Institute of Geology of Karelian Research Centre of RAS (Petrozavodsk, Russia):

Ivashchenko V. I., Leading Researcher, Candidate of Geological and Mineralogical Sciences, e-mail: ivashche@krc.karelia.ru

Golubev A. I., Head of Laboratory, Candidate of Geological and Mineralogical Sciences

About 200 gold ore localities (5 small deposits) are now known in Karelia. They are divided into several genetic types: orogenic mesothermal, mesothermal, porphyric (intrusion-related), volcanogenic massive sulphides (VMS); epithermal (+metamorphism); iron oxide copper gold (IOCG) (skarn); and palaeoplacer (conglomerate). They are concentrated dominantly in Neoarchean and Palaeoproterozoic greenstone belts and Svecofennides. An orogenic mesothermal type in shear zones is a leading genetic type of gold mineralization in Karelia and other Precambrian regions. Pedrolampi, Khatunoya and Rybozero are the largest and promising gold localities of this type in Archaean rocks. Maiskoe, Alattu-Päkylä and Janis are the largest localities in Proterozoic rocks. A gold-porphyry type is represented by Lobash-1 deposit and several large ore occurrences (Jalonvaara, Päävaara, etc.). Gold occurrences of other genetic types in Karelia are scarce. They are small and not promising. Over 90% of gold reserves are concentrated in Proterozoic structures in Finland and Sweden. By analogy with these countries, the economic gold of Proterozoic age in Karelian region is more likely to occur in Raahe-Ladoga, Onega-Lapland and Vetreny Poyas structures.

Based on original data and systematic generalization and analysis of the literature on platinum group materials` (PGM) mineralization in Karelia, there are described its major ore-formation types, such as:

- low-sulphide platinum-palladium type;

- a Pt-Pd titanomagnetite type with gold and vanadium in gabbro-dolerites (Pudozhgora type);

- a polygene Cu-U-Mo-V platinum-palladium type with gold (Padma type). Its gold is situated in albite-carbonate metasomatic rocks from the carbonaceous-shale units of folding-faulting zones.

New data on Au, Pt and Pd concentrations in the Koikarsk-Svyatnavoloksk intrusive unit of a trap formation and in the Burakovian layered pluton are presented. The noble-metal potential of a titanomagnetite ore formation in the Onega trough is estimated by approximately 1000 tones. The predicted total platinoid resources of the Karelian region – by approximately 2000 tones - are supported and economic mining potential is shown.

1. Ivashchenko V. I., Golubev A. I. Zoloto i platina Karelii: formatsionno-geneticheskie tipy orudeneniya i perspektivy (Gold and platinum of Karelia: formational and genetic types of mineralization and prospects). Petrozavodsk : Karelian Scientific Center of Russian Academy of Sciences, 2011, 369 p.

2. Mineralno-syrevaya baza Respubliki Kareliya. Kniga 1 (Mineral and raw material base of the Republic of Karelia. Book 1). Under the general editorship of B. P. Mikhailov and V. N. Aminov. Petrozavodsk : Kareliya, 2005, 278 p.

3. Korovkin V. A., Turyleva L. V., Rudenko D. G. et al. Nedra Severo-Zapada Rossiyskoy Federatsii (A subsurface of the North-West of Russian Federation). Saint Petersburg, 2003, 520 p.