Dzhilisu

Located in the nucleus of a syncline of psammites and granites, the Dzhilisu intrusion is composed principally of biotite- and aegirine-augite-nepheline syenites with gradational contacts. In the upper part close to the roof are heterogeneously grained syenites with dykes of nepheline and alkaline syenite aplite. Further into the intrusion there are evenly grained nepheline syenites and pegmatite bodies. In the upper parts of the intrusion particularly, there has been extensive albitization that involved the syenites and marginal schists.