Description:    The Dhofar 280 lunar highland meteorite is the first one in which native silicon was identified in association with iron silicides. This association is surrounded by silicate material enriched in Si, Na, K, and S and occurs within an impact-melt matrix. Compared to the meteorite matrix, the objects with native Si and the silicate material around them show high Al-normalized concentrations of volatile elements and/or elements with low sensitivity to oxygen but are not any significantly enriched in refractory lithophile elements. Some lithophile elements (V, U, Sm, Eu, and Yb) seem to be contained in reduced forms, and this predetermines REE proportions atypical of lunar rocks and a very low Th/U ratio. The admixture of siderophile elements (Ni, Co, Ge, and Sb) suggests that the Si-bearing objects were contaminated with meteorite material and were produced by the impact reworking of lunar rocks. The high concentrations of volatile elements suggest that the genesis of these objects could be related to the condensation of silicate vapor generated during meteorite impacts. The reduction of silicon and other elements could take place in an impact vapor cloud, with the subsequent condensation of these elements together with volatile components. On the other hand, condensates of silicate vapor could be reduced by impact reworking of impact breccias. Impact-induced vaporization and condensation seem not to play any significant role in forming the composition of the lunar crust, but the contents of the products of such processes can be locally relatively high. The greatest amounts of silicate vapor were generated during significant impact events. For example, more than 70% of the total mass of lunar material evaporated in the course of impact events should have resulted from the collision of the Moon with a cosmic body that produced the Moon’s largest South Pole-Aitken basin. Content Type Journal Article Pages 506-519 DOI 10.1134/S0869591112060021 Authors M. A. Nazarov, Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991 Russia S. I. Demidova, Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991 Russia M. O. Anosova, Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991 Russia Yu. A. Kostitsyn, Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991 Russia Th. Ntaflos, Departament für Lithosphärenforschung, Universittät Wien, Althanstrasse 14, 1090 Wien, Österreich F. Brandstaetter, Naturhistorisches Museum, Burging 7, A-1014 Wien, Österreich Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 6

Description:    The results of study of chemical composition, mineral-forming medium, P - T conditions of crystallization, and the age characteristics of subvolcanic felsic rocks that are spatially associated with rare-metal granite massifs in the ore units of Transbaikalia (Sherlovaya Gora, Khangilay, Bukuka, Belukha, and Shumilovka) give grounds for defining cogenetic volcanoplutonic associations. These associations within the studied region consist of rare-metal granites, ongonites, rhyolites, ongorhyolites, and trachyrhyodacites, which have much in common, but also many differences. The common chemical features of these rocks are their peraluminium signature, low mafic index and basicity, as well as enrichment (as compared to crust) in trace lithophile elements (Li, Rb, Nb, Ta, Sn, W, and F), the low contents of Zr, REE, and Sr, and the similar distribution of trace and refractory elements. At the same time, these rocks differ in the proportions of sodium and potassium, levels of concentrations of lithophile trace and refractory elements, REE distribution patterns, P - T regimes of crystallization, and the volatile composition. The composition of melts from all types of the studied rocks and trace element distribution between melts and rocks were studied on the basis of ion-microprobe analysis of rehomogenized glasses of melt inclusions in quartz. The highest concentrations of lithophile trace elements in the melt, including Cs (up to 300 ppm), Rb (up to 1002 ppm), U (up to 42 ppm), and Th, were found in the trachyrhyodacites of the Bukuka-Belukha ore unit; in terms of Li content this melt is comparable with the Ary-Bulak ongonites (690 and 715 ppm Li, respectively), and differ by an order of magnitude in the contents of refractory and rare-earth elements (total REE 94.4 and 5.44 ppm, respectively), which is indicative of a lower differentiation degree of this melt as compared to ongonites. Potassic rhyolites are peculiar in the low content of lithophile trace elements, but residual melt reveals notable enrichment in Li (up to 130 ppm) and Nb (up to 120 ppm). The accumulation of U in the residual melt of the trachyrhyodacitic and rhyolitic magmas of Eastern Transbaikalia may indicate their high potential for postmagmatic uranium ore formation. Isotope-geochronological studies (Rb-Sr isotope system) of the Sherlovaya Gora ore unit showed that the entire complex of volcanoplutonic association (granites, ongonites, rhyolites, and ongorhyolites) formed almost simultaneously within an interval of 4 Ma: from 145.7 ± 1.3 Ma at IR Sr = 0.70507 ± 20 and MSWD = 0.48 to 141.5 ± 1.0 Ma at IR Sr = 0.70359 ± 63 Ma and MSWD = 0.24. A spatial association of the subvolcanic rock complex with rare-metal granite massifs, their formation within a common age interval, geochemical features, and P - T conditions of crystallization suggest that they are genetically related but were derived from variably evolved sources, which originated from a single protolith under the action of mantle plume that existed beneath Central Asia at that time (Yarmolyuk and Kovalenko, 2003). Content Type Journal Article Pages 567-592 DOI 10.1134/S0869591112060057 Authors L. F. Syritso, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, 199034 Russia E. V. Badanina, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, 199034 Russia V. S. Abushkevich, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia E. V. Volkova, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, 199034 Russia E. V. Shuklina, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, 199034 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 6

