Papers by Evgenii. V Sharkov
International Geology Review, 1972
The Cenozoic (mostly Neogene) volcanic activity in Syria is part of the extensive magmatism that ... more The Cenozoic (mostly Neogene) volcanic activity in Syria is part of the extensive magmatism that took place in the Mashrek Region, Middle East, from upper Eocene to Holocene (∼40–0.0005 Ma). Samples in western Syria are mostly high TiO 2 (TiO 2 ∼1.8–3.7 wt.%) alkaline mafic rocks (basanites, hawaiites and alkali basalts) plus rare transitional/tholeiitic basalts and basaltic andesites) with within-plate-like trace element signature. On the basis of incompatible trace element content, the volcanic activity in Syria has been divided into two stages: the first lasting from ∼25 to ∼5 Ma and the second from ∼5 to recent times. Indeed, the Syrian lavas show incompatible trace element content increasing with decreasing age from ∼25 to ∼5 Ma, followed by an abrupt decrease to low values roughly at the Miocene–Pliocene boundary. This temporal shift in composition is related to major tectonic reorganization occurred during upper Miocene. The proposed petrogenetic model invokes three steps: (a) passive upwelling of the shallow asthenosphere during the development of the Dead Sea transform fault system. Different degrees of partial melting were followed by variable extents of fractional crystallization and limited upper crustal contamination; (b) the Miocene–Pliocene boundary tectonic change enhanced passive decompression of the same sources and a consequent increase in degree of partial melting resulting in low incompatible trace element content of the relatively high-volume liquids; (c) after this phase, the incompatible trace element content in the basaltic magmas increased as consequence of fractional crystallization processes. Major and trace element content similarities with the rest of the circum-Mediterranean igneous rocks are consistent with a common relatively shallow origin for the Cenozoic anorogenic magmatism of the entire circum-Mediterranean area (the so-called Common Magmatic Reservoir). Because much of the igneous activity in the studied area is concentrated near the Dead Sea fault, the origin of Cenozoic magmatism in Syria (and in the rest of the circum-Mediterranean area) reflects a strong lithospheric control on the loci of partial melting. Mantle plumes from lower mantle and/or north-westward channelling of the Afar mantle plume is not needed to explain volcanic activity in Syria and the Mashrek area.
Lithos, 1995
Lower crustal xenoliths entrained in a Paleozoic ultramafic lamprophyre breccia pipe on Elovy isl... more Lower crustal xenoliths entrained in a Paleozoic ultramafic lamprophyre breccia pipe on Elovy island, Kola peninsula, Russia, represent some of the oldest lower crustal material yet investigated from Europe. The xenoliths vary from feldspar-poor, gametrich rocks which resemble eclogites, to feldspar-rich garnet granulites. Quartz-rich felsic granulites, as well as pyroxenites and amphibole-rich rocks are also present.
A new type of sulfide occurrence related to metasomatically altered brecciated gabbroids has been... more A new type of sulfide occurrence related to metasomatically altered brecciated gabbroids has been studied at the Sierra Leone site situated in the axial rift valley of the Mid-Atlantic Ridge (Markov Deep, 6 ° N). Two associations of plutonic, subvolcanic, and volcanic rocks were dredged: (1) mid-ocean ridge basalts (MORB) and their intrusive analogues and (2) rocks of the silicic Fe-Ti-oxide series with dominating gabbronorites and sporadic trondhjemites. Almost all igneous rocks at the Sierra Leone site are enriched in Pb, Cu, U, Ga, Ta, Nb, Cs, and Rb and depleted in Zr, Th, and Hf. The rocks of the Fe-Ti-oxide series are enriched in Zn, Sn, and Mo and depleted in Ni and Cr. The main ore-bearing zone is situated at the foot of the eastern wall of the deep, where it is hosted in cataclastic hornblende gabbro and gabbronorite of the Fe-Ti-oxide series. Ore mineralization in metasomatically altered rocks is composed of quartz-sulfide and prehnite-sulfide veinlets, disseminated sulfide, and veined copper sulfide ore. The ore consists of pyrite, chalcopyrite, sphalerite, pyrrhotite, bornite, chalcocite, and digenite. The δ 34 S value of sulfides varies from 3.0 to 15.3‰. At the foot of the eastern wall of the Markov Deep, directly downslope from the ore-bearing zone, loose sediments contain grains of native Cu, Pb, Zn, and Sn and intermetallic compounds (isoferroplatinum, tetraferroplatinum, and brass) apparently derived from the ore. Mineral assemblages of ore-bearing metasomatic rocks and fluid inclusions therein were studied. Ore metasomatism developed under a low oxygen potential within a temperature interval from 400 to 160 ° C, though initial hydrothermal alteration of rocks proceeded at temperatures of 800-450 ° C. The temperature of stringer-disseminated ore mineralization is estimated at 170-280 ° C. The hydrothermal fluids are considered to be of magmatic origin; as the hydrothermal system evolved, they became diluted with seawater that was contained in fractured oceanic crust. The ore matter could have been derived from magmatic fluids that were released from water-saturated melts of the Fe-Ti oxide series during their ascent and leached from host gabbroids in the process of metasomatic alteration.
