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Vol. 5 (2002 year), No. 1

Neradovsky Yu.N., Rundkvist T.V., Galkin A.S. and Kliment'ev V.N.
To the problem of the Sopcha "horizon-330" PGE bearing and its industrial usage (the Monchegorsk pluton)

The new data on the forms of platinum metals' evolution in the "horizon-330" ores have been obtained. The total PGE content is 1-2 ppm. The following PGE mineral phases have been established: merenskite, intermetallic compounds of the (Pd, Pb) and (Pd, Rh, Cu) types and a number of phases incorporated as fine grains in the main sulphide minerals: pyrrhotine, pentlandite and chalkopyrite. The PGE admixtures have been founded in pyrrhotite, chalcosine, pentlandite and heazlewoodite. There are no Pt admixtures in the minerals. It has been noticed that sulphide mineralization in the "horizon-330" ore body is not constant in composition and is linked by the adjacent ore composition. Eastwards ores have become more basic, the olivine content has being decreased, and that leads to the drop of silicate nickel in the "horizon-330" ores and improving of the ore quality.

(in Russian, стр.6, fig. 7, tables. 3, ref 15, MS Word 95, MS Word 95 406 Kb)

Vol. 5 (2002 year), No. 1

Dudkin K.O. and Rundkvist T.V.
On the connection of magnetic anomalies with the distribution of brown plagioclases in the Pansky massif

A correlation between the results of the ground magnetic mapping and the distribution of brown and colourless (in thin sections) plagioclases has been made using a great amount of the geological mapping data. The colour of plagioclase is a result of the admixed magnetite impurity. Brown plagioclases clearly indicate the increased magnetic properties of gabbronorites in the Pansky intrusion. The colourless plagioclases point out the reduced magnetic properties of the rocks. The rocks containing intense brown plagioclases are responsible for the great majority of magnetic anomalies observed over the Pansky intrusion. The rocks containing brown plagioclase form lenses and layers persistent along the strike and dip. The direction of the residual magnetization is consistent with the Svecofennian paleomagnetic Pole (I = 30В°, D = 0В°). This direction of the residual magnetization is predominant for the most part of the Pansky intrusion rocks, though there is a significant dispersion of data determined by the thermo-viscous magnetization.

(in Russian, стр.12, fig. 6, tables. 5, ref 16, MS Word 95, MS Word 95 367 Kb)

Vol. 5 (2002 year), No. 1

Pripachkin P.V. and Rundkvist T.V.
Brown plagioclases in the Fedorova-Pana massif gabbronorites

On the base of the investigation of gabbronorites petrographic textures in the Marjok area it has been established that the rocks containing brown plagioclase (including thin-grained magnetite) are widespread in the alternation zone with the S13, S23, S33 structural types. It has been shown that the plagioclasic claster of the type S33, as a rule, contents higher-magnetic-bearing grains. This observation could not be verified by the "magnetic powdergraphy" method. This method has been found to be insensitive for those forms of small magnetic particles. The connection between textural types and magnetic properties of gabbronorites is important with respect of some new forms of layering in the Fedorova-Pana massif.

(in Russian, стр.4, fig. 3, tables. 0, ref 7, MS Word 95, MS Word 95 3200 Kb)