Verkhne-Burul’Zaiskii

This intrusion extends over some 2.7 x 7 km and includes primary liebenerite syenites, which cover about 70% of the area, biotite-muscovite, cancrinite and nepheline syenites, juvites, urtites, ijolites and melteigites. The massif mostly intrudes Upper Proterozoic limestones and Cambrian sandstones and quartzites, and probably Lower Palaeozoic to Upper Proterozoic gabbroids and granites are also involved. The rocks of the urtite-melteigite series comprise nepheline, aegirine-augite, and a small amount of amphibole (hastingsite, arfvedsonite, riebeckite), garnet, titanite, calcite, biotite, apatite, magnetite and secondary minerals including cancrinite and zeolites. Unaltered nepheline syenites are preserved in small areas and composed of alkali feldspar (45-50%, nepheline (3-40%), aegirine-augite (6-15%), hastingsite and alkali amphiboles (0-20%), biotite (0-15%); calcite, garnet, titanite, magnetite, apatite and secondary cancrinite and zeolite are also present. Chemical compositions will be found in Sharackshinov (1984a) and Andre’E va and Troneva (1986).