stripes
The Anmandykanskii pluton occupies an area of about 310 km2 and cuts Precambrian metamorphic rocks. The complex has a concentric zonal structure with quartz syenites in the central part while around the periphery are quartz-bearing syenite, syenite, peralkaline syenite and nepheline syenite. The nepheline syenites form sheet-like bodies with thicknesses up to 30 m. The peripheral rocks have layered structures. Thus, in the western part of the margin of the pluton, in a zone 2.5 km wide, there are up to 22 units formed of nepheline and alkaline syenites and microcline rocks. The nepheline syenites are medium- and coarse-grained porphyritic rocks composed of microcline-perthite (45-70%), nepheline or sericite pseudomorphs after nepheline (30-45%), biotite and aegirine (5-10%); there is also some albite, cancrinite, melanite and accessory minerals including titanite, apatite, zircon and Ti-Fe oxide minerals.
FADEYEV, A.P. and SHPETNY, A.P. 1978. The peculiarities of geological structure and history of formation of the Anmandykanskii alkaline pluton. Materials on the geology and mineral resources of the North-East of the USSR. 24: 53-60. Magadan.
ZALISHCHAK, N.L. 1978. Alkali magmatic rocks. In Geology of the Pacific Mobile Belt and the Pacific Ocean. 2: 66-82. Nedra, Leningrad.
