Ultramafic xenoliths in the products of eruptions of the KGV and Avachinsky volcanoes, often interpreted as mantle rocks, formed at pressures of about 5 kbar or depths of about 18–20 km in accordance with two-pyroxene geo-thermobarometry and the content of volatiles in melt inclusions in olivine and spinel. When crossing by ascending magmas, the fluid-containing reservoir experiences mechanical failure and injects a certain amount of fluid into the magma, which then captures pieces of crushed magmatic cumulates. The composition of melt inclusions in olivine can reveal records of the magma-fluid interaction.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"705 - 717"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473052","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":"Effects of the Content of Alkalis on Zircon Solubility in Silicate Melts","authors":"A. A. Borisov,&nbsp;A. N. Koshlyakova","doi":"10.1134/S0869591123060048","DOIUrl":"10.1134/S0869591123060048","url":null,"abstract":"<p>The effects of the content of alkalis on zircon solubility in multicomponent model silicate melts was experimentally studied within the temperature range of 1300–1400°C and 1 atm total pressure. It was demonstrated that the addition of Na₂O and K₂O to the melt results in a comparable increase in zircon solubility. The advantages and disadvantages of the parameters describing the effects of the melt composition on zircon solubility are briefly discussed.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"674 - 680"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473282","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":"Newly Identified A-type Granite in Western Yangtze Block and Its Geochemistry Characteristics: Evidence for Ridge Subduction beneath the South China Craton","authors":"Awei Mabi,&nbsp;Yanlong Li,&nbsp;Mingchun Zhang,&nbsp;Zhengxi Yang,&nbsp;Niuben Yu","doi":"10.1134/S0869591123060024","DOIUrl":"10.1134/S0869591123060024","url":null,"abstract":"<p>Numerous Neoproterozoic granitic intrusions occur over a north-south distance of more than 700 km in the western Yangtze Block. In this paper, we use zircon U-Pb age, Lu-Hf isotopic, and whole-rock geochemical data to show that the Shimian granitic pluton, which was previously thought to be S-type granite in the area, is actually A-type granite. The selected fresh samples for this study are mainly porphyritic biotite monzogranites. They are weak peraluminous, A₂-subtype granites, displaying high contents of SiO₂ and K₂O, low CaO, and Na₂O, with the characteristics of high silica, rich potassium, and low sodium. They are enriched in incompatible trace elements, but low in trace elements compatible in mafic silicates and feldspars, and they are chemically characterized by having high REE and Ga abundances and low Al, Ni, Ba, Sr, and Eu abundances. The major and trace element behavior suggests that the granites underwent the process of advanced fractional crystallization and were likely generated by crustal partial melting. Zircon U-Pb age shows the Shimian granitic pluton was emplaced at 728 ± 20 Ma. The studied granites yield an average ¹⁷⁶Hf/¹⁷⁷Hf value of 0.282363 (ε_Hf = 0.8) with a 94% confidence interval of 0.282334 to 0.282384 (ε_Hf = −0.1 to 1.7), indicating that they are derived from the remelting of juvenile continental crust. We suggest that this newly identified A-type granite at Shimian, southwestern China, was more plausibly generated in an extensional setting as a result of slab window caused by ridge subduction, which can account not only for the formation of voluminous granitoids, but also for the basalts, boninitic pillow lavas, and SSZ-type ophiolites in western Yangtze Block.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"681 - 704"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473055","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":"Sources of Cuprous Sulfide Mineralization and High-Ni Olivine of the Rudnaya Dyke (Imangda Cluster, Norilsk region): Based on Compositional, Isotope and Model Data","authors":"V. D. Brovchenko,&nbsp;I. A. Kirillina,&nbsp;M. A. Yudovskaya,&nbsp;G. Costin,&nbsp;I. V. Pshenitsyn,&nbsp;E. V. Kovalchuk,&nbsp;Yu. O. Larionova,&nbsp;Yu. D. Gritsenko,&nbsp;A. A. Ketrov,&nbsp;S. F. Sluzhenikin","doi":"10.1134/S086959112306005X","DOIUrl":"10.1134/S086959112306005X","url":null,"abstract":"<div><p>The Rudnaya dyke of the Imangda ore cluster is composed of weakly differentiated olivine-bearing to olivine gabbrodolerites with globular and interstitial sulfides of a