Thanks to the author of the
article below and to László Horváth for his help.
The „plateau covered with onions“ - that´s what Dara-i-Pioz means, is a very remote area located in the southern Tienshan Mountains close to the Pamirs in Tadzhikistan. Dara-i-Pioz is the name of a river, a plateau, a glacier and a pass. The area was first explored as late as in the 1920s-1930s and is still under study.
The Dara-i-Pioz massif (sooner: massifs - the Upper and the Middle massif) mainly consists of paleozoic alkaline granitoides, which penetrate metamorphic silurian schists. A main feature of the granitoides is their high content of boron. The most common accessory mineral is schorl, to a lesser degree axinite. The granitoides are crossed by albite-aegirine-microcline metasomatites veins of up to 100 m,. In these metasomatites there are extensive series of different, though mostly alkaline, pegmatite veins of several cm to several m. Quartz-microcline-aegirine pegmatites are most common. There are, however, some blocks of miaskitic nephelin-aegirine-feldspar pegmatites, which seem to stem from alkaline intrusion that did not reach the surface. The different rocks and minerals are to be found in blocks on and around the glacier.
The mineralogical research started in the 1960s (Dusmatov and Alchasov). Geologically and mineralogically there are similarities to Kola, Ilimaussaq and Mt.St.Hilaire. Minerals containing boron are typical for this locality. Inclusions of e.g. eudialyte and aegirine in quartz are characteristic. The mineralisation can be divided into three types:
A:granitoides: subalkaline granodiorites with albite and microcline rich in bor
B:coarse grained metasomatites
1a: quartz-microcline-pegmatites with astrophyllite, embedded in granite and up to several cm thick
1b: pegmatites with coarse schorl and quartz, several dm thick
2a: aegirine-microcline-quartz pegmatites in
granitoides with steacyite, up to several m thick
2b: aegirine-quartz-microcline pegmatites in granites with hejtmanite and zektzerite, up to several m thick
2c: quartz-aegirine-microcline pegmatites in granites close to metasomatites with neptunite and zektzerite, up to several m thick
2d: quartz-aegirine-microcline pegmatites in granites with miserite - the most interesting ones
3a: quartz cores, probably from broken 2d-pegmatites
3b: feldspar pegmatites blocks
3c: blocks of microcline and coarse grained reedmergnerite
As no surprise with the complicated geology the mineral list is quite long.
Mineral list (bold=type locality)
Hyalotekite (probably a new h.-related mineral)
Neptunite (and/or Manganneptunite)
Steaceyite (doubtful, allegedly always turkesanite)
Turkestanite (co-type loc.)
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Belakowski,D.I.: Die seltenen Mineralien von Dara-i-Pioz im Hochgebirge Tadshikistans, LAPIS, 16(1991), 12, pp.42-48
Kogarko,L.N., V.A.Kononova, M.P.Orlova, A.R.Woolley: Alkaline Rocks and Carbonatites of the World. Part 2: Former USSR. Chapman and Hall, London, 1995.
Reguir,EP et al.: The mineralogy of a unique baratovite- and miserite-bearing quartz albite aegirine rock from the Dara-i-Pioz complex, northern Takikistan. CANADIAN MINERALOGIST, 37(1999), 1369-1384