Kulpskii

The Kulpskii intrusion is located in the core of an anticline of Silurian and Carboniferous limestones, schists and phyllites. The intrusion is formed of three phases, namely nepheline syenites, syenites and quartz syenites, and tourmaline-bearing granites. The rocks of the first two phases contain numerous xenoliths of schist. The nepheline syenites occur in the northwestern and northeastern parts of the intrusion, as well as in east-west-trending zones in the central and southern parts of the massif. They are mostly biotite-bearing varieties with less abundant amphibole and amphibole-pyroxene types; there are also sodalite- and canrinite-bearing varieties. The syenites and quartz syenites form an elongate body in the central part of the intrusion within which pyroxene-, biotite- and tourmaline-bearing variants have been distinguished. Fine-grained, leucocratic granites with patches of tourmaline form dykes in the central and eastern parts of the intrusion. Many minerals, including albite, sodalite, cancrinite, tourmaline and quartz, are considered to be the result of secondary processes.