Comprehensive petrological and isotope-geochemical study of marble was carried out in the upper part of the Sortavala Group of the northeastern lense at the Ruskeala deposit in the Northern Ladoga area. The petrological study showed that the carbonate rocks of the Sortavala Group underwent medium-temperature low-pressure amphibolite-facies metamorphism. The mineral assemblages of Ruskeala marbles were

Granulite complex on the left side of the Bol. Kuonamka River, below the mouth of the Khapchan River, is composed of melanocratic and mesocratic orthopyroxene–clinopyroxene crystalline schists and leucocratic orthopyroxene and orthopyroxene–clinopyroxene plagiogneisses. The granulites formed after mafic to felsic volcanoplutonic rocks with rare sedimentary interlayers. In terms of chemical composition

The paper considers the results of geochronological (U-Pb method, ID-TIMS), geochemical, and Sm-Nd isotopic studies of granitoids, volcanics, and terrigenous rocks of the eastern Dzabkhan terrane, as well as felsic volcanics of the Dzabkhan Formation in its southern part. It is established that the post-kinematic granitoids of the Dzabhan–Mandal Zone, Erdenekhairkhan, and Bogdoingol blocks were formed

Abstract— The paper presents newly acquired isotope-geochemical and U–Pb isotope zircon dating (SHRIMP) results on four posttectonic granitoid massifs in the southeastern part of the Karelian Granite–Greenstone Province (GGP) in the Fennoscandian Shield. The massifs are located near the Hautavaara Structure, in the southeastern part of the Mesoarchean (3.05–2.85 Ga) Vedlozero–Segozero Greenstone Belt

Abstract The metabasites of the Tim Formation occur in the Paleoproterozoic Orel, Tim–Yastrebovka, and Avilsky synforms in the Archean Kursk block of Eastern Sarmatia. The volcanics are picrites, picrobasalts, basalts, and basaltic andesites metamorphosed to the greenschist and epidote-amphibolite facies. Their zircon (SIMS) age is 2099 ± 8 Ma. Based on their (Gd/Yb)n and Ti/Y ratios, the volcanics

Abstract The paper reports major relations and trends determined in the distributions of trace elements and the Sr and Nd isotope composition of leucogranites of the Turga massif in Eastern Transbaikalia. Three varieties of the leucogranites are distinguished: porphyritic biotite granites, equigranular granites with Li-siderophyllite, and amazonite granites that make up small stocks and dikes. All

Abstract An experimental study of the form of metallic iron deposited from silicate melt at a drastic fO2 decrease was conducted at 1400°C and 1 atm total pressure. The oxygen fugacity was controlled by CO/CO2 gas mixture. It was demonstrated that the metallic iron initially forms a network of euhedral crystals near the melt surface. With an increase in experimental duration, the iron loses its crystalline

Cambrian, Devonian and Permian differentiated intrusions made up of subalkaline and alkaline gabbro, foidolite, nepheline and alkaline syenites, and rare carbonatites compose an area in the northern part of the Kuznetsk Alatau alkaline igneous province. Primary melts of the intrusions were moderately fractionated ((La/Yb)N up to 7–12) and could be derived by 1–10% partial melting of mantle spinel lherzolite

Abstract A numerical thermodynamic model is proposed for one of the most important geological fluid systems, the ternary H2O–CO2–NaCl system, at P-T conditions of the middle and lower crust and crust-mantle boundary (up to P = 20 kbar and up to T = 1400°C). The form of the model is analoguous to the model developed earlier for the system H2O–CO2–CaCl2. The model is based on an equation for the Gibbs

Abstract We conducted the geochemical modeling of trace element contents for primary melts of olivine-phyric rocks from Kamchatsky Mys. This modeling reveals substantial chemical heterogeneity of their source while the average source composition is close to the enriched DMM (E-DMM). The average estimation of the melting degree is in the range from 9.1 ± 3.8% for the model of modal batch melting to

Abstract This study was focused on the estimation and geodynamic interpretation of the contents and character of distribution of highly siderophile and chalcophile elements in rock samples from mafic–ultramafic assemblage sampled at the Stalemate Ridge in the NW Pacific and the Shirshov Rise in the Bering Sea. All of the samples were collected during Cruise 249 of German R/V Sonne. These mafic–ultramafic

Abstract The paper presents the first detailed mineralogical and petrographic information on the clastic components of three suevite varieties from the Kara astrobleme in the Pay-Khoy Ridge, Russian Arctic, including features of their morphology, inner structure, chemical and mineral phase composition of the suevite impact glasses. Data on the suevites are consistent with the earlier classification

