Kharly

The Kharly complex is a stock-like intrusion of 9.2 km2. It cuts Proterozoic marbles and in the north is terminated by a large fault. In the southern part a primary zonal structure is preserved. The following zones, going from the country rock dolomitic marbles towards the central nepheline syenites, have been distinguished: (a) An outer contact zone, 0.5-2.5 m thick, of recrystallized marble with apatite, nepheline, pyroxene and injections of ijolite and foyaite. (b) A central contact zone, varying from 15-110 m to 400-550 m wide, of fine- and medium-grained ijolites with numerous xenoliths of altered country rock limestones. Commonly the xenoliths are present as banded, stratified bodies which range in size from 0.8x1.5 to 40x175 m. (c) The inner contact zone is from several meters to 60 m wide; it is composed of juvites. There is a sharp boundary between the juvites and the ijolites of the outer contact zone, but there is a gradational boundary between the juvites and nepheline syenites of the central part of the massif. At the contact with juvites the ijolites are recrystallized and porphyritic and poikiloblasts of Na-orthoclase appear while pyroxene is replaced by ferro-hornblende and garnet develops. (d) The central part of the Kharly zoned ring structure consists of trachytic aegirine-hedenbergite foyaites. They comprise 50-70% microcline, 20-30% aegirine-augite, 20-30% nepheline and albite, calcite, hastingsite, biotite, titanite and accessories including zircon, ilmenite and magnetite. A series of veins consists of nepheline-feldspar pegmatites with apatite, calcite and lepidomelane; calcite veins contain clinopyroxene, mica, apatite and titanomagnetite and look like carbonatite. Calcite from ijolites, foyaite pegmatite and carbonatite-like veins gave Ù18Oo/oo SMOW from 15.4 to 17.2 and Ù13Co/oo PDB from -2.8 to +1.5, apparently indicating a mixed source. Dykes of aegirine-diopside syenite are also present.