Description:    Practically all of the examined spherules extracted in 1948–1949 from soil at the crater field of the 1947 Sikhote Alin meteorite shower are ablation spherules produced during this meteorite fall. The spherules can classified into two textural types: (i) fine-grained, which consist of Ni-bearing magnetite (3–6 wt % NiO) dendrites, sometimes with minor amounts of interstitial P- and Fe-rich material, and (ii) coarse-grained, which also consist of Ni-bearing magnetite dendrites or grains, sometimes with wuestite, an interstitial material, which resembles that in type (i) or has a silicate composition. The texture, mineralogy, and chemistry (presence of P and Si) of these spherules differ from those of iron cosmic spherules (type I) that occur in the background flux of micrometeorites. The spherules are thought to were produced by the ablation of meteoritic material at elevations of about 12 km (in the region where disintegration starts) and below, at maximum temperatures of 1600–2180°C and oxygen fugacity of 10 −14 to 10 −1 atm. Conceivably, the ablated material was enriched in silicates compared to the fallen material. Content Type Journal Article Pages 520-528 DOI 10.1134/S086959111206001X Authors D. D. Badyukov, Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119991 Russia J. Raitala, Astronomy, Department of Physical Sciences, University of Oulu, P.O. Box 3000, FIN-90014 Oulu, Finland Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 6

Description:    The Piaoak tin-bearing granite-leucogranites located in the Caobang Province of Northern Vietnam compose a stock-like hypabyssal body. Host rocks are represented by Early Devonian carbonate sequences and Early Triassic “black” shales. The geochronological age of the Piaoak granite-leucogranites corresponds to the Late Cretaceous: T = 83.5 ± 6.2 Ma, 87 Rb/ 86 Sr method; T = 89.7 ± 1.0 Ma, 39 Ar/ 40 Ar method. The massif has a simple basic to acid order: two-mica and muscovite granite-leucogranite → raremetal aplites, pegmatites → tin-bearing greisens and hydrothermal veins. The petrographic and microstructural studies revealed a sharp change in crystallization conditions of the granite-leucogranite magma at the late magmatic stage and formation of muscovite via incongruent melting of protolithionite. The study of melt and coexisting fluid inclusions showed that solidus crystallization occurred under fluid-saturated conditions at 635–600°C. In composition, the granite-leucogranites of the Piaoak Massif correspond to the raremetal-plumasite geochemical type (according to L.V. Tauson), and reach Li-F facies in terms of their rare-element composition. The composition of aplites and pegmatites demonstrates that granite-leucogranite magma did not accumulate lithophile and volatile components in the residual melt during differentiation, but was initially enriched in rare-metals. It is most probable that the melt was generated from Proterozoic lithotectonic complexes and overlaying Lower Triassic “black” shales. Content Type Journal Article Pages 545-566 DOI 10.1134/S0869591112050074 Authors A. G. Vladimirov, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia Phan Luu Anh, Institute of Geological Sciences, Vietnam Academy of Sciences and Technologies, Hanoi, Vietnam N. N. Kruk, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia C. Z. Smirnov, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia I. Yu. Annikova, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia G. G. Pavlova, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia M. L. Kuibida, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia E. N. Moroz, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia E. N. Sokolova, Sobolev Institute of Geology and Mineralogy, Siberian Branch, Russian Academy of Sciences, pr. Akad. Koptyuga, Novosibirsk, 630090 Russia E. I. Astrelina, Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 6