Radiophysics and Quantum Electronics, 1981
Radiophysics and Quantum Electronics, 1979
... i. NA Armand, AE Basharinov, and AM Shutko, Izv. Vyssh. Uchebn. Zaved., Radiofiz., 20, No. 6,... more ... i. NA Armand, AE Basharinov, and AM Shutko, Izv. Vyssh. Uchebn. Zaved., Radiofiz., 20, No. 6, 809 (1977). ... 5. VA Rabinovich and Z. Ya. Khavin, Brief Chemical Handbook [in Russian], Khimiya, Moscow (1977). 6. VR Amirkhanyan, EA Bespalova, MG Bulatov, et al., Tr. Glav. ...
In the April 2001 both two important magnetospheric storms (Dst > 200 ? ) and some? small geom... more In the April 2001 both two important magnetospheric storms (Dst > 200 ? ) and some? small geomagnetic field disturbances were registered. In our report to COSPAR-2000 in Warsaw we informed about revelation of statistic correlation among magnetospheric processes and global tropical cyclogenesis in 1999-2000. As the atmosphere-ocean global system tropical zone plays an important role both in dynamics and evolution of synoptic and climatic processes occuring in the Earth's atmosphere, looking for their energetic sources which are external ones as regards the atmosphere-ocean system is very essential. The goal of the paper is to discuss both energetic characteristics of magnetospheric storms and their connection with global tropical cyclogenesis in the April 2001.
Izvestiya, Atmospheric and Oceanic Physics, 2013
ABSTRACT The trajectory characteristics and the intensity evolution of the Alberto tropical cyclo... more ABSTRACT The trajectory characteristics and the intensity evolution of the Alberto tropical cyclone (TC) in the integral water-vapor field are analyzed in detail using a software-algorithmic complex designed for constructing highly detailed global radio-thermal fields of the ocean-atmosphere system based on microwave satellite measurements. This complex was developed by the authors earlier and allows one to obtain global animated radio-thermal fields with a time step of 1.5 h and a spatial resolution of 0.2°. Special attention is paid to the problem of revealing the energy sources of three consecutive intensifications of this TC. The analysis of satellite data with the use of the animation method developed by the authors shows for the first time that these sources are regions with an increased (exceeding the critical level) integral water-vapor content located in different geographical areas lying along the complex trajectory of the TC with a variable intensity. The first region was located in the equatorial intertropical convergence zone, the second was located above the Gulf Stream water area, and the third resided in the area affected by the Azores High.
Izvestiya, Atmospheric and Oceanic Physics, 2011
On the basis of simultaneous rocket soundings of the middle atmosphere and lower ionosphere from ... more On the basis of simultaneous rocket soundings of the middle atmosphere and lower ionosphere from the rocket testing ground at Thumba (8 0N, 770 E, India), and remotely sensed observations for tropical cyclones (performed over North Indian and the West North Pacific Oceans), the possibility of influence of tropical cyclones on processes in middle atmosphere and the lower ionosphere is shown. In turn essential influences on both atmosphere and ionosphere are caused by solar activity. In this paper the different role of solar activity influence on the ionosphere in the presence of tropical cyclones and in days without them is shown. Possible mechanisms of this influence are discussed.
Geoscience Frontiers, 2015
East European Craton Calc-alkaline and shoshonite-latite volcanism Mantle plume head Basaltic pla... more East European Craton Calc-alkaline and shoshonite-latite volcanism Mantle plume head Basaltic plateaus Plume-crust interaction Tectonic "diffluence" a b s t r a c t
Geochemistry International
The vertical cross section and evolution of the major mineral phases were studied in the Layered ... more The vertical cross section and evolution of the major mineral phases were studied in the Layered complex of the Late Devonian Voikar ophiolite association. The complex consists of two megarhythms separated by a transitional zone. The megarhythms are similar in structure and are characterized by a gradation from ultrabasic rocks at the bottom to gabbroids at the top. The Upper megarhythm differs from the Lower one owing to the occurrence of orthopyroxene in the gabbroids. The Transitional zone between the megarhythms has the reverse sequence (grading upsection from basic to ultrabasic rocks). Based on this study and previous isotopic data [1, 2], we concluded that the parental magmas of the Lower megarhythm were derived from a slightly depleted mantle source, similarly to rocks of the ultrabasic complex of this association. The magmas of the Upper megarhythm were derived from a more depleted mantle and were contributed by an ancient material from a subducted plate or mixed with subduction-related magmas. We suggest that the Layered complex represents a well-preserved fragment of the lower crust in the back-arc setting. This crustal domain originated from intrusions of newly formed magmas along the crust-mantle boundary. The formation of the lower crust was accompanied by the spreading of the mantle plume head, which resulted in the shearing of mantle peridotites and the overlying newly formed hot cumulates. In terms of geodynamics, the first stage of the formation of the Voikar ophiolites was related to the opening of a back-arc basin, while the second stage reflected the initiation and evolution of a subduction zone.
