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Vol. 7 (2004 year), No. 1

Voloshina Z.M., Karzhavin V.K., Petrov V.P.
Metamorphism conditions and evaluation of fluid mode of the Pansky massive ore-bearing horizon in connection with the PGE mineralization

The paper contains detailed petrogenetic and microsonde mineralogical research of structure of silicate and sulfide mineral phases of the Pansky massive ore-bearing horizon. Mineral paragenesis and typomorphic peculiarities of minerals, crystallization consecution and thermobarometric conditions of formation in the ore-bearing horizon and ore-free rocks have been researched. It has been established that during metamorphism processes the simultaneous change of the rock mineral structure and its fluid component has been taken place. This process carries the unidirectional and consecutive character and is well reproduced by physical and chemical models. These results will help to estimate the role and influence of the Р -Рў parameters and fluid mode on component structure of firm phases and flying components during transformation and localization of platinum metal mineralization.

(in Russian, стр.5, fig. 2, tables. 0, ref 6, MS Word 95, MS Word 95 161 Kb)

Vol. 15 (2012 year), No. 2

Petrovskaya L.S., Bayanova T.B., Petrov V.P.
The Neoarchaean enderbite-granulite complex of the Central Kola block: Stages of evolution (Kola Peninsula)

The paper presents the results of geological-petrological and isotope-geochemical researches of rocks and minerals of the Neoarchaean enderbite-granulite complex (Central Kola block). The results obtained allowed the researchers to determine the sequence of endogenous processes, P-T conditions and duration of the enderbite-granulite complex evolution within 2.73-1.81 Ga. Three stages of metamorphism have been established in gneisses of the Kola Group: (I) – early granulitic (2.73-2.72 Ga); (II) – superimposed amphibolite facies (2.57-2.55 Ga); (III) – retrograde low-temperature amphibolite facies (2.54 Ga). Stages I and II were separated by emplacement of enderbites (2.66 Ga) and formation of cummingtonite-biotite orthogneisses after enderbites (2.64 Ga). Ultrametamorphism in gneisses of the Kola Group was accompanied by injections of anatectic veins of microcline-plagioclase granite with garnet and sillimanite (2.55 Ga). The tectonomagmatic activity in this region culminated by the injection of veined leucogranites (ca. 2.50 Ga) that crosscut gneisses of the Kola Group, enderbite and cummingtonite-biotite orthogneisses. Based on Sm-Nd and Rb-Sr methods, the influence of Paleoproterozoic processes on the granulite-enderbite complex with the alteration of isotopic systems is recorded at 2.50 and 1.81 Ga ago.

(in English, стр.8, fig. 9, tables. 0, ref 19, Adobe PDF, Adobe PDF 0 Kb)