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Vol. 3 (2000 year), No. 2

Ivanov A.A., Glaznev V.N., Osipenko L.G., Martynov E.V., Kozlov N.E.
Early Precambrian continental accretion on the European part of the North-Atlantic region: Petrochemical and geophysical data

In the paper the possible process of the crusting in the investigated region has been considered within the framework of a single geodynamic model on the basis of the petrogeochemical and geophysical data. The results allow to speak about the accretion growth of the early Precambrian crust, since the formation of the most ancient complexes.

(in Russian, стр.8, fig. 11, tables. 0, ref 39, MS Word 95, MS Word 95 468 Kb)

Vol. 12 (2009 year), No. 3

Sorokhtin N.O., Kozlov N.E., Martynov E.V., Kozlova N.E.
The Late Archaean comatiites: Certain aspects of ore content

Boninites are characterised by a great range of variety and they cannot be practically compared with igneous rocks like picrites, picrite-basalts, basalts, andesites, dacite, and rhyolites. This feature is conditioned by the presence of non-equilibrium phases: quarts-normative matrix and olivine impregnation. Abundance ratio and composition of non-equilibrium phases may be different, and that causes the variety of boninites. The boninite magmas were probably generated by the process of fractional crystallisation of high-magnesium picrite and picrite-basalt melts in subvolcanic conditions. It is necessary for the formation of boninites magmas that the eruption of magma was occurred at a definite stage of crystallisation before olivine separation.

(in Russian, стр.9, fig. 6, tables. 3, ref 20, Adobe PDF, Adobe PDF 0 Kb)

Vol. 15 (2012 year), No. 2

Balashov Yu.A., Martynov E.V.
Correlation of oxygen fugacity in the mantle lithosphere between Ce+4/Ce+3 relation of zircons and petrological buffer FMQ

The paper presents variations of Ce+4/Ce+3 and Eu+3/Eu+2 in zircons from different mantle rocks of the lithosphere. The ratio Ce+4/Ce+3 reflects the "oxidation" degree of the zircon (and rock) formation and Eu+3/Eu+2 – "reducing" properties of the source which allows one to control the level of the oxygen fugacity. A correlation of the ratio Ce+4/Ce+3 in zircons ("geochemical buffer" – "CeB") and petrological buffer FMQ of rocks in the lithosphere vertical section has been performed. This allows one to determine the boundaries of the "upper" and "lower" parts of the lithosphere and reveal the similarity of the variation range of the oxygen fugacity in the upper lithosphere and analogous parameters of the crustal rocks of different age. Besides it helps to establish unique reducing parameters for oxygen in the foot part of the lithosphere.

(in English, стр.19, fig. 13, tables. 4, ref 50, Adobe PDF, Adobe PDF 0 Kb)