Description:    A new method of isotope geochronology was proposed for dating native platinum minerals on the basis of the α-decay of the natural isotope 190 Pt. The analysis of the thermal desorption of helium in the crystal lattice of native metals, including platinum, allowed us to predict a very high thermal stability (retentivity) of radiogenic 4 He in native platinum minerals up to their melting temperatures. In order to validate the proposed 190 Pt- 4 He method, direct isotopic dating was performed for isoferroplatinum from the Galmoenan dunite-clinopyroxenite and Kondyor alkaline ultramafic massifs. The results of dating obtained by this method for primary ore platinum from the Galmoenan Massif (70 ± 5 Ma) are consistent with geological observations and mean Sm-Nd and Rb-Sr isotopic age estimates. The 190 Pt- 4 He age obtained for placer isoferroplatinum from the Kondyor Massif (112 ± 7 Ma) also agrees with geological observations and is close to the K-Ar and Rb-Sr ages of koswites (phlogopite-magnetite pyroxenites, gabbros, nepheline syenites, and metasomatic rocks after dunites). Our experimental data demonstrated that the 190 Pt- 4 He method is a promising tool for dating native platinum minerals. Content Type Journal Article Pages 491-505 DOI 10.1134/S0869591112060033 Authors Yu. A. Shukolyukov, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia O. V. Yakubovich, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia A. G. Mochalov, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia A. B. Kotov, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia E. B. Sal’nikova, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia S. Z. Yakovleva, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia S. I. Korneev, Faculty of Geology, St. Petersburg State University, Universitetskaya nab. 7/9, St. Petersburg, 199042 Russia B. M. Gorokhovskii, Institute of Precambrian Geology and Geochronology, Russian Academy of Sciences, nab. Makarova 2, St. Petersburg, 199034 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 6

Description:    Melt inclusions were investigated in olivine phenocrysts from the New Caledonia boninites depleted in CaO and TiO 2 and enriched in SiO 2 and MgO. The rocks are composed of olivine and pyroxene phenocrysts in a glassy groundmass. The olivine phenocrysts contain melt inclusions consisting of glass, a fluid vesicle, and daughter olivine and orthopyroxene crystals. The daughter minerals are completely resorbed in the melt at 1200–1300°C, whereas the complete dissolution of the fluid phase was not attained in our heating experiments. The compositions of reheated and naturally quenched melt inclusions, as well as groundmass glasses were determined by electron microprobe analysis and secondary ion mass spectrometry. Partly homogenized melts (with gas) contain 12–16 wt % MgO. The glasses of inclusions and groundmass are significantly different in H 2 O content: up to 2 wt % in the glasses of reheated inclusions, up to 4 wt % in naturally quenched inclusions, and 6–8 wt % in groundmass glasses. A detailed investigation revealed a peculiar zoning in olivine: its Mg/(Mg + Fe) ratio increased in a zone directly adjacent to the glass of inclusions. This effect is probably related to partial water (hydrogen) loss and Fe oxidation after inclusion entrapment. The numerical modeling of such a process showed that the water loss was no higher than a few tenths of percent and could not be responsible for the considerable difference between the compositions of inclusions and groundmass glasses. It is suggested that the latter were enriched in H 2 O after the complete solidification of the rock owing to interaction with seawater. Based on the obtained data, the compositions of primary boninite magmas were estimated, and it was supposed that variations in melt composition were related not only to olivine and pyroxene fractionation from a single primary melt but also to different degrees and (or) depths of magma derivation. Content Type Journal Article Pages 529-544 DOI 10.1134/S0869591112060045 Authors I. P. Solovova, Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 119017 Russia D. Ohnenstetter, CRPG, CNRS, F-54501 Vandoeuvre lès Nancy, France A. V. Girnis, Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 119017 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 6

