stripes
This intrusion comprises two fragments: the Upper massif and the Middle massif, both of which lie in limestones and terrigenous sediments of Carboniferous age. The Upper massif is a circular structure of 16 km2 the outer part of which consists of tourmaline-bearing granosyenites and peralkaline granites and the central part of quartz-aegirine syenites. Granite and syenite pegmatites are broadly developed. The Middle massif is an oval body of 9.5 km2 from the periphery to the centre of which a narrow zone of normal granite grades into peralkaline syenite, amongst which aegirine granite (sviatonossite) occurs. The centre of the massif consists of small bodies of garnet-nepheline syenite. The intrusion is crossed by lamprophyre dykes and pegmatites containing such rare minerals as sogdianite, tienshanite, searlesite, neptunite and hyalotekite (Grew et al., 1994), for some of which this is the type locality.
DUSMATOV, V.D. 1970. Mineralogy of the Dara-Pioz massif (Tadzikistan). In Questions of the geology of Tadzhikistan, 131-6. Geological Institute of Tadzhikistan, Dushanbe.
*GREW, E.S., YATES, M.G., BELAKOVSKIY, D.I., ROUSE, R.C., SU, S-C. and MARQUEZ, N. 1994. Hyalotekite from reedmergnerite-bearing peralkaline pegmatite, Dara-i-Pioz, Tajikistan and from Mn skarn, Langban, Varmland, Sweden: a new look at an old mineral. Mineralogical Magazine, 58: 285-97.