chalcopyrite–cubanite- (pentlandite-pyrrhotite) composition. Along with sulfide mineralization, gabbrodolerites of the dyke contain xenoliths of hornfelsed basalts, abundant amygdales and rare grains of zoned olivine-1 <i>Fo</i>_90–47 that coexists with subhedral olivine <i>Fo</i>_74–36 of the second generation. Modeling with the COMAGMAT and alphaMELTS programs showed that high-Mg <i>Ol</i>-1 with Cr-spinel inclusions cannot be crystallized from a Fe-enriched tholeiitic melt with 4.8–7.3 wt % MgO and 11.6–16.7 wt % total Fe₂O₃ that is parental for the dyke. The variation trend and high Ni up to 0.5 wt % NiO in the cores of xenocrystic olivine <i>Fo</i>_90–76 in contrast to maximum <i>Fo</i>₈₃ and 0.4 wt % NiO in olivine from the ore-bearing intrusions and picritic basalts of the Norilsk region point toward the presence of deep-seated cumulates of picritic magmas, which had not exchanged with sulfide liquid. Platinum group element (PGE) abundances increase (up to 2.2 ppm) with increasing Cu/Ni in the whole rocks and proportions of pentlandite in a sulfide association. A specific pattern of chalcophile metal distribution with Ni, Os and Ir minima, elevated Cu/Ni (5–15) and Cu/Pd (3200–10 900) along with lower PGE tenor (PGE content in 100% sulfide) of sulfides (2–65 ppm) and Pd content in pentlandite (&lt;175 ppm) compared to those of the ore-bearing intrusions suggest that cuprous sulfide mineralization was not physically captured from highly fractionated sulfide fractions of ore-bearing magmas but is cogenetic with a magma of the dyke. Sulfide saturation, near-simultaneous with fluid saturation and degassing, was achieved in the dyke conduit due to assimilation of sedimentary sulfur and volatiles from Devonian evaporites that is supported by the heavy S isotope composition of dyke’s sulfides with the average δ³⁴S = 14.7 ±1.1‰ (<i>n</i> = 31) close to the values for sulfides from the endocontact zones of the Imangda ore-bearing intrusions hosted by the Devonian sequences. The initial isotopic characteristics of dyke rocks (Sr_i 0.70517–0.70532, ɛNd from –0.4 to 0.8) imply its comagmatic origin with the Norilsk-type intrusions whereas the overall data do not exclude its spatial connection with an upper crustal conduit network of the ore-bearing magmas.</p></div>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"624 - 647"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473284","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":"Metasomatic Transformation of Amphibolites into Corundum-Bearing Plagioclasites: Zoning and Numerical Model of the Process with Reference to the Unique Khitostrov Corundum Deposit, Fennoscandian Shield","authors":"S. A. Bushmin,&nbsp;A. B. Kol’tsov,&nbsp;Yu. M. Lebedeva,&nbsp;E. V. Savva","doi":"10.1134/S0869591123060061","DOIUrl":"10.1134/S0869591123060061","url":null,"abstract":"<p>The paper presents results of a study of middle crustal (amphibolite-facies level) desilicated rocks exemplified by corundum-bearing plagioclasites developing after metabasites at the unique Khitostrov corundum deposit in the Belomorian–Lapland orogen of the Fennoscandian shield, with emphasis placed onto newly acquired geological data, documentation and analysis of the metasomatic zoning, determination of the <i>P–T</i> conditions of its formation, and a model of the metasomatic process.</p>","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"31 6","pages":"604 - 623"},"PeriodicalIF":1.5,"publicationDate":"2023-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138473291","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":"Early Paleozoic Tectonothermal Evolution of the Khan-Khukhay Metamorphic Complex, Northern Mongolia","authors":"O. P. Polyansky, A. Yu. Selyatitskii, S. V. Zinoviev, A. V. Babichev","doi":"10.1134/s0869591123050041","DOIUrl":"https://doi.org/10.1134/s0869591123050041","url":null,"abstract":"","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"59 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135509130","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":"Formation Stages and Conditions of Carbonate–Silicate Veins and Their Wall-Rock Aureoles in the Early Proterozoic Complexes of the Belomorian Mobile Belt, Northern Karelia","authors":"I. S. Volkov, V. M. Kozlovskii","doi":"10.1134/s0869591123050077","DOIUrl":"https://doi.org/10.1134/s0869591123050077","url":null,"abstract":"","PeriodicalId":20026,"journal":{"name":"Petrology","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134934825","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}