Description:    The Early Paleoproterozoic Monchegorsk Complex is exposed over an area of 550 km 2 and comprises two layered mafite-ultramafite intrusions of different age: the Monchegorsk pluton of ultramafic and mafic rocks and the predominantly gabbroid Main Range Massif (also referred to as the Moncha-Chuna-Volch’i Tundras Massif), which are separated by a fault. Both massifs consists of intercalating cumulates (first of all, Ol ± Crt , Ol + Opx ± Crt , Opx, Opx + Pl ± Cpx , and Pl ), they were produced by similar melts of siliceous high-Mg series but differ in the stratigraphy of their cumulates: while the Monchegorsk pluton is dominated by ultramafites, the Main Range Massif consists mostly of gabbroids, first of all, of gabbronorites. The complex is accompanied by PGE-Cu-Ni ore mineralization, low-sulfide Pt-Pd mineralization, and chromite mineralization. Judging from geological data and isotopic dates, the Monchegorsk Complex is a long-lived magmatic center, which evolved over a time span of 50 Myr at 2.50–2.46 Ga. The Main Range Massif is younger and likely truncates the western continuation of the Monchegorsk pluton. The complex is spatially restricted to the zone of the Middle Paleoproterozoic regional Central Kola Fault and is now tectonic collage whose rocks were variably affected by overprinted metamorphism in the course of deformations. These processes most significantly affected rocks along the peripheries of the Monchegorsk pluton in the south. These rocks were completely transformed under greenschist-facies conditions but often preserved their primary textures and structures. The processes overprinted both the marginal portions of the pluton itself and the rocks of its second phase, which are accompanied by economic low-sulfide PGE deposits. The PGE-Cu-Ni ore mineralization of the Monchegorsk Complex is genetically related to two distinct evolutionary episodes with a quiescence period in between: (1)  The emplacement of large layered mafite-ultramafite intrusions at 2.5–2.45 Ga. Economic deposits of sulfide Cu-Ni ores with subordinate PGE mineralization occur within the Monchegorsk pluton, and the moderate-grade low-sulfide PGE ores are related to its second evolutionary phase (in the foothills of Vuruchuaivench and in the Moroshkovoe Lake, and Southern Sopcha areas). The primary magmatic ore mineralization is predominantly Cu-Fe-Ni sulfide with PGE bismuthides-tellurides. (2)  The Monchegorsk Complex was involved in the zone of the Central Kola Fault at 2.0–1.9 Ga and was broken in a collage of tectonic blocks. The rocks were sheared along the boundaries of the blocks and were affected by overprinted metamorphism, which proceeded under greenschist-facies conditions in the structures surrounding the Monchegorsk pluton in the south. Thereby the primary PGE-Cu-Ni ore mineralization underwent metamorphic processes was recrystallized with the formation of Pt-Pd arsenides, stannides, antimonides, selenides, etc. This processes was associated with the partial redistribution of PGE with their local accumulation (up to economic concentrations), and the orebodies themselves acquired diffuse outlines. In other words, the second episode was marked by the transformation of the older primary magmatic ore mineralization. Content Type Journal Article Pages 607-639 DOI 10.1134/S0869591112070041 Authors E. V. Sharkov, Institute of the Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 109017 Russia A. V. Chistyakov, Institute of the Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 109017 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 7

Description:    The process of CO 2 flashing through hydrous albite-hedenbergite melt was experimentally examined at a temperature of 1100°C and a pressure of 2 kbar. Carbon dioxide was generated when the melt interacted with calcite, and wollastonite was the predominant synthesized phase. Mafic components were introduced into the hydrous albite melt via the dissolution of natural hedenbergite. Raman spectroscopic data on bubbles of the fluid phase in the quench glass indicate that the CO 2 /H 2 O proportions of the bubbles vary. IR spectroscopic data on the glass prove that the water concentration after CO 2 flashing decreased from 5.5 to approximately 3 wt %. The comparison of the composition of the recrystallized clinopyroxene in contact with melt (with and without CO 2 blowing) indicates that CO 2 oxidizes Fe in the melt. The redox effect of CO 2 is quantified by the empirical clinopyroxene tool for metering oxygen fugacity (oxometer), which was calibrated based on experimental data. The oxygen fugacity in our experiments with CO 2 flashing (estimated by the clinopyroxene oxometer) was NNO + (3.0–3.5). Our estimates with the application of the clinopyroxene oxometer indicate that the maximum oxygen fugacity in the magmatic chambers of Vesuvius and Stromboli volcanoes (which are bubbled with CO 2 ) is also close to NNO + (3.5 ± 0.5). Content Type Journal Article Pages 593-606 DOI 10.1134/S0869591112070053 Authors A. G. Simakin, Institute of Experimental Mineralogy, Russian Academy of Sciences, ul. Institutskaya 4, Chernogolovka, Moscow oblast, 142432 Russia T. P. Salova, Institute of Experimental Mineralogy, Russian Academy of Sciences, ul. Institutskaya 4, Chernogolovka, Moscow oblast, 142432 Russia G. V. Bondarenko, Institute of Experimental Mineralogy, Russian Academy of Sciences, ul. Institutskaya 4, Chernogolovka, Moscow oblast, 142432 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 7