Abstract The Al2SiO5 polymorphs (andalusite, kyanite, and sillimanite), which are widespread in aluminous metamorphic rocks, gain increasing importance as industrial sources for producing aluminum oxide, silumin, and aluminum. The polymetamorphic history of a series of metamorphic complexes of Al-rich metapelites in the Yenisei Range, with rocks containing the Al silicate triple-point assemblage (all

The Eastern Mongolia Volcanic Area (EMVA) is the largest Late Mesozoic intracontinental volcanic area of East Asia. Its magmatic activity lasted from ~ 170 Ma to the beginning of Cenozoic, but the peak of activity occurred between 135 and 105 Ma. It was accompanied by rifting and formation of NE-trending grabens and troughs filled with thick volcanic sequence. The largest volcanic eruptions occurred

Abstract Eclogite-like rocks of the Olkhon terrane correspond to two types according to the mode of occurrence and mineral compositions, although both types developed after the same type of gabbro of a single complex. The rocks of the first type are composed of garnet, clinopyroxene, pargasite (± scapolite, ± anorthite, ± spinel) and occur as thin veins or patches in the marginal parts of several small

Abstract This paper reports new mineral and whole-rock geochemical data on the acid volcano-plutonic rocks of the Tusham Ring Complex (TRC) from the Neoproterozoic Malani Igneous Suite (MIS), northwestern Peninsular India and discusses their magmatic evolution, tectonic implication, and geodynamic history. Geochemically, the investigated rocks have the characteristics of hypersolvus, high-K calc-alkaline

Abstract Data on xenoliths carried by lavas of Avacha volcano and ejected during eruptions are used in discussing the partial melting of metasomatized rocks of the lithospheric mantle (which were tectonically reformed by seismic events beneath the frontal zone of Avacha volcano) and the associated growth of minerals from a gas phase in open fractures above the magma chamber feeding the volcano. Based

A model of the geological evolution of the Japan and Okhotsk seas was developed based on radioisotope age, mineralogical, and isotope-geochemical study of the Late Mesozoic–Cenozoic volcanic rocks. The geodynamic settings of volcanic stages were determined as follows: (1) the Late Cretaceous continental-margin (calc-alkaline), (2) the Eocene transform-margin (adakite) in the Sea of Okhotsk, (3) the

AbstractIntrusions of the Zubovsky type (1) are commonly dominated by troctolite in their ultramafic parts and have an insignificant number (if any) of ultramafic units; (2) occur among olivine and olivine-bearing gabbro-dolerites and often show evidence of a number of accumulation of cumulus olivine, (3) have weakly pronounced (if any) taxitic gabbrodolerite units; (4) include widespread leucocratic

Pb and Nd isotopic composition of granitoids from the Lake Zone, Mongolian and Gobi Altai was analyzed to decipher the continental crustal growth of heterogeneous terranes of the Central Asian orogenic belt. The granitoids were generated in the Late Neoproterozoic–Early Paleozoic juvenile crust of the Lake Zone during island-arc, accretion, and post-accretionary stages at 535–440 Ma. Their Pb and Nd

The mineralogical and geochemical features of melted rocks of the Khamaryn–Khural–Khiid combustion metamorphic complex in Eastern Mongolia have been characterized for the first time and conditions of their formation have been estimated. Clinkers and paralavas were formed through partial melting of Early Cretaceous sedimentary sequence under the effect of wild coal fires, which have happened since at

AbstractTo provide new insights into the origin and evolution of kimberlitic magmas with different diamond concentrations from the Arkhangelsk diamond province in north-western Russia, we examined the major- and trace-element compositions of ilmenite from diamondiferous kimberlite of the Grib pipe and diamond-barren kimberlites from the Kepino cluster (Stepnaya and TsNIGRI–Arkhangelskaya pipes). Ilmenite

Serpentinized peridotites (lherzolite to harzburgite) with relict coarse-grained protogranular and porphyroclastic matrix and locally developed fine-grained spinel–pyroxene microstructures were sampled from a previously unknown tectonic exposure of the Mid-Atlantic Ridge (17°04′–17°10′ N). The mineral composition of the coarse-grained relics is typical of abyssal residual peridotites and corresponds

AbstractThe results of a study of mineral-hosted melt inclusions were used to reconstruct the evolution of tholeiitic melts that produced the rocks of the shield edifice of Wangtian’e volcano, Northeast China, including the P–T parameters of their crystallization. Primary melt inclusions were studied in plagioclase of tholeiitic basalts. They contain “dry” Fe-rich silicate glass or a crystallized fine-grained

