Akhbasai

This occurrence is situated on the southern slope of the Zeravshansky mountain ridge and takes the form of a stratified body extending in a northeasterly direction for 7 km but having a width of only 500-600 m. The rocks of the intrusion comprise two phases, the first of which consists of syenites and quartz syenites that form a strip in the marginal contact zone. They have been altered under chlorite facies conditions and albitized. The second phase, which is predominant, is represented by foyaites and phonolites. Fine-grained foyaites are not widely developed and generally form xenolith-like bodies. In the central part of the massif the foyaites have a pegmatitic grain size while pegmatite veins from several centimetres to 1-2 meters across are also broadly developed. Dyke rocks including tinguaite and liebenerite and nepheline microsyenite, occur within the limits of the intrusion. Subvolcanic bodies of liebenerite phonolite are also present.