Description:    The metapelitic schists of the Golpayegan region can be divided into four groups based on their mineral assemblages: (1) garnet-chloritoid schists, (2) garnet schists, (3) garnet-staurolite schists, and (4) staurolite-kyanite schists. Paleozoic pelagic shales experienced progressive metamorphism and polymetamorphism from greenschist to amphibolite facies along the kyanite geotherm. Mylonitic granites are concentrated in the central part of the region more than in other areas, and formed during the dynamic metamorphic phase by activity on the NW-SE striking Varzaneh and Sfajerd faults. The presence of chloritoid in the metapelites demonstrates low-grade metamorphism in the greenschist facies. The textural and chemical zoning of garnets shows three stages of growth and syntectonic formation. With ongoing metamorphism, staurolite appeared, and the rocks reached amphibolite facies, but the degree of metamorphism did not increase past the kyanite zone. Thus, metamorphism of the pelitic sediments occurred at greenschist to lower amphibolite facies. Thermodynamic studies of these rocks indicate that the metapelites in the north Golpayegan region formed at 511–618°C and 0.24–4.1 kbar. Content Type Journal Article Pages 658-675 DOI 10.1134/S086959111207003X Authors S. Karimi, Department of Geology, University of Isfahan, Hezarjerib Ave Postal Code: 81746-73441 Isfahan, Iran S. M. Tabatabaei Manesh, Department of Geology, University of Isfahan, Hezarjerib Ave Postal Code: 81746-73441 Isfahan, Iran H. Safaei, Department of Geology, University of Isfahan, Hezarjerib Ave Postal Code: 81746-73441 Isfahan, Iran M. Sharifi, Department of Geology, University of Isfahan, Hezarjerib Ave Postal Code: 81746-73441 Isfahan, Iran Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 7

Description:    The Mg-(Fe + Ti)-Al melting diagram for pyrolite based on experimental data from literature shows the composition of the liquid as a function of pressure and the degree of pyrolite melting. Three mechanisms of liquid separation from a mantle source material are discussed: (i) gravitational mechanism, which works at a degree of source material melting of 25%, (ii) filter pressing mechanism, which is efficient at degrees of melting lower than 2%, and (iii) nearly complete local melting of mantle material. Garnet in the solid residue is thought to play an important role by affecting the chemistries of mantle magmas. The comparison of petrochemical and experimental data in a Mg-(Fe + Ti)-Al ternary plot shows that picrite and ferropicrite alcaline primary magmas are segregated at depths of 120 and 210 km, respectively, in the garnet stability zone, at degrees of melting lower than 2%; and tholeiite basalt magmas are segregated above this zone. At degrees of melting of 25%, picrobasalt, komatiite-basalt, picrite, and ferropicrite primary magmas of the tholeiite series are derived at depths of 80, 130, 240, and 300 km, respectively. Ultrabasic komatiite magma is generated at high degrees of mantle source melting, with the solid residues devoid of garnet. The tholeiite basalt series can be produced by two parental melts: aluminous and magnesian basaltic, both separated from the mantle sources via the filter pressing mechanism: the former at depths shallower than 30 km in ocean spreading zones (TOR-2), and the latter at depths of 50–60 km in oceanic spreading zones (TOR-1) and in the subcontinental lithosphere. Primary magnesian basalt magmas of the calc-alkaline and tholeiite series are derived in the lithospheric mantle at the same depths and low degrees of melting. Different evolutionary trajectories of compositionally similar primary magmas are controlled by the conditions of their further fractional crystallization: in compressional environments and with fluids saturating the melts in subduction zones for the former and in extensional environments and free magma ascent to the surface for the latter. Ultrapotassic rock series, such as lamprophyres, leucitites, kamafugites, lamproites, and kimberlites, are most probably generated via the melting of the metasomatized subcratonic mantle. Content Type Journal Article Pages 640-657 DOI 10.1134/S0869591112070028 Authors Zh. A. Fedotov, Geological Institute, Kola Research Center, Russian Academy of Sciences, ul. Fersmana 14, Apatity, Murmansk oblast, 184209 Russia Journal Petrology Online ISSN 1556-2085 Print ISSN 0869-5911 Journal Volume Volume 20 Journal Issue Volume 20, Number 7