The behavior of four isotope systems (δ18О, δ13С, δ88Sr and 87Sr/86Sr) during submarine precipitation of inorganic carbonates is considered using the Lost City hydrothermal field as an example of “natural laboratory”. During the carbonate precipitation, the isotope composition, T, and pH of hydrothermal solution change due to mixing of the “end member” Lost City fluid with ocean water. The composition

New petrographic, geochemical, and isotopic (Sr, Nd, and δ18О) data on olivine and pyroxene phenocrysts provide constraints on the composition and crustal evolution of primary melts of Paleoproterozoic (2.40 Ga) picrodoleritic sills in the northwest Kola province, Fennoscandian Shield. The picrodolerites form differentiated sills with S-shaped compositional profiles. Their chilled margins comprise

AbstractDeep seismic studies of the upper mantle conducted in Russia with the use of nuclear explosions and laboratory studies of mantle materials at high pressure and temperature have revealed new structural and petrophysical features of the upper mantle beneath Northern Eurasia. These features are hard to explain within the framework of current understanding of the structure of the continental lithosphere

The paper reports the results of melting experiments on the fluorite-enriched rhyolites of the Nyalga Basin (Central Mongolia). The fluoride–calcium (F–Ca) melt was obtained in a wide range of P-T parameters (1250–750°С, 5.5–1 kbar). Fluoride–silicate liquid immiscibility was observed at F > 2.5 wt % and CaO > 5.3 wt % in the initial system. An increase of temperature and pressure was accompanied by

AbstractThe paper presents data on sulfide globules in picrodolerites from a bottom apophysis of the Yoko-Dovyren massif, northern Transbaikalia. Textural features of the rocks indicate that they crystallized at rapid magma cooling. Their composition is similar to that of chilled olivine gabbronorites from the lower contact of the massif. Many droplet-shaped sulfides, which range from 2 to 15 mm, were

AbstractMineral zoning in fenites around miaskite intrusions of the Vishnevye Mountains complex can be interpreted as a magmatic-replacement zonal metasomatic aureole (in D.S. Korzhinskii’s understanding): the metasomatic transformations of the fenitized gneisses under the effect of deep alkaline fluid eventually resulted in the derivation of nepheline syenite eutectic melt. Based on the P–T–fO2 parameters

The mechanisms of the occurrence of nonequilibrium oxygen isotope fractionation between olivine and plagioclase phenocrysts and the groundmass of rocks (from alkaline basalts to alkaline rhyolites) of Changbaishan volcano are considered. The basaltic trachyandesite–trachyte–comendite–pantellerite rock series shows a systematic increase of the δ18O values of feldspar (from 5.4 to 7.8‰) and the rock

AbstractIn the northern part of the Anabar Shield, orthopyroxene plagiogneisses of the granulite Daldyn Group host lenses of mafic rocks surrounded by melanocratic rims. According to their chemical composition, the mafic rocks correspond to subalkaline gabbro, the plagiogneisses correspond to granodiorites contaminated with mafic material, and the rims are diorites. The orthopyroxene plagiogneisses

AbstractGeological-structural and petrological data acquired by the authors on the most widely spread metamorphic associations of the Belomorian Mobile Belt in northern Karelia, Russia, indicate that the rocks belong to five age groups (0–IV), which were produced by metamorphism of protoliths of different composition and genesis. The Paleoproterozoic metamorphic associations were formed by three successive

Abstract–Anorthosites of the Olonkhuduk pluton of the Central Asian Orogenic Belt are dated at 1772 ± 1 Ma (ID TIMS U-Pb zircon method). Similar age estimate (1784 ± 10 Ma) was previously obtained for anorthosite of the Khungilingol pluton from the Ider block of the Tarbagatai terrane. These data indicate a significant time gap (70–60 Ma) between the collision that formed the Early Precambrian blocks

1860-Ma within-plate mafic rocks of the Eastern Murman Sill Province were studied in the northern part of the Murmansk Craton, where they compose sheet bodies (sills) up to 100 m thick in Archean granitoids and gneisses. The sills have a simple inner structure, show no macroscopic signs of in situ differentiation even in large bodies, and consist of homogenous medium-grained poikilophitic dolerites

Mantle xenoliths were found in alkaline basalts of Tokinsky Stanovik (TSt) in the Dzhugdzhur-Stanovoy superterrane (DS) and Vitim plateau (VP) in the Barguzin–Vitim superterrane (BV) (Stanovoy suture area) at junction of the Central Asian Orogenic Belt (CAOB) and the Siberian craton (SC). Xenoliths from TSt basalts are represented by spinel lherzolites, harzburgites, wehrlites; while VP basalts frequently