Geochemistry International
Geological and petrological study of the evolution of the Earth and Moon, as well as data on Venu... more Geological and petrological study of the evolution of the Earth and Moon, as well as data on Venus and Mars, showed that all solid terrestrial planets presumably were initially heterogeneous and developed according to a common scenario, which involved gradual heating of their interiors up to the formation of a liquid core and associated gradual cooling of their outer shells. Such a character of heating was supposedly provided by a wave of centripetal deformations, which arise in a rotating body. At the first phase of evolution, tectonomagmatic processes were related to the ascent of superplumes formed in a depleted mantle. The appearance of liquid cores initiated the ascent of geochemically enriched superplumes of the second generation from the core-mantle boundary. They reached moderate depths, and the spread of their heads led to a fundamental reconstruction of planetary surfaces.
Russian Geology and Geophysics
Doklady Earth Sciences
Since Early Precambrian volcanic rocks are typically strongly altered by superimposed processes, ... more Since Early Precambrian volcanic rocks are typically strongly altered by superimposed processes, they retain primary composition and texture only in exceptional cases. Such a case is observed in the Early Paleoproterozoic volcanic rocks of the Vetrenyi Belt Formation of the synonymous riftogenic structure in southeastern Karelia, where volcanic glass is locally preserved . The Sm-Nd, Re-Os, and U-Pb (zircon) ages of volcanic rocks of this formation range from 2.5 Ga in the lower parts to 2.41 Ga in the upper parts of the sequence [1-3].
Instruments and Methods for Astrobiology and Planetary Missions XII, 2009
Microbial complexes were identified in the volcanic glasses from the ancient (2.4-Ga basaltic pil... more Microbial complexes were identified in the volcanic glasses from the ancient (2.4-Ga basaltic pillow-lavas of Karelia) and modern (pillow lavas of the Mid-Atlantic ridge) volcanic rocks. It was shown that their microbial colonization is likely to occur by the same mechanism. Thus, well preserved pillow lavas, which occupy spacious fields in the Archaean and Early Paleoproterozoic greenstone belts, are promising objects for the search for the earliest traces of life on Earth.
Petrology
First data are presented on vein granophyric granites from Europe's largest Early Paleoproterozoi... more First data are presented on vein granophyric granites from Europe's largest Early Paleoproterozoic Burakovskii layered mafic-ultramafic pluton, Southern Karelia. The pluton consists of two individual bodies: Aganozero and Shalozero-Burakovskii. Granites were found only in the latter. They are confined mainly to the Pigeonite Gabbronorite Zone and practically do not occur in other zones. The veins show abrupt contacts without chill zones. The granites range from leucogranodiorite to potassium leucogranite. Their texture is strongly variable from hypidiomorphic to granophyric. In terms of geologic and compositional features, these rocks are classified with transgressive granites of layered intrusions. The vein granites of the Burakovskii Massif belong to the calc-alkaline series and continue the trend of mafic rocks from the intrusion with a gap at SiO 2 = 59-65 wt %. The ε Nd values of the granites vary slightly, from -2.4 to -3.7, and are very close to those of the pyroxenites and pigeonite gabbronorites of the Shalozero-Burakovskii intrusion (from -1.4 to -3.0), but differ sharply from those of the enclosing Archean rocks (from -5.7 to -10.7). These facts are inconsistent with granite generation through basement melting and suggest a single source for the granites and mafic rocks. Based on the negative ε Nd values, this source was contaminated by crustal material. The geologic, petrological, and isotope geochemical data indicate that the vein granites were coeval to grabbroids and formed in situ within the Pigeonite Gabbronorite Zone enriched in quartz-feldspar intercumulus material. It is suggested that the granites were formed from residual intergranular acid melt, which preserved in almost completely solidified cumulates of this zone. The contraction led to vacuum extraction of the melt into shrinkage fractures. In the largest fractures, the separated granite melt experienced subsequent differentiation up to hyperacid varieties. The independence of contraction phenomena and melt evolution in the intergranular space could be responsible for the compositional gap between mafic and acid rocks.
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Papers by Evgenii. V Sharkov