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Krivolutskaya N.A.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Smol'kin V.F.,Vernadsky State Geological Museum | Svirskaya N.M.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Mamontov V.P.,OAO Murmanskaya GRE | And 3 more authors.
Geochemistry International | Year: 2010

The comparative-geochemical study was first conducted for the ultrabasic-basic massifs of the central part of the Belomorian mobile belt, which were previously ascribed to the drusite complex on the basis of the presence of coronal textures. The studied magmatic bodies are geochemically heterogeneous and can be subdivided into three groups: (1) high-Mg rocks (MgO > 20 wt %) with elevated Cr content, enriched trace element patterns, and deep negative Ta-Nb anomaly (Sorkajoki Massif). Intrusions of this group are geochemically close to the layered plutons of Northern and Eastern Karelia (Kivakka, Burakovsky) and to the intrusions of the Kola Peninsula (Monchepluton and others); (2) low-Mg intrusions (MgO < 10 wt %) with elevated contents of Fe, Ti, and P (403-m Height Massif). The rocks composing these intrusions are characterized by subhorizontal trace element patterns and weak Ta-Nb anomaly; (3) intrusions with intermediate MgO contents (10-20 wt %), flat, occasionally depleted REE patterns, and lack of Ta-Nb anomaly (Mt. Grob Tundra). The identified geochemical differences do not depend on the degree of metamorphic transformations, but were presumably caused by differences in phase and chemical composition of parental magmas, as well as by conditions of their crystallization. It was substantiated that ultrabasic-basic massifs presently united into the drusite complex are genetically diverse and acquired similar textural appearance due to regional metamorphism. Thus, the presence of coronal textures is insufficient to ascribe the intrusions to the drusite complex, their mineralogical and geochemical composition should be taken into account. © 2010 Pleiades Publishing, Ltd.


Sushchevskaya N.M.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Peyve A.A.,Russian Academy of Sciences | Belyatsky B.V.,All Russia Research Institute of Geology and Mineral Resources of the World Ocean VNIIOkeanologiya
Geochemistry International | Year: 2010

New petrological and geochemical data were obtained for basalts recovered during cruise 24 of the R/V "Akademik Nikolay Strakhov" in 2006. These results significantly contributed to the understanding of the formation of tholeiitic magmatism at the northern end of the Knipovich Ridge of the Polar Atlantic. Dredging was performed for the first time both in the rift valley and on the flanks of the ridge. It showed that the conditions of magmatism have not changed since at least 10 Ma. The basalts correspond to slightly enriched tholeiites, whose primary melts were derived at the shallowest levels and were enriched in Na and depleted in Fe (Na-TOR type). The most enriched basalts are typical of the earlier stages of the opening and were found on the flanks of the ridge in its northernmost part. Variations in the ratios of Sr, Nd, and Pb isotopes and lithophile elements allowed us to conclude that the primary melts generated beneath the spreading zone of the Knipovich Ridge were modified by the addition of the enriched component that was present both in the Neogene and Quaternary basalts of Spitsbergen Island. Compared with the primitive mantle, the extruding magmas were characterized by positive Nb and Zr anomalies and a negative Th anomaly. The formation of primary melts involved melting of the metasomatized depleted mantle reservoir that appeared during the early stages of opening of the Norwegian-Greenland Basin and transformation of the paleo-Spitsbergen Fault into the Knipovich spreading ridge, which was accompanied by magmatism in western Spitsbergen during its separation from the northern part of Greenland. © Pleiades Publishing, Ltd. 2010.


Krivolutskaya N.A.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Belyatsky B.V.,All Russia Research Institute of Geology and Mineral Resources of the World Ocean VNIIOkeanologiya | Smolkin V.F.,Russian Academy of Sciences | Mamontov V.P.,Murmansk Geological Exploration OJSC | And 2 more authors.
Geochemistry International | Year: 2010

First isotopic-geochemical data were obtained on basite-ultrabasite rocks from the southern Kovdor area that were previously provisionally ascribed to the drusite (coronite) complex based on the occurrence of drusite (coronite) textures. The mineral and whole-rock Sm-Nd isochron age determined for five rock samples from the Sorkajoki and Poioiva massifs and the massif of Elevation 403 m turned out to be close (within the error): 2485 ± 51, 2509 ± 93, and 2517 ± 75 Ma, respectively. The crystallization age was evaluated for the two massifs (Poiojovski and Mount Krutaya Vostochnaya) by the U-Pb system of zircons. Our samples contained both magmatic and xenogenic crustal zircons, whose age was estimated at 2700 Ma. The crystallization age of the massifs themselves (data on the magmatic zircons) is 2410 ± 10 Ma. The undepleted character of the mantle source (εNd = +0.9) and the much younger age of the massifs than that of other known manifestations of ultrabasic magmatism in the territory of Karelia and the Kola Peninsula (including the layered pluton classic drusite massifs) suggest that the central part of the Belomorian Mobile Belt hosts one more independent intrusive rock complex, which has never been recognized previously and which is different from typical drusites. © 2010 Pleiades Publishing, Ltd.


Semenov V.S.,Russian Academy of Sciences | Mikhailov V.M.,All Russia Research Institute of Geology and Mineral Resources of the World Ocean VNIIOkeanologiya | Koptev-Dvornikov E.V.,Moscow State University | Ford A.B.,U.S. Geological Survey | And 3 more authors.
Petrology | Year: 2014

The paper addresses the current understanding of the inner structure of the layered intrusions at Dufek Massif in the Pensacola Mountains and the Utpostane and Muren intrusions in Queen Maud Land, Antarctica, which are still poorly known to Russian geologists. The magmatic events at approximately 180 Ma, including the emplacement of layered intrusions, are thought to had predated the breakup of the Gondwana supercontinent. The spatiotemporal similarities of the intrusions determine the importance of the problem of whether they were produced by a single or more than one parental magmas, which are thought to have been derived under the effect of a superplume. © 2014, Pleiades Publishing, Ltd.


Sushchevskaya N.M.,RAS Vernadsky Institute of Geochemistry and Analytical Chemistry | Peyve A.A.,Russian Academy of Sciences | Belyatsky B.V.,All Russia Research Institute of Geology and Mineral Resources of the World Ocean VNIIOkeanologiya
Geochemistry International | Year: 2011

Based on the investigation of samples recovered during Cruise 25 of the R/V "Akademik Nikolai Strakhov," the character of magmatism was determined in the flank parts of the rift zone at the 74°05′N and 73°50′N region, where the direction of the rift valley changes from the north-northwest in the Knipovich Ridge to the northeast-trending structures of the Mohns Ridge. It was shown that the tholeiitic magmas of this region shows all the geochemical characteristics of TOR-2, which is typical of the Mohns Ridge and most oceanic rift zones worldwide, and differ from the basalts of the Knipovich Ridge, which are assigned to a shallower type of tholeiitic magmatism (Na-TOR). The persistent depletion of the magmas in terms of lithophile element contents and radiogenic isotope ratios of Sr, Nd, and Pb reflects the conditions of their formation during the ascent of the depleted oceanic mantle, which has occurred without significant complications since the early stages of the formation of the Mohns Ridge. © 2011 Pleiades Publishing, Ltd.

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