AbstractThe paper presents results of comprehensive studies of the rock association composing the lower zone of the northeastern part of the Monchetundra mafic massif in the Monchegorsk ore district. The zone consists of orthopyroxenite, plagioorthopyroxenite, and norite, which are variably amphibolized and host numerous gabbroid injections from the upper zone of the massif. The chemical composition

AbstractThe paper presents data of U–Pb (ID-TIMS) geochronologic studies of schorlomite–morimotoite–andradite garnet from the Vuoriyarvi, Sallanlatva, and Salmagorsky massifs in the Kola alkaline province. The garnet is relatively rich in U (5–9 ppm) and poor in common Pb (Pbc/Pbt = 0.2–0.7), contains U as an isomorphous component, and does not host inclusions of any U-bearing minerals. The U–Pb ages

AbstractProperties of fluids in high-pressure granulites were studied in HP granulites (~8.7–11 kbar, ~800–900°С) and syngranulite fluid infiltration-driven HP metasomatites (~11–9 kbar, ~920–850°С) from the Lapland granulite belt of the Fennoscandian Shield. The study involved large-scale mapping of the rocks, microthermometry of mineral-hosted fluid inclusions, multiequilibrium mineral thermobarometry

An effective method for identifying the tectonic-magmatic causes of metamorphism is the reconstruction and analysis of P–T–t paths, which can be used to develop a model of rock evolution with time in the “pressure–temperature–time” coordinates. This approach is most widely used in interpreting the development of orogens with a polycyclic history, where different types of metamorphism are combined in

The rocks of the Olkhon terrane experienced high-grade regional metamorphism reaching granulite facies. In addition to regional metamorphism, they were subjected to contact metamorphism and autometamorphism (mafic dikes). Three types of regional metamorphism have been distinguished. A terrane collage north of the Orso Zone revealed two stages of regional metamorphism: early-stage granulite metamorphism

The detailed mineralogical-geochemical study of eclogites and their retrograde products (amphibolites in a rim of eclogite boudin) from Vichennaya Luda Island (Keret Archipelago, White Sea) revealed systematic variations in major-, trace and rare-earth element composition of rock-forming minerals, which should be taken into account in geochronological and thermobarometric studies. Garnets from garnet–amphibole

AbstractThe origin of rare-metal deposits in granites is considered with regard for experimental data, which place constraints onto interpretations of geological materials and the genetic models. The role of both magmatic and hydrothermal–metasomatic factors in the formation of various types of rare-metal deposits is discussed. The saturation concentrations of Ta and Nb in granite melt significantly

AbstractThe paper presents the first data on the Sr and Nd isotope composition of rocks from a unique collection of magmatic rocks of all petrographic types (basalts, gabbro, and peridotites) belonging to the lithosphere at the convergent plate boundary in the Aleutian Arc area. The rock samples were collected over large areas in the Northwest Pacific and Bering Sea. The results of this study provide

The paper reports experimental data on the partial melting of hydrous peridotite and basalt at pressures up to 4 GPa and temperatures up to 1400°С, as well as peridotite–basalt association in the presence of alkaline water–carbonate fluid as an experimental model of mantle reservoir with subducted oceanic protoliths. At partial melting of the hydrous peridotite at 3.7–4.0 GPa and 1000–1300°С, critical

The results of petrological-geochemical and isotope-geochemical studies of the Late Pleistocene-Holocene lavas of the Kazbek neovolcanic center, one of the largest centers of youngest magmatism in the Greater Caucasus, are presented. It has been established that the volcanic rocks of the Kazbek center form a continuous compositional series basaltic (trachy-)andesites–(trachy-)andesites–dacites with

AbstractThe paper presents results of experimental studies of the behavior of volatile components (Cl, F, CO2, and H2O) in fluid–magmatic systems. The maximum Cl content in magmatic melts depends mainly on the composition of the melt and less on pressure (10–300 MPa) and temperature (800–1000°C). The Cl content in the melt increases from 0.2–0.3 to 3–5 wt % with increasing Ca content during the transition

The paper is dedicated to the study of the Devonian magmatic association of the Eastern Azov region, which is a part of the Pripyat-Dnieper-Donets rift zone. The association includes gabbros, peridotites, pyroxenites, and lamprophyre dikes of the Pokrovo-Kireevsky massif (PKM) and picrites, picrobasalts, and basalts of the Anton-Taram Formation (ATF). Analysis of clinopyroxenes of different generations

