Scientific publications

Three tectonically isolated prospects of Severny locality - Western, Central and Eastern - are distinguished in the northern Shalozero block. They differ in the structure of the sections of the Layered series and the Lateral marginal zone. In the Layered series sections in the northern Shalozero block pigeonitic gabbronorites typically occur in the pyroxenite zone, sometimes making up 30-50% of its volume; some horizons and the upper subzone of the gabbronorite zone wedge out along the strike and dip; and taxitictextured rocks are distributed irregularly in the gabbroids. Two major strata-bound levels of noble-metal, low sulphidetype mineralization, such as zone B and horizon A, are distinguished in the column of the Layered series. Zone B, varying in thickness from 13 to 54 m, is restricted to the lower part of the pigeonitic gabbronorite unit and to the top of the gabbronorite zone. Maximum platinoid concentrations (up to 1.3 g/t) were estimated in the sulphide-enriched horizons of taxitic and mesocratic gabbronorites. The mineral forms of platinum metals and native gold were determined for the first time in the pigeonitic gabbronorite zone. PGM horizon A is located in mesomelanocratic gabbronorites in the middle part of the pyroxenite zone unit, beneath the sulphide horizon. Its maximum thickness of 15 m was estimated in the intrusion scarp, in the gently dipping rock unit. Platinoid distribution in the horizon is irregular, varying from 0.12 to 1.07 g/t. The mineral forms of BM, represented by telluro-bismuthides and Pd and Pt arsenides, were determined.