NOBLE-METAL MINERALIZATION OF THE VÄLIMÄKI MASSIF, NORTHERN PRILADOZHJE, KARELIA

Abstract

The 1.89 Ga Välimäki massif is located in the northern Lake Ladoga area (Priladozhje). It is differentiated from wehrlites and pyroxenites to highly alkaline gabbro and diorites. Ilmenite-titanomagnetite ores confined to the pyroxenite portion of the massif form several bodies worked out as early as the 19th – early 20th century. High-grade titanomagnetite ores typically contain high concentrations of TiO2 (2.4–6.4 %), V2O5 (0.54–0.8 %) and MnO (0.16–0.3 %). Titanomagnetite with ilmenite disintegration lamellae contains 0.6–1 % V; Mn concentration in ilmenite is 1–1.87 % in the ores and up to 4.65– 6 % in disseminated mineralization in gabbro-diorites. Ores with disseminated-veinlet Cu-S-mineralization were found to contain noble metals such as Au, Pt and Pd (total concentration 0.3–1 g/t). Sulphides are represented by chalcopyrite and pyrite; sphalerite (Fe 6–9 %), pyrrhotite, argentopentlandite, galena, Se-galena, molybdenite, cobaltite and Ag-Bi-Te phases (hessite, stutzite, tellurobismuthite and tetradymite) are common. Minerals Pd and Pt – michenerite, froodite, merenskyite, Rh-sperrylite, and electrum, were revealed in the Välimäki massif for the first time.

Keywords

• массив вялимяки
• ильменит-титаномагнетитовые руды
• aupd-pt-cu-s-минерализация
• карелия