AbstractThe paper presents newly obtained geochemical data on outer-contact rocks and carbonate-replacement skarns of the Yoko-Dovyren layered ultramafic–mafic intrusion in the northern Baikal area. The rocks initially contained CO2-rich fluid with a high oxygen fugacity (up to NNO + 3–4), which was generated by the partial decomposition of dolomite and by reactions between SiO2 and carbonates. The

New petrographic, geochemical, and Sm-Nd isotopic data provide constraints on the petrogenesis of ca. 2400 Ma gabbronorite, picrodolerite and dolerite mafic sills and dikes in the Liinakhamari and Sorvaranger areas, Kola–Norwegian terrane, Northern Fennoscandia. The sills are differentiated. Their chilled margins are composed of porphyritic picrodolerite with olivine (Fo92-81) and clinopyroxene (Mg#

AbstractThe migration of helium from the crystal lattices of sulfides (pyrite, pyrrhotite, chalcopyrite, bornite, and sphalerite) and sulfosalts (tennantite and tetrahedrite) was studied. It was shown that helium occurs in submicrometer inclusions of uranium- and thorium-bearing minerals. The curves of helium thermal desorption from the sulfide and sulfosalts were obtained by the step-heating method

The Tuva–Mongolian terrane (TMT) of the Central Asian Orogenic Belt is a composite structure with a Vendian–Cambrian terrigenous–carbonate cover. The formation of the northern part of TMT is marked by the granitoids of the Sumsunur Complex with an age of 785 ± 11 Ma. The Sangilen and Khan-Khukhay blocks of its southern part also form a composite structure, which originated during Early Paleozoic (500–490

AbstractThe paper presents pioneering data on the comparative study of impact glasses from the Zhamanshin crater and lunar regolith (delivered by the Luna 16, 20, and 24 probes). The data were acquired using analytical techniques of ultrahigh spatial resolution. Many of the melt and condensate impact glasses, both terrestrial and lunar, are similar in inner structure and composition, which were controlled

Geological and mineralogical data are reported on the manganese occurrences of the Olkhon terrane (Western Baikal region), which are localized in metadolerites of the Ustkrestovsky Complex, high-temperature mafic hornfels, granites, calcitic marbles and calciphyres, and occasionally are developed as separate veins in gneiss granites or small lenses in quartzites. Most of them are made up of high-temperature

The paper reports the results of an experimental study of phase relations and distribution of elements in silicate melt–salt melt systems (carbonate, phosphate, fluoride, chloride), silicate melt I – silicate melt II, and fluid–magmatic systems in the presence of alkali metal fluorides. Extraction of a number of ore elements (Y, REE, Sr, Ba, Ti, Nb, Zr, Ta, W, Mo, Pb) by salt components was studied

AbstractThe salt components of aqueous and aqueous-carbonic fluids are very important agents of metasomatism and partial melting of crustal and mantle rocks. The paper presents examples and synthesized data on mineral associations in granulite- and amphibolite-facies rocks of various composition in the middle and lower crust and in upper-mantle eclogites and peridotites that provide evidence of reactions

AbstractThe paper reports newly obtained data that append older results of experimental modeling of granitization processes. The experiments were aimed at modeling high-temperature metasomatism of mafic rocks, a process that involves the transfer of major components at 750°C and 500 MPa at a pressure gradient. The source of the transported Si, Ca, and Mg in the experiments was garnet. The solution

AbstractThe paper reports results of an experimental study of amphibole crystallization from the highly magnesian andesite melt of Shiveluch volcano, Kamchatka. The experiments were carried out in IHPV at 300 MPa and 940–980°С in iron-saturated platinum capsules, using rapid quenching and temperature oscillations (in some experiments). The redox state of iron in the system was measured before and after

AbstractMany years ago, V. S. Sobolev suggested that the reason for the relative prevalence of intrusive and effusive rock masses in the earth’s crust lies in the patterns of viscosity of water-bearing magmas in a variable field of temperatures and pressures. Alas, in those years it was not possible to solve this problem on a quantitative physical-chemical basis, since experimental and theoretical

AbstractWe present the results of analogue experiments carried out in a piston–cylinder apparatus at 750–900°C and 2.9 GPa aimed to simulate metasomatic transformation of the fertile mantle caused by fluids and melts released from the subducting sediment. A synthetic H2O- and CO2-bearing mixture that corresponds to the average subducting sediment (GLOSS, Plank and Langmuir (1998)) and mineral fractions