Ingurskii

This 140 km2 massif, like Sherbakhtinskii (No. 33), cuts early Proetrozoic metamorphic rocks and Palaeozoic granites and is partly covered by Neogene basalts. The intrusion is characterized by the concentric disposition of the rock units: biotite granite in the centre and peralkaline granites around the margin. The peralkaline granites occupy about 100 km2 and veins and dykes are abundant and include peralkaline granite pegmatites, granite porphyries and syenite porphyries. The peralkaline granites are coarse-grained, sometimes porphyritic and composed of alkali feldspar, quartz, aegirine and riebeckite.